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SCHEME OF WORK
1 Revision / Modes of Nutrition
i. Autotrophic nutrition
a. Chemosynthetic Nutrition
b. Photosynthetic Nutrition
ii. Heterotrophic Nutrition
a. Holozoic
b. Parasitic
c. Symbiotic
d. Saprophytic
e. Carnivorous Plants

2 Relevance of Biology to Agriculture
a. Classification of Plants
i. Botanical Classification
b. Effects of agricultural activities on ecological systems
i.Bush clearing /burning
ii.Tillage
iii.Fertilizer/herbicide application and their effect
iv.Effects of different types of farming on ecosystems

3 A. Pests of Agricultural importance
i. Definition of pests
ii. Effects of pests
iii. Control of pests
B. Disease of agricultural importance
i. Definition of disease
ii. Types of diseases ( viral, bacteria, fungal etc)
iii. Effects of diseases on crop plants
iv.
v. Types of pests Control and prevention of diseases

4 Food Production and Storage
i. Ways of improving crop yield
ii. Causes of food wastage
iii. Methods and principles of food preservation and storage
iv. Population growth and food supply
v. Reproduction and population growth

5 Human Reproduction
Menstruation and Ovulation
i. Ovulation period
ii. Fertility period
iii. Difficulties in predicting ovulation
iv. Menstrual Hygiene

6 i. Male sexual maturation
ii. conception
iii. Signs of pregnancy
iv. Normal pregnancy
v. Types of child delivery

7 BASIC ECOLOGICAL CONCEPTS
Ecosystems: Components and Sizes
i.Ecological concepts (Environment, Biosphere, Habitat, etc)
Components of an eco system (Abiotic, Aquatic, Terestrial, etc)

8 BIOMES
i.Local biomes ion Nigeria (Tropical rainforest, Southern, Guinea savanna, Mangrove, etc)
ii. Major biomes of the world (Temperate rain forest, Tundra, desert, Alpine, etc)

9 POPULATION
I.Population studies methods
a. Population size
b. dominance
c. density
ii. Factors that affect population (food, death, birth, migration etc)
iii.Simple measurement of ecological factors and instrument used.

10 FUNCTIONING ECOSYSTEM
a. Autotrophic and Heterotrophs
b. Trophic levels (Food chains and food web)
c. Energy flow
d. Energy transformation in nature

i. Energy loss in the eco system
ii. Laws of thermodynamics
iii. Nutrient Cycling
iv. Decomposition in nature

11 - 12 Revision


NEW
WEEK TOPIC

THEME: THE ORGANISM AT WORK

1. Revision of work done in first term
2. Nutrition in Animals :(a) Food substances (i)Types of food substances (ii) Balanced diet (b)Heterotrophic Nutrition (i) Types of heterotrophic Nutrition.
(c)Feeding Mechanisms in Holozoic Organisms (d) Mammalian teeth (c) Enzymes.
THEME: THE ORGANISM AND ITS ENVIRONMENT
3. Basic Ecological concepts :(a) Ecological concepts (b)Components of an ecosystem (c)Local biotic communities or biomes.
4. Basic Ecological concepts : (d)Major biomes of the World(e)Population studies by sampling method (f)Ecological factor (g)Relationship between soil types and water holding effect of soil on vegetation(h) simple measurement of ecological factors.
5. Functioning Ecosystem:(a)Autotrophy and heterotrophy (i) Producers (ii)Consumers (iii)Aquatic and terrestrial
6. Food webs and Tropic level :(a)Tropic levels (i)Food chain (ii) Food web (iii)Non cycle nature of chemical energy transfer (iv)Nutrient movement (b) Energy Flow (i) Food energy relationship in aquatic and terrestrial environments (ii)Pyramid of energy/numbers (iii)Nature of energy flow.
7. Energy Transformation in Nature :(a)Energy Loss in the ecosystem (i)Solar radiation (ii)Energy Loss in the biosphere (iii)Measures of primary production e.g the amount and rate of energy fixation (b)Laws of thermodynamics.
8. Relevance of Biology to Agriculture :(a) Classification of Plants (i) Botanical Classification (ii)Agricultural Classification (iii) Classification based on life cycles (b)Effects of agricultural activities on ecological systems(c)Pests and diseases of agricultural importance.
9. Relevance of Biology to Agriculture: (d) Food production and storage(i)Ways of improving crop yield(ii)Causes of wastages (iii)Methods of preserving and storing food (e)Population growth and food supply(f)Relationship between availability of food and human population-effect of shortage(g)Government efforts to increase food production e.g agriculture revolution.
10. Micro Organisms Around Us:(a) Micro organisms in air and water (i) Group of micro- organism :bacteria, viruses ,some algae, protozoa and fungi (ii)Concept of culturing (b)Identification of micro- organisms in (i)air (ii)pond water (iii)river (iv)stream
(c)Micro-organisms in our bodies and food (d) Carriers of micro organisms –examples, location of microorganism in carriers and types of micro organisms.
11. Revision.

TOPIC: ANIMAL NUTRITION
CONTENT: 1. Food substances (i) Types of food substances (ii) Balanced diet
2. Heterotrophic nutrition (i) Types of heterotrophic nutrition
3. Feeding mechanism in holozoic organisms
4. Mammalian teeth
5. Enzymes

Sub- Topic 1: Animal Nutrition
All living things feed in order to obtain energy for their daily activities and also to carry out their metabolic processes. Plants can manufacture their own food (i.e. make complex chemical compounds) from simple raw materials (CO2 and H2O) through the process of photosynthesis. Plants need minerals to make some of the complex compounds and these are obtained from the soil as mineral ions. Animals however cannot manufacture their own food, they depend directly or indirectly on plants. Nutrients that animals require are present in their diet.


Hamburger and Fries
One of the meals most associated with the United States is a hamburger and french fries. This burger and fries, a daily special, is accompanied by baked beans and coleslaw.








Food Substances
All food taken in by animals can be divided into six groups of food nutrients namely Carbohydrates, Protein, Fats, Vitamins, Minerals, and Water. Fibre/roughage is also an important component of a diet but it is not a nutrient. All these are needed for a balanced diet, for humans.
Carbohydrates, Protein, Fat & oil, and Water are primary food substances and are necessary for the maintenance of life. Minerals salts and Vitamins are welfare food substances and are essential for the well being of an individual.

Types of Food Substances

A. CARBOHYDRATES
These contain the elements carbon (C), hydrogen (H) and Oxygen (O). The ratio of hydrogen to oxygen is 2:1. Carbohydrates are represented by the formula Cx (H2O)y. The major sources of carbohydrate are Sugar (e.g. glucose, maltose) and starches (e.g. yam, maize, rice).

Types of Carbohydrates
1) Monosaccharides / Simple sugars: These are made up of only one unit of simple sugar e.g.
(a) Hexose sugars: These consist of six carbon atoms arranged into a ring e.g. glucose, fructose and galactose. They make up the most important energy storage molecules in an organism. Their chemical formula is C6H12O6
(b) Pentose sugars: These consist of five carbon atoms e.g. ribose and de-oxyribose. They are used in the formation of nucleic acids.

2) Disaccharides / Complex sugars: These are formed by the condensation (i.e. chemical bonding of two molecules) of two simple sugar molecules. They are represented by the formula C12H22O11 .
Examples are:
(a) Maltose (glucose + glucose – H2O) found in malted cereals and spouting grains.
(b) Lactose (glucose + galactose – H2O) found in milk.
(c) Sucrose (glucose + fructose – H2O) found in sugar cane stems, ripe sweet fruits, sugar – beet and carrot.
NB All sugars are sweet and soluble and provide energy in a ready-to-use form.

3) Polysaccharides: These are formed by the condensation of hundreds of simple sugar molecules. They are represented by the general formula
(C6 H10O5) n where n represents a large number. Examples include starch, cellulose, glycogen (animal starch). Starch and glycogen are insoluble and do not taste sweet.

NB Condensation is a reaction in which two or more molecules join to form a large molecules with the removal of a molecule of water (H2O) or some other simple molecule.

Improtance of Carbohydrates
(i) They provide us with energy.
(ii) It provides heat during its oxidation which is used in maintaining body temperature.
(iii) It is used in building the exoskeleton of arthropods.

B. PROTEIN
Proteins are complex molecules made up of carbon, hydrogen, oxygen and nitrogen (N) many also have sulfur (S). They are long – chain molecules made up of smaller molecules called amino–acid. There are 25 types of amino acids and these occur in different numbers and order in different types of protein. Thus one protein is different from the other. Each individual amino acid joins the chain by means of a peptide bond.
During digestion the breakdown of protein occur in the following sequence;
Protein → Proteoses → Peptones → Polypeptides → Amino Acids.
Examples of Proteins include:
(a) Soluble proteins e.g. haemoglobin (in blood), enzymes (in water/cytoplasm), antibodies, and some hormones (e.g. insulin).
(b) Insoluble proteins e.g. keratin (a fibrous protein found in skin and hair), collagen (found in bones and cartilage), myosin and actin (found in muscle cell). Sources of protein include (a) animal sources such as fish, meat, milk, egg and cheese. (b) Plant sources such as beans, groundnut and soya beans etc.


Cooking Meat
Chefs prepare meat for cooking in a restaurant kitchen in Buenos Aires, Argentina. Cooking methods depend on the cut of meat: Tender meat may be easily roasted or grilled, while tougher cuts may require stewing or boiling.

(i) Protein is used for making body building substances which are necessary for building new cells and replacing old ones.
(ii) Essential for the repair of cells and worn- out tissues.
(iii) Essential for formation of enzymes
(iv) Essential for formation of hormones
(v) Essential for formation of antibodies
(vi) Essential for formation of heamoglobin etc.
(vii) Essential components of cell membranes
(viii) It may be required to provide energy.

C. FATS AND OILS
These are also called lipids and are composed of carbon, hydrogen and oxygen. Each fat molecule is made up of one molecule of glycerol attached to 3 fatty acids. There are different types of fatty acids and these form different fats with different properties. At room temperature fats are solid while oils are liquid. Lipids are macromolecules and have to be broken down into fatty acids and glycerol before they can be absorbed into the body. Sources of fats include margarine, butter, cheese, fatty meat, melon, groundnuts, palm fruits, castor oil seeds, lard etc.

IMPORTANCE
(i) Fats and oil are used for energy storage in the body. They provide more energy to the body than carbohydrate when metabolized.
(ii) They are solvents for fat soluble vitamins and also for hormones.
(iii) They are important components of cell membranes.
(iv) They help in maintaining the body temperature / for thermal insulation in the body. In cold countries, the fat layers under the skins of mammals act as insulators and prevent loss of heat from their bodies.
(v) Fats give buoyancy to marine animals e.g. whales have a thick layer of blubber.

D. MINERAL SALT
These regulate the metabolic activities within the body. They are also important components of enzymes, pigments and structural parts.
The major source of mineral salts is the diet. Examples of minerals include sodium, potassium, calcium, chlorine, phosphorus, magnesium, iron, copper, cobalt, fluorine and manganese.
Sodium calcium and phosphorus are needed in large quantities in the body while some others like iron and iodine are only needed in small quantities.
A lack of minerals in the diet results to ill health and development of symptoms of deficiency diseases.

SOURCES, FUNCTIONS AND DEFICIENCY SYMTOMS OF SOME MINERALS
Mineral Function Deficiency symptom Sources / Daily need
Iron Formation of haemoglobin in red blood cells; myoglobin in muscle cells and enzymes involved in cell respiration. Tiredness, lack of energy (Anaemia) Liver, meat, cocoa, eggs, green vegetables (10mg)
Calcium Strengthens bones and teeth; needed for blood clotting, proper functioning of heart and nervous system, and normal contraction of muscles. Weak, brittle bones and teeth (Rickets)
Muscle weakness and cramps. Milk, fish, green vegetables (1g)
Sodium Important component of blood plasma; maintains correct osmotic pressure of body fluids; needed in transmission of impulses in nerves, sensory cells and muscles and for normal cell membrane permeability. Dehydration muscle cramps, kidney failure. Salt, natural foods especially meat, milk and eggs
(5-8g)
Phosphorus Involved in transfer of energy, required for most chemical reactions in the body ; essential component of DNA and RNA; major component of bones & teeth. Rickets Fish, shell-fish,eggs,milk and cheese.(1.5g)

E. VITAMINS
These are organic compounds required by man and other animals in only small quantities for normal growth and healthy development. They are biocatalysts (they promote chemical reactions in the body).
Examples include vitamins A, D, E and K which are water soluble. The main sources are fruits, eggs, milk, palm oil, vegetables and animal organs. Inadequacy or lack of these vitamins leads to nutritional deficiency diseases and ill health.

SOURCES, FUNCTIONS AND DEFICIENCY SYMTOMS OF SOME VITAMINS
Vitamin Function Deficiency Symptom Sources
(1) Vitamin A
(Retinol) (i) For normal growth of body cells and skin
(ii) For proper vision of the eye in dim light. (i) Skin becomes flaky.
(ii) Night blindness
(iii) Xerophthalmia Fish – liver, oil, egg yolk, green and yellow vegetables, fruits.
(2) Vitamin D
(Calciferol)
(i) For strong bone and teeth formation and development.
(ii) It increases the absorption of calcium and phosphorus in the intestine. (i) ricket in children
(ii) Softening of bones in adults (osteomalacia). Fish, milk, egg, liver, butter, synthesized in the skin when exposed to sunlight.
(3) Vitamin E
(tocopherol) (i) Promotion of fertility in animals
(ii) Protects fatty acids and cell membrane from oxidation. (i) Sterility and premature abortion. Leafy green vegetables, seeds, egg, milk, liver.
(4) Vitamin k
(phylloquinone) (i) Aids blood clotting. Slow clotting of blood leading to severe bleeding from cuts
(Haemorrhages). Liver fresh green vegetables, made by intestinal bacteria.
(5) B1
(thiamine) (i) Needed for formation of co-enzymes involved in cellular respiration.
(ii) For normal growth.
(iii) Proper functioning of heart and nervous system. (i) Reduced growth.
(ii) Beriberi (a disease of the nervous system). Yeast, rice bran, beans, groundnut, liver.




(6) B2
(Riboflavin)
(i) For formation of co-enzymes involved in cellular respiration
(ii) For growth, healthy skin and proper functioning of the eye. (i) Slow growth.
(ii) Sores in skin (dermatitis) and around the mouth. Eggs, liver, kidney, yeast, leafy vegetables.
(8) B5
(pantothenic acid or Folic acid) (i) For formation of co-enzymes in cellular respiration.
(ii) For formation of red blood cells. Disorder of nervous system and gut.
Anaemia Yeast, eggs, rice bran.

Leafy vegetables, liver.
(9) Vitamin C
(Ascorbic acid) (i) For maintenance of connective tissues, bones and dentine
(ii) Helps to resist inflection (i) Scurvy
(ii) Wounds heal slowly. Fresh citrus fruits, pawpaw, guava, green vegetables.


Apples
The apple tree is widely cultivated throughout temperate regions of the world for its juicy, edible fruit. The many varieties of apples have been popular for centuries and growers have selectively bred certain superior wild varieties for domestication and mass production.

F. WATER
This is composed of hydrogen and oxygen and makes up two-thirds (70%) of the body mass of a human being.
Water is taken in when we eat or drink. Sources include metabolic water from food, water from rivers, rain, ponds, springs, etc.

IMPORTANCE
(i) It is required for metabolic activities in the body. It makes up a large part of the protoplasm, thus it is the medium in which chemicals reaction take place in the body.
(ii) It transfers digested food substances, excretory products (urine & sweat) and hormones.
(iii) It plays an important role in the regulation of body temperature (sweat cools us down)
(iv) It helps to maintain the osmotic content of the body tissues.
(v) It is an important solvent for food substances during digestion.
(vi) It constitutes a greater part of the blood.
(vii) It is the main component of plants and animals.
Daily intake of water must equal the loss in urine, faeces, sweat and breath to keep healthy.

G. ROUGHAGES / FIBRE
This is indigestible fibrous materials derived mainly from vegetables, fruits and seed coats (of carbohydrates and proteinous seed).
Fibre adds bulk to food thus stimulating the movement of the bowel. It passes down the entire gut from mouth to anus and does not provide any energy.
Sources include bran cereals, cabbage, sweet corn, celery, etc.


Papaya Fruit
A view of the interior of the papaya fruit shows the pulp and seeds. This edible fruit, capable of growing as large as 9 kg (20 lb), is widely cultivated in the tropics. The latex of the fruit contains a substance called papain, which can be extracted and used to tenderize meat.


IMPORTANCE
(1) Fibre helps the movement of food in the alimentary canal by peristalsis so preventing constipation.
(2) Fibre absorbs poisonous waste from bacteria in the gut.
(3) Many doctors believe a high fibre diet lowers the concentration of cholesterol in the blood.
(4) Fibre reduces the risk of heart diseases and bowel cancer.


BALANCED DIET
The intake of a variety of food in the right quantity and proportion that provides the body with all the nutrients and energy needed to sustain the body and ensure good health and growth is referred to as a balanced diet.
A balanced diet must contain the seven food substances i.e Carbohydrates (60%), Proteins (15%), Fats (15%), Vitamins (10%), Minerals,Water and Fibre.


ENERGY REQUIREMENTS
Even at rest energy is required for basic functions such as heart beats, working of the lungs and keeping body temperature constant. Also chemical reactions in the body such as those involved in growth & repair are occurring and these need energy. The energy required for these body functions is called the basal metallic rate.
USDA Food Pyramid
The United States Department of Agriculture Food Pyramid provides a practical visual guide to healthful eating, indicating the recommended daily portions of the basic food groups.

(BMR). BMR varies from person to person; an adult needs 7000kg per day, even at rest this energy is still required.

THE IMPORTANCE OF A BALANCED DIET
(1) It is required for normal healthy living.
(2) It gives us resistance to diseases.
(3) It provides energy required for normal activities.
(4) It prevents malnutrition / deficiency diseases e.g. a lack of protein in the diet can cause kwashiorkor and marasmus in children.

EVALUATION
1. Name the constituent element, four food sources and three functions of each of the following (i) Carbohydrates (ii) Protein (iii) Lipid
2. List the sources and functions of four vitamins and minerals.
3. State one deficiency disease/condition associated with each type of nutrient mentioned in 1 and 2 above
4. Define the terms: (a) balanced diet (b) BMR
5. Mention three importance of taking a balanced diet

SUGGESTED PRACTICALS
FOOD TESTS
The materials / nutrients present in food can be identified using various types of tests. These are:
(1) Test for carbohydrates
(a) To test for simple sugar e.g. glucose and fructose.
Put a small quantity of glucose solution in a test tube.
Add an equal amount of benedict solution.
Boil the mixture for 4 - 6 minutes. A bricks-red or orange precipitate indicates the presence glucose.
(b) To test for complex sugar e.g. sucrose, maltose or lactose
Put a small quantity of the sucrose solution in a test-tube
Add a few drops of dilute hydrochloric acid to the solution, (This hydrolyses the complex sugar to simple sugar)
Place the test-tube in a boiling water bath for a few minutes.
Add a few drops of dilute caustic soda (to neutralize the excess acid).
Add an equal amount of feeling’s solution and place the test-tube in a boiling bath. An orange-red precipitate / yellow precipitate indicate the presence of sucrose.
( c) To test for starch
-Boil a sample of the starch material (e.g. yam / rice)
-Add a few drops of dilute iodine solution to it. A blue-black colouration indicates
the presence of starch.

(2) To test for proteins
(a) Biuret test
-Take a small quantity of fresh milk, egg white solution or malt extract in a test-tube.
-Add a few drops of water and 1cm³ of dilute sodium hydroxide.
-Carefully add 1% of copper II sulphate solution in drops. Shake the mixture thoroughly after each drop.
-A violet, purple, violet colour indicates the presence of protein
-A pink colour indicates the presence of peptones.
(b) Millon’s test
-Put 3cm³ of egg white / colloidal solution of a protein into a test-tube
-Add 3cm³ of millon’s reagent and warm the mixture in a water bath for a few minutes.
-A deep red colour or precipitate shows the presence of protein.
(c) Xanthoproteic test
-Put 2cm³ of egg white or milk solution in a test-tube.
-Carefully add about 1cm³ concentrated trioxonitrate (v) acids. A white precipitate forms which turns yellow on heating.
-Cool the contents and add about 3cm³ of ammonium hydroxide solution. Heat the solution and allow it to cool. The colour of the precipitate deepens to orange indicating the presence of protein.
(3) To test for fats and oils
(a) Translucent mark test
Drop oil on a spot, on a piece of paper or rub the surface of a fatty food against the surface of a piece of white paper. A translucent mark shows the presence of fat.
(b) Sudan III test
-Add a few drops of sudan (iii) solution to some oil in a test-tube. A red colouration is obtained
-Boil the solution. A black precipitate is formed.

EVALUATION
Briefly describe one method of identifying the presence of the following in food substances (a) Glucose (b) Sucrose (c) Starch (d) Protein (e) Fats and oil

WEEKEND ASSIGNMENT
OBJECTIVE TEST
1.During which of the following processes is food for animals produced? (a) Digestion (b) Photosynthesis (c) Respiration (d) Transpiration
2. Which of the following is the odd one out? (a) Calcium (b) Calciferol (c) Iron (d) Manganese
3. The deficiency of vitamin D leads to (a) pellagra (b) polio (c) rickets (d) scurvy
4. Which of the following food substances turns bright red when warmed with Sudan III solution? (a) Fat (b) Protein (c) Reducing sugar (d) Starch
5. The arrangements below are steps in protein digestion. Which is the correct sequence?
I. Amino acid II. Peptone III. Polypeptide IV. Protein
(a) I→ II→ III→ IV (b) II→ III→ I → IV
(c) II→ IV → I→ III (d) IV → III→ II→ I


Pre Reading Assignment
Read up Heterotrophic nutrition


Sub- Topic 2: HETEROTROPHIC NUTRITION
This is the type of nutrition in which the organism feeds on complex organic molecules. There are different forms of heterotrophic nutrition.

Types of Heterotrophic Nutrition
1. Holozoic Nutrition: In this type of nutrition an organism feeds on complex organic materials, usually in solid form. These materials require ingestion, digestion and absorption before assimilation into the body.
Animals that practice holozoic nutrition include herbivores, carnivores and omnivores.
2. Parasitic Nutrition: In this form of nutrition, one organism (the parasite) lives in or on another organism (the host) causing harm/death to the host. Parasites may be plants or animals.
Parasitic plants attach themselves to the host by means of suckers and send special absorbing organs called haustoria into the tissues of the host’s stem where they absorb water, mineral salts and food substances. Examples are the dodder plant, cassytha and mistletoe (a partial parasite).



Mistletoe Corn smut
Parasitic animals which live outside the host (ectoparasites) have mouth parts that are modified for piercing or boring into the skin of animals or epidermal layer of plants and suck the body fluid of the host. Examples are ticks, aphids, lice, etc. parasitic animals which live within the host (endoparasites) possess attachment organs such as suckers with which they fasten themselves onto the walls of the host’s gut and suck already digested food. Examples are tapeworm, liverfluke, plasmodium and hookworm.




Tsetse fly; an ectoparasite Chigger; an ectoparasite




Plasmodium; an endoparasie Tapeworm; an endoparasite


3. Saprophytic Nutrition: This is a form of nutrition in which an organism feeds on dead and decaying organic matter. Examples are Rhizopus, mushroom, mucor, toadstool and bacteria. These organisms have rhizoids through which they secrete enzymes into the substrate extracellularly. The digested portion is then absorbed into the body of the saprophyte.

EVALUATION
1. What are heterotrophs?
2. Give and explain two forms of heterotrophic nutrition.

Sub – Topic 3: Feeding Mechanisms In Holozoic Organisms
All animals obtain their food directly from plants or by feeding on other animals. Their nutritional requirements are obtained from ingested food. Various organisms obtain and ingest their food in different ways; this is referred to as their feeding mechanism. The feeding mechanism of an organism depends on the organism’s mode of nutrition and the type of food on which it feeds.
The ingested food is broken down into simple, soluble and diffusible substances through the process of digestion. The digested food is then absorbed into the fluids of the organism and transported to the body cells where it is assimilated (i.e. used). Undigested food is egested from the body.
Feeding mechanism in holozoic organisms include the following;
i. Use of pseudopodia to engulf food e.g. in Amoeba
ii. Beating movement of cilia to move food into the oral groove e.g. Paramecium.
iii. Sweeping movement of flagella to move food into the mouth e.g. in Euglena.
iv. Use of tentacles e.g. Hydra.
v. Filter feeding e.g. Mosquito larvae, whales, oysters, etc.
vi. Fluid feeding e.g. Insects, hummingbirds, etc.
vii. Saprophytic feeding e.g. mushroom, rhizopus, etc.
vii. Parasitic feeding e.g. Dodder plant, Mistletoe, liver fluke, lice, guinea worm,
tapeworm, etc.

EVALUATION
1. Mention to forms of feeding mechanism in holozoic organisms
2. Briefly describe the modification of the mouth parts of a grasshopper to its mode of feeding.
Sub – Topic 4: MAMMALIAN TEETH
The type of teeth possessed by a mammal is related to the type of food it eats. The number, arrangement and conformation of teeth in an organism are referred to as its dentition. When all the teeth are the same shape and size as in fishes, amphibians and reptiles it is called homodont dentition. When they differ in shape as in dogs, man and rabbits it is heterodont dentition.
Mammals usually have four different types of teeth namely the incisors, canines, premolars and molars. Man has two sets of teeth during his lifetime; the milk teeth when young and the permanent teeth when mature. There are 20 milk teeth and 32 permanent teeth.
Types of Teeth
1. Incisors – These are flattened, chisel-like with a sharp edge for cutting and holding onto the food/prey. They are located in the front of the jaw.
2. Canines – These have sharp, pointed tips and are used for tearing flesh. They are next to the incisors.
3. Premolars – These have broad ridged surfaces called cusps. They are used for grinding and chewing food. They are located towards the back of the jaw.
4. Molars – These also have broad, ridged surfaces and are used for chewing and grinding food. They are found at the extreme back of the jaws.



Adult teeth

Dental Formula
This refers to the number, type and arrangement of teeth in one half of each jaw.
Example in;
(i) Man; I 2/2 ; C 1/1 ; PM 2/2 ; M 3/3
(ii) Dog; I 3/3 ; C I/I ; PM 4/4 ; M 2/3
(iii) Rabbit; I 2/1 ; C 0/0 ; PM 3/2 ; M 3/3

Structure of a Tooth
A typical tooth has three parts; the crown, the neck and the root. The crown is the part above the gum. The root is embedded in the jaw and the neck is the part on the same level with the gum, it is the narrow junction between the crown and root.
The incisors and canines have one root each while the premolars and molars have two or three roots each.


In the centre of the tooth is a pulp cavity which contains blood vessels and nerves that make extremely sensitive to heat, cold and pain. The dentine, a hard bone-like material, encloses the pulp. The enamel, a white, hard material covers the dentine, protecting it and the pulp within. At the root region a thin layer of cement covers the dentine. The cement is surrounded by the periodontal membrane, a fibrous tissue that fixes the tooth into the jaw bone.
The tooth is not rigidly fixed but can move slightly while biting and chewing. A hole at the tip of each root allows blood vessels and nerves of the pulp to be connected to those of bones and gums. This ensures a continuous flow of of blood supply to the tooth and keeps the tooth alive. However, the supply of blood is not sufficient for the tooth to grow. This type of teeth is known as closed teeth.

Dental care
Tooth decay caused by bacteria and fermentation of carbohydrates that get stuck in the teeth can be prevented by;
1. Practicing regular oral hygiene
2. Eating balanced diet containing enough vitamin, phosphorus and calcium.
3. Eating hard, fibrous fruits after each meal.
4. Avoiding sweet food, very hot and very cold.
5. Visiting a dentist regularly.
EVALUATION
1. Define the terms (a) dentition (b) dental formula
2. Make a large well labeled drawing of a tooth.
3. State four ways of caring for your teeth

Sub – Topic 5: ENZYMES
An enzyme is an organic catalyst. A catalyst is a substance which brings about or greatly speeds up a chemical reaction and it is not used up or changed during the reaction. Enzymes speed up metabolic reactions in living cells without changing their composition in the
process. Enzymes are protein molecules and are manufactured by an organisms own cells.



Structure and function of an enzyme

TYPES OF ENZYMES
Enzymes are classified based on the nature of chemical changes brought about on a substrate. Example;
(1) Hydrolases: These bring about the decomposition of a substrate by the addition of water molecules to it. This process is called hydrolysis. However, they can also bring about a reverse reaction in which complex substance are synthesized from simple substances by the removal of water (condensation). Most digestive enzymes are hydrolysis enzymes.

E.g. Starch Glucose





(2) Oxido – reductase: These bring about oxidation of a substrate by the addition of oxygen or removal of hydrogen. This reaction is usually accompanied by the reduction of another substance. Most respiratory enzymes such as dehydrogenases, oxidases and catalases belong to this group.
(3) Transferases: These catalyse reversible reactions
(4) Isomerases: These usually change the spatial configuration of a molecule in a living cell. They work on isomers.
(5) Lyases: These catalyse the breaking up of bonds by elimination or addition reactions.
(6) Ligases: These catalyse the joining of two molecules with accompanying hydrolysis of a high energy bond.

CHARACTERISTICS
(1) They are proteins in nature.
(2) They are soluble
(3) Some enzymes require the presence of non-proteinous molecules called co-enzymes to activate them.
(4) Enzymes are specific in action e.g. amylases will only act on starch.
(5) Enzymes are organic catalysts i.e. they speed up chemical reactions in the body but are unchanged at the end of the reaction.
(6) They are affected by the acidity or alkalinity of their surrounding and will only work in specific pH medium.
(7) They have a specific temperature range above or below which they become denatured/ inactive. They work best between 35 to 40ºc.
(8) Enzymes can be inactivated by inhibitors like cyanide and mercury.
(9) They are usually involved in reversible reactions.
(10)Enzymes act in small quantities and catalyses large amount of substrate.
(11)They can function outside organisms producing them.

EVALUATION
1. What is an enzyme?
2. What are the functions of enzymes?
3. Enumerate five characteristics of enzymes.

WEEKEND ASSIGNMENT
OBJECTIVE TEST
1. In the enzymatic reaction, Starch amylase Sugar , Starch is referred to as the
(a) enzyme (b) product (c) reaction mixture (d) substrate
2. In a mammalian tooth, the pulp cavity contains
(a) blood vessels (b) cement (c) enamel (d) pulp
3. The kind of teeth used for tearing food material is
(a) canine (b) incisor (c) molar (d) premolar
4. Dead plants and animals are decomposed by bacteria and fungi into
(a) ammonia (b) amino acids (c) nitrates (d) nitrites
5. The substance required to move food along the intestine is
(a) Carbohydrates (b) Fats and oil (c) Protein (d) Fibre

ESSAY QUESTIONS
1. Distinguish between autotrophic and heterotrophic modes of nutrition
2. Describe the symbiotic mode of nutrition
3. Mention three insectivorous plants and discuss one.

PRE-READING ASSIGNMENT
Read up Basic Ecological Concepts

BASIC ECOLOGICAL CONCEPTS
CONCEPT: 1. Ecological concepts
2. Components of an ecosystem
3. Local biotic communities or biomes

Sub – Topic 1:ECOLOGICAL CONCEPTS
Ecology is the study of living organisms in relation to their environment.
The study deals with the relationship of living organisms with one another and with the environment in which they live. Ecology measures factors affecting the environment; it studies the distribution of living organisms and how they depend on one another and their non-living environment for their survival.
Ecology is divided into two
(i) Autecology which is the study of a single individual organism or a single species of organism and their environment. E.g. the study of Tilapia fish in a particular stream.
(ii) Synecology which is the study of inter–relationships between groups of organisms or species of organisms living together in an area. E.g. the study of all organisms in a particular stream in relation to their environment.

Ecology Concepts
Environment: This refers to all the factors in an organism’s surroundings, living or non-living. The factors include the place where the organism lives and the physical conditions in the place, the food, water and air it takes in, the animals that prey on it and the disease that affect it.

Habitat: This is the place where an organism lives. It is the place that is suitable to the organism’s way of life e.g. the habitat of fish is water.
Examples of habitats include:
Aquatic habitats e.g. puddles, streams, ponds, seas, oceans.
Terrestrial habitats e.g. savanna, rain, forest, desert, etc.
Arboreal habitat i.e. tree tops and tree trunks.

Ecological Niche: This is the functional role and the space / specific portion of habitat occupied by a particular organism or species. E.g. a caterpillar and an aphid may live on the same plant but occupy different positions. The caterpillar lives on the leaves and feeds on them while the aphid lives on the young shoot / stem and sucks sap from it. The functional role includes the organism’s behaviour, its feeding habits and breeding habits i.e. the activities carried out while occupying the spaces in the habitat.

Population: This is the total number of all organisms of the same species or kinds, living together in a given area / habitat. E.g. the total number of Tilapia fish in a pond constitutes the population of Tilapia fish in that habitat.

Community: This is made up of all the populations of living organisms that exist together in a habitat. It is any natural occurring group of different organisms living together and interacting in the same habitat. E.g. the community on a rotting log will include insects like termites, ants, lizards, small birds and decomposers such as bacteria and fungi.

Biosphere: This refers to all parts of the atmosphere, hydrosphere and lithosphere where life can be found. It is the largest and highest level of biological organization and is made up of various ecosystems.

Ecosystem: This is self – supporting unit that is made up of a living part and a non-living part. It is a community of plants and animals interacting with themselves and with the non-living factors in their environment.


EVALUATION
1. Define ecology
2. Mention four ecological concepts and explain them

Sub- Topic 2: COMPONENTS OF AN ECOSYSTEM
The living part of the ecosystem is called its biotic component while the non-living parts are called the biotic component.

(a) Biotic component: This includes all living things/organisms in an environment. It is also called the biotic community. It is made up of;
Food producer’s e.g. autotrophs (green plants), chemosynthetic bacteria and protophyta.
Food consumer’s i.e. heterotrophs such as animals, protozoa and some bacteria.
Decomposer’s i.e. saprophytes like fungi and some bacteria.

(b) Abiotic component: This consists of abiotic resources and abiotic conditions
Abiotic resources: These are what organisms need so as to stay alive. E.g. sunlight (a source of energy) and inorganic nutrients like water, nitrogen, carbon dioxide, phosphorus etc.

Abiotic conditions: These are those factors that determine the kind of organisms that are found in a particular ecosystem. These factors affect the behaviour, growth and breeding patterns of organisms, they include;
(a) Climatic factors such as temperature, wind, light intensity, humidity, water currents, turbidity, rainfall, e.t.c.
(b) Edaphic factors such as soils, rocks, topography, etc.
(c) other factors like air, water, storms, etc.

Characteristics of An Ecosystem
The characteristics which make an ecosystem a functional unit/a self–supporting unit are
(i) a flow of energy
(ii) a recycling of inorganic nutrients.
The major interaction between the biotic and abiotic components involves
feeding. Food producers like plants, trap sun-light energy and nutrients (e.g.
carbon dioxide, nitrogen) etc. from the abiotic environment to make food. The
energy and nutrients in the food is passed on to heterotrophs (consumers) such
as animals which feed on plants or on one another. The animals and plants
eventually die and decomposers feed on them thereby obtaining their own
energy. However in the process, the decomposers release the nutrients in the
animals and plants back into the abiotic environment (i.e. the soil). These
nutrients can be re-used again by the food producer’s. Plants also give out
oxygen during photosynthesis and this is used by animals for respiration.
Animals give off carbon dioxide during respiration which plants take up.

NB: As the energy in food is passed from one organism to another it eventually
escapes into the environment and cannot be re-used.

EVALUATION
1. Define (a) biotic factor (b) abiotic factor
2. Give two examples each of the concepts defined above
3. What characteristics make an ecosystem a self- supporting unit.


Sub – Topic 3: BIOMES
Biomes are large natural terrestrial (land) ecosystems. It is the
largest community of organisms interacting with the non-living environment.
Biomes are identified by their vegetation. Examples include forest, desert,
savannas, etc. The type of vegetation is largely determined by climatic factors
especially rainfall and temperature, as such, regions in the world which have
similar climates also have similar biomes.

Local Biomes In Nigeria
This can be grouped into two major zones
(1) The forest zone (2) Savanna zone

(1) The forest zone: This is made up of vegetations having mainly trees, they
include:
(a) Mangrove swamp: A forest of tall woody trees with aerial roots. The
rainfall is high and the soil is water logged throughout the year.
Plants here include the white and red mangroves, raffia palms and coconut.
Found in states like the Delta, Cross River, Bayelsa etc. The climate is hot and wet throughout the year. Rainfall is heavy usually above 2500mm and the average monthly
temperature is around 26ºc for most months of the year.

(b) Tropical Rainforest: Consists of tall trees with buttress roots, with evergreen and broad leaves. The trees exist in canopies i.e. different layers, and prevent sunlight from reaching the forest floor, thus the vegetation on the forest floor is sparse. Epiphytes and climbers are common features in the trees.
The climate is hot and wet throughout the year. The mean annual temperature is 27ºc while the mean total annual rainfall is 2000mm. These forests are found in states like Oyo, Edo, Cross River, Ogun, Ondo, Imo and Rivers State.

(2) Savanna zone: This is made up mainly of grasses and includes;
(a) Southern Guinea Savanna: Consists mainly of tall grasses, with a few tall trees with broad leaves. The trees are scattered and deciduous. Examples include the locust beans trees, shear-butter and isobelina.
It has a moderate rainfall of between 100-150cm per annum. They are located in Enugu, Kogi, Benue, Kwara, Osun, Oyo, Ebonyi, and Ekiti States.

(b) Northern Guinea Savanna (Sudan Savanna): This has short but numerous grasses. The trees are scattered, short and deciduous. The trees have thorns while others have thick barks. The trees include acacia, date palm, baobab and silk cotton plants.
The rainfall is low, about 50-100cm per annum. They may be found in states like plateau, Kaduna, Bauchi, Niger, Taraba, Adamawa and Kano.

(c) Sahel Savanna: It has very short and scanty grasses. There are short and tough shrubs or trees. The plants are mainly drought resistant and scattered examples include acacia, gum arabic and date palm.
The temperature is very high and rainfall is very low, below 50cm per annum. It may be found in States like Bornu, Katsina, Sokoto, Yobe, Kebbi, Zamfara, Kano and Jigawa.

EVALUATION
1. What is a biome and how can it be identified?
2. Mention the two major biomes in Nigeria and the types

WEEKEND ASSIGNMENT
OBJECTIVE TEST
1. Epiphytes are usually found in (a) grassland (b) desert (c) forest (d) marsh land
2. The highest amount of rainfall is recorded in (a) Rainforest (b) Mangrove swamp
(c) savanna (d) desert
3. The Sahel savanna is found in …….. state of Nigeria (a) Akwa Ibom (b) Kogi
(c) plateau (d) Zamfara
4. Most trees in the savanna region (a) have buttress roots (b) have pneumatophores
(c) are deciduous (d) are ever green
5. Which of the following is not an abiotic factor? (a) air (b) food (c) light (d) water

ESSAY QUESTIONS
Make a drawing of the map of Nigeria and outline the local biomes

PRE-READING ASSIGNMENT
Read up The Biomes of the World

TOPIC: BASIC ECOLOGICAL CONCEPTS
CONTENT: 1. Major biomes of the world
2. Population studies by sampling method
3. Ecological factors
4. Simple measurement of ecological factors
5. Relationship between soil types and water holding effects of soil
on vegetation

Sub – Topic 1: MAJOR BIOMES OF THE WORLD
Zones of different biomes occur from the equator to the arctic and to the
antarctic due to differences in climate. In the equatorial and tropical areas where
temperature and rainfall are high all year round, tropical forests occur while in
the cold arctic regions, treeless plains called tundra are found.
Climates change with distance from the equator and also with height above sea level, as such
zones of different biomes occur from the equator to the poles and on a mountain side.

Examples of major biomes of the world
(1) Tropical rain forests: These consist of dense forests with many types of
trees, epiphytes and climbers. Rainfall is abundant throughout the year and an
average temperature of 27ºc is recorded throughout the year.
Located around the equator e.g. around coasts of West Africa, Amazon basin of South Africa, etc.

(2) Temperate forests: These consist of broad-leaved deciduous trees which
shed their leaves during winter. A lot of different plants grow at many levels from
the ground as the trees are not densely packed as in the tropical forest. It has a
moderately wet climate and a dry or cold season. Examples are found in North
America, lowlands of North – West Europe (e.g. France), and Britain.

(3) Coniferous forest: These consist of needle leaved, evergreen conifers e.g.
pines, fires and spruces. Only a few types of tree are found in these forests.
Other plants such as shrubs, ferns and mosses are also present. The temperature
is cool and rainfall is light. There is also light snow. Examples are found in
Eurasia and North America.

(4) Temperate shrubland: Consist of drought-resistant shrubs, aromatic plants
and dwarf trees. The temperature is very high (over 30ºc), rainfall is low, the
summers are hot and dry and the winters are mild and rainy. Examples are
found in North-Eastern Brazil, Australia, and close to the Sahara in West Africa.

(5) Savanna: These are tropical grasslands with few scattered trees. It has a
moderately dry climate, a warm dry season and a hot rainy season. Examples
are found in Central America, Interior of Brazil, West Africa, East Africa, and
South-East Asia.

(6) Temperate grassland: Consist of large stretches of perennial grasses growing
on very fertile soil. Examples are the steppes, prairies, plains, pampas and veld.
The climate is moderately dry with a cold winter and hot summer. Examples are
Found in the interior continents in Asia, North America, South America,
(Argentina), South Africa and Australia.

(7) Desert: Consist of very sparse vegetation which are mainly succulent
perennials with deep root systems and annuals which exist mainly as seeds,
germinate and grow rapidly, flower and produce seeds during brief periods of
rain.
Rainfall is very low and temperature is very high. E.g. Sahara desert
(North Africa), Arabian Desert (Arabia), e.t.c.

(8) Tundra: Consists of treeless marshy vegetation composed mainly of dwarf
shrubs, grasses, sedges, lichen and moss. The climate is clod with long icy
winters and very short summers. The average temperature is 10ºc. Examples are
the coastal strip of Greenland, Northern Canada and Alaska, Arctic seaboard of
Eurasia.

(9) Mountain vegetation: Consist of evergreen rain forest occurring on the
slopes of mountains. The forests are less luxuriant than the tropical rain forest.
The Afro-alpine vegetation occurs at height above 3000m on mountains. The
vegetation consist mainly of heaths, grasses and sedges. In Africa it is found in
Cameroon mountain, Kenya highland and Kilimanjaro mountain. Temperature
decrease with altitude. Rainfall is heavy on the windward side and less on the
leeward side of the mountains.


EVALUATION
1. List six biomes of the world
2. Briefly discuss two biomes of the world.

Sub – Topic 2: POPULATION STUDIES
A population is defined as the total number of organisms of the same species
living together in a given area at a particular time.
In any ecosystem, the community is made up of many populations of different
species.
To study a habitat’s populations, the following are usually investigated.
1. The type of organisms in the habitat: This involves listing all the different types of populations found in that particular habitat. This helps to determine the relationships that exist between the different organisms in the habitat.

2. The dominant species: This refers to the species of organisms in a community which exert a great influence on the habitat and on the other populations. Dominance may be expressed in terms of their number, size, the portion of space occupied and contribution to the energy flow of the habitat.

3. The characteristics of the population: This refers to;
(a) Population size: The total number of individuals of the same species in the habitat (the total numbers of individuals in a population). A large population stands a better chance of surviving unfavourable conditions such as fires, diseases, harsh climate changes, while a small population can be easily wiped out. A large population also has the advantage of increasing its vigour through breeding which invariably increases its ability to withstand adverse conditions.
(b) Population density: This is defined as the number of individual organisms per unit area or volume of the habitat.
Mathematically represented as;
Population density = Total population or Population size
Area of habitat.

Example: If an area of land of 100m² has an elephant grass population of 1000 plants, the density of elephant grasses will be;
Total number of individuals
Total area

= 1000 elephant grasses
100m²

= 1OØØ elephant grasses
1ØØm²

= 10 elephant grasses / m²

Population density can be used to estimate the total number of individuals of a population i.e. population size.
(c) Population frequency: This refers to how often the species occurs at different sites in its habitat. It is recorded as the number of times the organism is sited (seen).
(d) Population growth rate: This refers to the total and final effect of birthrate and death rate of organisms in the habitat.
(e) Percentage cover: This is the area of ground or space covered (or occupied) by a given species its habitat. It is expressed in percentage.
(f) Distribution: This refers to the way in which individuals of a particular population are arranged in a given habitat. The individuals may live in clumps, they may be evenly spaced or randomly spaced.
Example: If the western half of the habitat contained ¾ of the elephant grasses, then,
Density = ¾ x 1000 = 75Ø = 15 grasses / m²
5Ø

Methods Of Studying Populations
-To conduct population studies the following procedure is used;
-Choose the habitat to be studied
-Choose a sampling method
-Identify the species in the habitat
-Collect, count and record the different types of organisms present.
-Repeat the population studies at different periods.

The following methods can be used to study specific populations;
1. Collection of plants: In a small area plants are easy to count and their distribution can be recorded on a map or scale diagram of the area, however for larger areas quadrates or transects are used.
(a) Quadrat Sampling: A quadrat is made of a square or rectangular piece of wire, plastic, wood or metal frame with predetermined area. E.g. the area of a quadrat may be 25cm². A quadrat is used to sample the number of plant species in a habitat. It is not suitable for sampling animals because they move around so much. A quadrat is used by throwing it over the shoulder at random several times and on each landing, the area covered/enclosed by it is observed. The type of plant species and their number within the quadrat are recorded. From the results, the average number of plant per m² is calculated. If the area of the habitat is known, the total number of plants it contains can be estimated.
Permanent quadrats, with mapping grids attached can be made to study seasonal variations of plants. These quadrats are sturdier, larger and remain permanently fixed on a marked area.
(b) Transect method: A marked tape is used in this method. The tape is marked at convenient intervals and then stretched across the area to be studied. The plants encountered at the interval marks are counted and recorded. This procedure is repeated a few times. In this way, a fairly accurate estimate of the number and types of plants in the habitat are obtained. Plants are usually collected in plastic bags and then pressed and dried in a plant press. The dried plants are mounted on stiff paper, fixed in position with masking tape/cellotape and labeled with both the scientific and common names.

(2) Collection of Animals: Animals are more difficult to collect than plants; however their presence can be inferred by looking for signs of their presence such as nests, eggs, feaces, tracks, feathers, etc and by studying the vegetation with which they are associated. To study animals different types of nets and traps are used in capturing them. The following methods can be used.
(a) Capture - Recapture method: In this method animals of one type in a particular area are caught, counted and marked with ink and released. Their number is recorded as A1. The following day another set is captured and the number recorded as A2.This second batch may include animals which had been caught and marked the previous day, their number is recorded as A3. The population of animals present in the area is found using the formula;
Population in area = A1 x A2
A3
This method is based on the assumptions that;
Individuals do not move out of or into the ecosystem
The marked individuals are randomly distributed in the population.
The marked individuals are a random sample.
The initial capture and markings do not influence recapture.
That none of the marks have worn off during the interval between the two catches.
NB : The results obtained by this method are approximations.

(b) Collection of soil animals with quadrats: The soil animals in an area can be studied by collecting samples of soil from several sites chosen by tossing a quadrat randomly. A 25% sodium chloride solution is added to each soil sample and the animals are collected as they float in the solution.
For earthworms, the sites chosen with the quadrat are irrigated with 25% formalin solution and the earthworms are collected as they move to the surface of the soil.

EVALUATION
1. What are the major investigations carried out when studying a habitat?
2. A pond with an area of 200m² has a duckweed population of 1,500 plants. Find
(a) The population density
(b) If the western half of the habitat contained ¾ of the duckweed. What is the density of the eastern half?
3. Explain what a Tullgren’s funnel is and what it is used for.
4. Make a list of traps used for capturing animals for study and describe how captured animals are kept or preserved.

Factors That Affect Populations
Populations in a habitat may show changes in size or distribution. These
changes may be due to;
1. Natality (birth rate): Increase in birth rates especially during breeding periods, lead to increase in population size while a decrease in birth rate results in a decrease in the population.
2. Mortality (death rate): This refers to the rate at which organisms die. An increase in death rate leads to a decrease in the population and vice versa.
3. Immigration: This is the movement of organisms from different habitats into a particular habitat. This increases the population size of the habitat being moved into.
4. Emigration: It is the movement of organisms out of a habitat ant it leads to a decrease in the population. Emigration may be caused by scarcity of food, unfavourable conditions, seasonal climate changes or breeding purposes.
5.Availability of food: An abundance of food in a habitat tends to lead to an increase in the population of organisms due to increase in birth rate (reproduction) and influx of organism from other areas and vice versa.
6. Seasonal climate changes: Adverse climate changes may lead to a decrease in number of organisms due to death or emigration. Favourable conditions leads to an increase in population.
7. Natural disasters e.g. fire; flood, drought etc. may lead to a decrease in population due to death and emigration.

SUGGESTED ACTIVITY
Set up a small ecosystem making use of a large plain glass container/ empty aquarium. Observe your ecosystem for 2-3 months

Sub –Topic 3: Ecological Factors
These are factors in the environment that influence life in the ecosystem. These factors affect the living organisms or cause changes in the habitat (aquatic or terrestrial). These factors are grouped into two (i) Biotic factors (ii) Abiotic factors. The biotic factors are those concerned with the effects of plants and animals on one another in a given habitat e.g. competition, predation parasitism, etc. Abiotic factors include climate topographic (or physiographic) and edaptic (soil factors). Variations in the ecological factors bring about changes in the habitat. Abiotic factors also determine the type of biotic community found in a habitat.

Ecological Factors Affecting Terrestrial Habitats
(1) Topographic Factors: These factors are associated with the structure of the habitats e.g. effects of hilts, valleys, plains mountains and rivers. These factors bring about variation in the vegetation and types of animals in an area.
Topographic factors include:
(a) Altitude (elevation): This refers to height of the land above sea level. This affects the growth of plants and the level of erosion in an area. As altitude increases, temperature falls by approximately 1ºc per 150metres, as a result of this, mountain tops are generally cold places cold air causes clouds to condense and fall as rain, thus the annual rainfall on mountains is high especially on the windward side. As one ascends a mountain, the air become less dense, there is less of it to filter the sun’s rays, so organisms at the top of mountains are exposed to intense solar radiation.
(b) Slope: Water flows faster on a steep slope than on a gentle slope as such, run-off is greater and less water sinks into the soil on steep slopes. Also, erosion tends to be more. Gentle slopes are more favourable to plant growth.
(c) Exposure: This refers to the extent to which living things are not protected from climatic factors such as rainfall, sunshine and wind. Exposure is usually high on mountains and low within a forest. Winds tend to be stronger in exposed habitats and relative humidity is lower than in sheltered habitats. Low degree of exposure ensures the availability of nutrients to plants.

(2) Edaphic Factors: These are factors related to the nature of soil particles. The word edaptic refers to the influence of soils on plants and animals. Differences in the soil of a locality usually produce difference in vegetation since plants are dependent on the soil and the type of plants determine the type of animals that will be found in the habitat. Edaphic factors include:
(a) Soil Types: this could be sand, loam or clay. The type of soil determines the fertility of the soil, its porosity and water retaining capacity.
(b) Soil Texture: The amount of sand, silt and clay in a soil affects its water retaining capacity. Soil texture refers to the degree of fineness or coarseness of soil particles. It also affects leaching and erosion.
(c) Soil structure: This refers to the arrangement of the various soil particles in soil. This affects the level of soil aeration and percolation and the type and level of soil organisms in the soil.
(d) Soil pH: The pH of soil also affects the type of plants in the habitat e.g. some plants grow best in acid soils while others prefer alkaline conditions.
(3) Relative Humility: This is a measure of the amount of moisture in the air. It affects the rate of transpiration from plants and evaporation from animals. As relative humidity falls, evaporation and transpiration rise as such organisms that live in areas where humidity is low must prevent water loss from their body surfaces. E.g. in deserts, the leaves of plants like the cactus are reduced to spines to prevent loss of water.

Ecological Factors That Affect Aquatic Habitats
(1) Salinity: This refers to the concentration of salts in the water. Salinity affects the movement of water and salts across the body tissues of aquatic organisms. Salinity is low in fresh water, high in sea water and moderate in brackish water. Aquatic organisms have to maintain the osmotic balance between their body fluids and their aquatic surroundings in order to survive. Those living in fresh water have adaptive features which enable them get rid of excess water that enters their bodies; those living in sea water have body fluids with almost the same salt concentration as the sea water while those living in brackish water have body tissues that can tolerate wide and sudden fluctuations in salt concentration of their body fluids.

(2) Depth Of Water: As a body of water becomes deeper, the amount of light and dissolved oxygen become less, so at the bottom of deep lakes and oceans, there may be too little light for photosynthesis as such no green plants can grow there. Shallow bodies of water such as ponds are usually well supplied with oxygen and light and support a lot of plants and animals. However, these habitats are subject to evaporation and drying up in the dry seasons, the plants and animals therefore have to develop adaptation to survive such conditions. E.g. formation of cysts by some protozoans.

(3) Turbidity: This refers to cloudiness of water. It is caused as a result of suspended materials in water. Light penetration is low in cloudy or muddy water and this hinders green plants from growing at some depths.

(4) Dissolved Gases: This refers to dissolved oxygen. Oxygen concentration of water decreases with depth. Oxygen is required by most aquatic organisms for respiration as such organisms which live in stagnant or very deep water have to be able to tolerate low levels of oxygen concentration. Organisms that require high oxygen concentration, usually live near the surface of deep water or in fast-flowing rivers and streams e.g. the simulium larva lives in fast flowing streams.

(5) Tides and Wave Action: Tidal movement refers to the regular rise and fall in the level of the sea. Organisms which live in the intertidal zone of a seashore have to be able to tolerate being alternately covered by sea-water and then exposed to air twice daily.
Wave action is also important both in the intertidal and splash zones of the seashore. Most organisms in these areas are attached to the substratum or live in burrows. Some attach themselves firmly to rocks and other immovable objects, while some others have hard body covering to prevent evaporation of water from their bodies. Waves cause the aeration of the surface waters of the open sea, thus enabling aquatic organisms to have sufficient supply of dissolved gases for their needs.

(6) Speed of Flow (currents): Plants and animals are affected by the rate at which the water flow. Some organism’s e.g. spirogyra prefer to live in slow moving stagnant water while others e.g. Tilapia, prefer fast-flowing water. Many organisms which live in fast-flowing rivers and streams have adaptations which serve to prevent them from being swept away from their support by currents in water. Water currents increase aeration and the turbidity of the water. Currents also carry warm water to colder regions and this affects the distribution of organisms.

(7) Density: Density of water varies with the type of habitat. The density of fresh water is about 1.00 while that of sea water is 1.028 at atmospheric pressure and 0ºc. It is easier to move through air than water because water is more dense, as such aquatic organisms have a streamlined shape to help them move easily through water. Some organisms that float on the surface are sensitive to changes in density e.g. eggs of aquatic organisms sink to different depths depending on the density of the water.

Ecological Factors Common To All Habitats
The ecological factors that affect both the terrestrial and aquatic habitats are mainly climatic e.g. temperature, rainfall, relative humidity, wind, high intensity hydrogen ion concentration (pH) and pressure. Of these factors temperature and rainfall determine the type of vegetation in a region.

(1) Temperature: This refers to degree of hotness or coldness. Variation in temperature results in hot or cold climate. It affects the terrestrial habitat more than the aquatic habitat. In the terrestrial habitat temperature varies with season, while in the aquatic habitat it decreases with depth.
A rise in temperature usually results in a higher rate of transpiration in plants and higher rate of metabolism in most animals (except homoiotherms). Most living organisms are killed by high temperatures and it reduces the performance of some. Low temperatures lead to inactivity or dormancy. In some organisms (e.g. tadpoles, insect larvae and bacteria) a rise in temperature results in faster rate of growth and shorter length of life-cycle. A higher rate of evaporation of water from the soil, ponds and lakes and a lower relative humidity are also observed.
Too high or too low temperature inhibits the growth and life activities of living things. However most organisms have various adaptive features that allow them to live at low or high temperatures e.g. Bears living in the arctic regions have very thick furs.

(2) Rainfall: Rain is the main source of water to most organisms. It also supplies water to soil on which land plants depends. It is also the major source of water in rivers, ponds, lakes, oceans etc. The amount of rainfall in an area has a major effect on the type of vegetation found there. Low amount of rainfall usually causes drought on land and drying up of freshwater habitats (which leads to death of animals). Too much rain causes floods and destruction of vegetation through erosion.
Rainfall increases relative humidity and also increases turbidity of streams, rivers and lakes. Rainfall is necessary for seed germination. It helps to dissolve nutrients in the soil thus making them available to plants. It is also necessary for the vegetative growth of most crops e.g. flowering and proper development of groundnut pods.
Rain water may form puddles and small pools which provide temporary habitats for mosquito larvae, algae and tadpoles. It is also necessary for the start of new termite colonies.

(3) Light: Light is necessary for photosynthesis in green plants. It affects the productivity of crops and facilitates flowering and fruiting in some plants. Light is the ultimate source of energy for all organisms. Light affects the activities of animals e.g. some animals are active during the day (butterfly) while others are active at night (cockroaches). The ultra-violet rays of the sun enable animals to manufacture vitamin D.

(4) Wind: Winds are important because they cause water currents and waves thus mixing water and making food available in aquatic habitat, Winds carry rain bearing clouds. They also determine a season e.g. In Nigeria, the S/W wind is responsible for the rainy season while the N/E wind brings the harmattan. Wind has drying effects (on land) and so it increases the rate of transpiration in plants. In an area exposed to strong winds only xerophytes can grow there. Winds also aid pollination of flowers and dispersal of seeds and fruits. Winds increase the rate of evaporation from the soil and in savanna and desert areas it is a major cause of soil erosion. Winds also play an important role in the establishment of insects in a given area.

(5) Pressure: Atmospheric pressure decreases from the depths of the ocean upwards to the higher attitude of the atmosphere. Plants and animals have special adaptations to a particular level of pressure to enable them survive. For instance in the oceans, the pressure increases by 1.03kg/m² every 10m, so organisms found at depths of about 400m live in conditions of enormous pressure but are well adapted to such conditions and will not survive at levels with lower pressure.

(6) Hydrogen ion Concentration (pH): This refers to the acidity or alkalinity of the soil or water in a habitat. pH affects the types of plants and animals in a habitat. E.g. some plants grow best in acidic conditions while others can only grow in alkaline conditions. In aquatic habitats pH varies with the salinity of the water. Freshwater is neutral while sea water is fairly alkaline (pH 8.5). Organisms like the freshwater mollusks (Mytilus) are usually absent in water with a pH less than 6 (i.e. acidic water).

Biotic Factors Affecting the Ecosystem
Biotic factors refer to the effects of plants and animals on themselves or one another. The biotic factors include:
(1) Parasitism: One organism called the parasite lives in or on another organism called the host. The parasite benefits while the host suffers harm or may die.

(2) Competition: This may occur between organisms of the same species or different species. Competition may be for food, space, mates, etc. One of the organisms will eventually over come the other.

(3) Commensalism: This involves two organisms living together. One of the organisms (the commensal) benefits from the association while the other organism neither benefits nor is harmed.

(4) Predation: This involves an organism (called the predator), killing / feeding on another organism (the prey).

(5) Trampling: Grazing animals trample on plants and invertebrates.

(6) Pollination of flowers by insects (this aids continuity and increase).

(7) Aeration of the soil by some animals e.g. earthworms, termites, etc.

(8) Support provided to climbing plants by trees or bigger plants.

(9) Shade provided by trees, etc.

Evaluation
1. State five ecological factors that (a) affect terrestrial habitats (b) affect aquatic habitats (c) are common to both habitats
2. Discuss two of each set of factors mentioned above.

Sub – Topic 4: SIMPLE MEASUREMENT OF ECOLOGICAL FACTORS
(1) Temperature: This is measured using a mercury thermometer read in degree celcius (ºc). At least two readings are taken in a particular area of the habitat being studied to ensure accuracy. A soil thermometer is used for soil temperature, a maximum-minimum thermometer for recording the highest and lowest temperature of the day, and a waxed bulb thermometer for temperature of water at different depths in a pond, stream, etc. The waxed bulb thermometer is usually tied to a string knotted at regular intervals to indicate depth.



Outdoor thermometer Thermometers



(2) Rainfall: This is measured with a rain gauge. This can be made from a tin can, a plastic funnel and a 50ml measuring cylinder. The amount of rainfall is calculated in millimeters, with the formula

d
D²x h = rainfall for a period where;

d = diameter of mouth of funnel
h = height of rainwater in the cylinder
D = diameter of collecting cylinder

Usually, the height of the water in the cylinder indicates the amount of rainfall after every storm.

(3) Relative Humidity: Is measured using a wet and dry bulb hygrometer, or a pocket hygrometer. The pocket hygrometer is exposed to air and the reading taken after the lever arm has stabilized. The wet and dry bulb hygrometer is swung in air for 30seconds and the reading on the thermometers taken and converted to relative humidity units using a table of conversion. The hygrometer may also be kept in a Stevenson’s screen.

(4) Wind: Wind has both speed and direction. Wind direction is measured / indicated by a wind vane while wind speed is measured with an anemometer (recorded in ms־¹).

(5) Light Intensity: Is measured by a light meter or photometer. The readings on the meter are expressed in lux units. The greater the intensity of light, the higher the readings on the meter and vice-versa.

(6) Pressure: Atmospheric pressure is measured with a barometer. It is measured in millibars (or millimeters of mercury, mmHg). The readings are taken directly from a scale.




Aneroid barometer Mercury barometer



(7) Water Depth: Is measured with a meter rule or a marked and weighted line knotted at one meter intervals. The meter rule is attached to a weighted line to ensure that it is vertical in water.

(8) Water Flow: To measure the speed of flow of a water body, the distance (m) covered per unit times by a float is taken. The float may be a weight tube and the distance covered has to be pre-determined. Speed of the current is calculated in meters per second. A simple water-speed meter can be used to compare the speed of water flow at different positions in a stream

(9) Turbidity: Is measured by slowly sinking a weighted white disc called a secchi disc into the water, noting the depth at which it just cannot be seen anymore. This is not a real measurement of turbidity but a useful method of comparing the turbidity of different aquatic habitats, different sites of the same habitats, or at different times.

(10) Slope: Is measured with a simple slope gauge constructed with a meter rule to which a protractor is attached. The angle readings on the protractor are read and recorded. Small angles indicate a steep slope.

(11) Height: The height of objects like tall trees is measured using the principle of similar triangles.

EVALUATION
State five ecological factors and describe how they are measured.

Sub – Topic 5: RELATIONSHIP BETWEEN SOIL TYPES AND WATER HOLDING EFFECTS OF SOIL ON VEGETATION
Soil is the uppermost layer of the earth’s crust which provides support and nutrient for plants growth and habitat for some animals. The soil is a complete mixture of mineral matter, humus, air and living organisms. Soil is classified on the basis of the size of the particles present in it. Soil particles vary in size and chemical composition, depending on the types of rock from which they were formed and how they were weathered. Those soils with a high proportion of sand are known as sandy soils; those with a high proportion of clay and silt are called clayey soils and those with nearly equal amount of sand, clay and silt are known as loamy soils. The proportions of these particles in the soil have an important effect on their properties and on the types of plants found on them.

Types of Soil
(1) Sandy Soil: This contains 80% sand and gravel and 20% of the other types of particles taken together. Large coarse particles of sand and gravel predominate.

(2) Clay Soil: This contains more fine clay (60%) and silt particles.

(3) Loamy Soil: This contains a mixture of both clay and sand with some humus in roughly equal proportion. Loamy soils are the most fertile and the humus in it gives it a mellow tilth i.e. the size of the soil particles and the air spaces between the particles are the most suitable for cultivation.

Effects of Soil On Vegetation
Soil factors play an important role in determining the vegetation of a region. Soils account for the variation in type of plants that are found in regions with similar climates. To support a rich growth of plants, soil must have the following characteristic;
(i) A rich humus content
(ii) A rich mineral content
(iii) A good water-holding capacity; this is determined by the amount of humus and clay in it.
(iv) Good soil porosity; determined by the humus, sand content and soil texture.
Sandy soil is low in plant nutrient and so it supports scanty vegetation or grassland. Clay soil has a little more amount of plants nutrients than sandy soils and thus can support light vegetation such as shrubs. Loamy soil is very fertile and can support luxuriant vegetations such as a forest.

Water-Holding Capacity of Soil
Water holding capacity of soil refers to the ability of the soil to retain water. The amount of water retained by any soil depends or the size of the particles, the humus content, aeration, temperature and presence of microbes. Clay and humus retain a higher amount of the water than sand. In clay soil, most of the water is held firmly to the surface of the soil particles (hygroscopic water) and this is not usually available to plants. In sandy soil very little amount of water is retained as most of it drains off. Loamy soil is able to retain more water within its particles. This is called capillary water and is available for plants use.

SUGGESTED PRACTICALS

1. Experiment to Determine The Water Retaining Capacity of Soil Types
Title of experiment: To compare the porosity and water holding capacity of three soil types
Materials required: Three measuring cylinders of 100cm³, cotton wool, three funnels, water, dry sand, dry clay, dry loam, stop clock, balance.
Method: Stand the three funnels in the three measuring cylinders and block the funnels with cotton wool.
- Place an equal weight of dry sand, dry clay and dry loam in the three funnels respectively.
- Pour 50ml of water onto each sample at the same time and allow to drain.
- Allow the set up to stand for an hour or until the water has stopped dripping through each funnel.
- Read the level of water in the measuring cylinder.
Calculations:
(a) Rate of drainage / porosity is calculated from the amount of water collected in the measuring cylinder. The more the water, the more porous the soil sample. Usually porosity is highest in sandy soil because it has large pore spaces and large particle sizes, followed by loamy soil and then clay soil which has the least drainage because of its tiny pore spaces and fine particles .
(b) Water holding / retaining capacity is calculated as follows;
Volume of water added to soil = 50ml
Volume of water collected in cylinder = xml
Volume of water retained in the soil = (50-x) ml
The percentage of water retained in each of the soil samples will be
(50-x) x 100 = Y%
50
Observation: It is observed that water drained out from the sandy soil faster than the loamy soil and finally the clay soil. It was also observed that clayey soil retained more water than loamy soil and least retained by the sandy soil.
Conclusion: Sandy soil is more porous than loam which is more porous than clay. Clayey soil retained more water than the loamy soil and the sandy soil retained the least amount of water.

2. Experment To Compare The Capillary Action Of Soil Types
-Take three wide glass tubes and plug each at one end with cotton wool.
- Nearly fill the tubes with the three soil samples separately.
- Clamp the tubes upright in a trough of water,
- Allow the set-up to remain for 3-6 hours
- Observe every 30mins.
Observation: It will be observed that at the early stage of the rise of water in the three tubes, it was faster in sandy soil than the clay and loamy soil samples, however by the end of the experiment the water had risen to the highest levels in loam, followed by clay but remained at a low level in the sandy soil.
Conclusion: Loamy and clayey soils have greater capillary actions due to their tiny pore spaces. The presence of organic matter in loam also enhanced its capillary. The sandy soil had poor capillary action because of its large pore spaces and large particles.

EVALUATION
1. List the three major soil types.
2. Discuss the constituents of the soil types mentioned.
3. Compare the water holding capacities of the three soil types.

WEEKEND ASSIGNMENT

OBJECTIVE TEST
1. The distribution of plants in a rain forest is governed mainly by ……..(a) amount of sunliught (b) rainfall pattern (c) soil type (d) vegetation
2. The turbidity of a water body can be measured using (a) hygrometer (b) light meter (c) rain guage (d) secchi disc
3. The number of organisms of a particular species is termed ………(a) community (b) ecosystem (c) synecology (d) population
4. All these are ecological factors affecting all habitats except ……(a) humidity (b) rainfall (c) temperature (d) wind
5. Which of the following world biomes is strictly mountain vegetation? (a) Afro-alpine (b) deciduous forest (c) Mangrove (d) savanna.

ESSAY QUESTION
(1) Describe how the height of a forest tree can be measured.
(2) In a table outline the properties/characteristics of the three major soil types (at least ten properties)
(3) Make large well labeled drawings of a maximum and minimum thermometer; a rain gauge, a wind vane, an anemometer, a light meter, a secchi disc, a barometer and a slope gauge.

PRE READING ASSIGNMENT
Read up The Functioning Ecosystem

TOPIC: FUNCTIONAL ECOSYSTEM
CONTENT: (a) Autotrophy and Heterotrophy (i) Producers (ii) Consumers (iii) Aquatic and Terrestrial
In this topic, the question a wise student will ask is; what is ecosystem? First of all, the word ‘eco’ simply means ecology so, it is ecological system. Let us consider this illustration, in a freshwater habitat where you have aquatic plant such as spirogyra, animals such as tilapia, frogs and toads. All this living things interact with the non- living environment which includes the water where they are, the atmosphere, and the soil beneath it. These living things in the environment together with the non-living environment constitute an ecological system or ecosystem.
Therefore, an ecosystem is defined as the interrelationship between the living things and their non-living environment
COMPONENTS OF AN ECOSYSTEM: Autotrophs and Heterotrophs.
In an ecosystem, there are two major parts; the biotic or living and abiotic or non-living part. Then from the functional point of view, we have three kinds as producers, consumers, and decomposers. The producers are always green plants; the consumers are the animals, while the decomposers are the saprophytes.
Now, under the consumers we have the following:
1. Primary consumers, e.g. grasshopper, rat etc.
2. Secondary consumers, e.g. cat, lizard etc.
3. Tertiary consumer, e.g. hawks, snakes.
4. Omnivores, e.g. man, domestic fowl.
Decomposers are organisms which feed on the carcasses of dead producers and consumers and in the process bring about the decay of such carcasses. Large decomposers such as insects and earthworms are called macro decomposers, whereas small decomposers, such as certain bacteria and fungi are known as micro decomposers.
SOME PRODUCTS OF DECOMPOSITION
In the process of decomposition, dead organic matter is broken down physically and chemically, and this is done in stages. Now, the product of this decomposition is inorganic compounds like carbon (iv) oxide, ammonium, ammonium compound as well as salts of elements present in the organic matter. Some gaseous products such as carbon (iv) oxide, ammonia and hydrogen sulphide can be identified as organic matter decomposes. Intermediate products of decomposition include sugars, and complex organic compound derived from protein.
ROLE OF DECOMPOSERS
The role of decomposers is the recycling conversion of materials of dead organic materials into inorganic materials which are available to the producers in the ecosystem.

Coral Reef in the Red Sea
Coral reefs represent the most complex aquatic ecosystem found on Earth. Although coral reefs can be found between 30 degrees north and south latitude, the greatest concentration is found between 4 degrees north and south latitude in the western portions of all major oceans. There are two broad categories of coral reefs: shelf reefs and oceanic reefs. Shelf reefs include fringing reefs, platform reefs, bank reefs, and barrier reefs and are located on the continental shelf, while oceanic reefs are found off the continental shelf growing around the margins of volcanic islands. Coral reefs support greater numbers of fish and invertebrate species than any other ecosystem in the ocean.
Evaluation
1. Define the term ecosystem.
2. List the two major parts of the ecological system
3. Outline four classes of consumer with on example each.
4. Write the two types of decomposers.
GENERAL EVALUATION
OBJECTIVE TEST:
1. A domestic fowl belong to (a) omnivores (b) quaternary consumer (c) primary consumer (d) secondary consumer (e) tertiary consumer.
2. Some gaseous products of decomposition include all of these except (a) ammonium Chloride (b) carbon (iv) oxide (c) ammonium (d) hydrogen sulphide (e) hydrogen oxide.
ESSAY QUESTIONS
1. Give an instance in writing to show how living things interact with their non living environment.

WEEKEND ASSIGNMENT
Sketch the organogram of the ecosystem
Find out the group of consumers the Carnivores belong.
PRE-READING ASSIGNMENT
1. Read Senior Secondary Biology 1 by F.O.C. Ndu et-al (pages 128-129), and categorise the product of decomposition.
WEEKEND ACTIVITIES
1. Carry out an activity to show that heat is released during decomposition.
REFERENCE TEXTS
Senior Secondary Biology 1 by F.O.C. Ndu et-al

TOPIC: FOOD CHAIN, FOOD WEBS AND TROPHICAL LEVELS
CONTENT:
1. Tropical levels (i) Food chain (ii) Food web (iii) Non cycle nature of chemical energy transfer (iv) Nutrient movement
2. Energy flow (i) Food energy relationship in aquatic and terrestrial environments (ii) Pyramid of energy/numbers (iii) Nature of energy flow.
Sub-Topic 1: TROPHICAL LEVELS
As living and non-living things interact, energy is transferred from one level to the other. The ecosystem actually operates as a movement where all organisms depend on the primary producers, the green plants.
FOOD CHAIN
Food chain is the transfer of food energy from producers (green plants) to a series of organisms in a habitat. In the arrangement of the food chain, the natural rule is that it must start from a producer or an autotroph. Some examples of food chain are below:
1. Grass Grasshopper Lizard Snake.
2. Plankton Tilapia Water snake.
3. Dead wood Termite Frog Hawk.
Note that each level of competition in the food chain is called a trophic level. Looking at example 1, it represents the terrestrial habitat.
TROPHIC LEVEL
Now, what is this trophic level? These are stages at which the energy is found as it moves through the various organisms or levels of transfer in the ecosystem. Hence, trophic level refers to the part of food chain.

FOOD WEB: considering food chain energy pathway, you will observe that it is a single energy pathway. In the actual sense, such simple food chains as shown above rarely exist within a community because consumers rarely depend on only one type of food. Often a particular food item is eaten by more than one consumer. Therefore, a network of interrelated food chains forms what is called a food web.
(DIAGRAM OF FOOD WEB)


NON-CYCLIC NATURE OF CHEMICAL ENERGY TRANSFER
The energy flow in an ecosystem is not cyclic because being an energy pyramid, it moves from the producers at the bottom of the pyramid up to a point where it cannot be used by living things anymore. It is either used by the organisms in the ecosystem or it is lost to the atmosphere. For example, energy stored in cow = energy stored in grass – (energy for cow’s activities + energy lost to the atmosphere).
NUTRIENT MOVEMENT
Nutrient movement refers to the chemical energy in form of carbohydrates, fats, protein, and other nutrients are distributed among producers, consumers and decomposers. It just about how nutrients flow from one energy level to the other in the ecosystem.
ENERGY FLOW
Under this topic, we shall consider the following: Food pyramid, Pyramid of Numbers, Pyramid of biomass, and Pyramid of Energy. In any natural community, the number of individuals at the lower part of the food chain or web is greater than those above. Producers are therefore greater than primary consumers, and secondary consumers less in number than the primary consumers. This number reduces till the terminal group of organism is reached which have no predators depending on them for food. When these numbers are diagrammatically represented, a pyramid of numbers is obtained.
Food Pyramid
Food pyramid is a representation of food chain in the food producers from the base and carnivores from the apex.

Pyramid Of Numbers: This is the progressive drop in the population at each higher or successive trophic level of the food chain or the relative decrease in number or organisms in a food chain as one ascends the higher trophic levels.
Pyramid Of Biomass: The pyramid of Biomass (or standing crop) indicates, by weight, the total mass of individuals or organisms at each trophic levels.

Pyramid Of Energy: This is the progressive drop or decrease in the total available energy at each higher trophic level or the progressive diminution of energy in the feeding chain as one ascends the higher trophic levels.
Differences btw pyramid of numbers and pyramid of energy
Pyramid of Numbers Pyramid of Energy
Size of organism is not recognized, only numbers are counted This is based on a common unit of energy joule
Shape is not constant, it might be inverted e.g. grasshoppers feeding on a large tree. Shape is constant


EVALUATION
1. Explain the following with a typical example: Food Chain, Food Web, and trophic level.
2. Why is the energy flow in the ecosystem not cyclic.
3. What is nutrient movement?
4. Write a short note on energy flow.
5. State two the differences between pyramid of numbers and the pyramid of energy.

GENERAL EVALUATION
1. In aquatic habitat, one of these is a primary producer (a) plankton (b) grass (c) tilapia (d) shark (e) Amoeba
2. Which of the following organisms feed directly on green plants? (a)decomposer (b) secondary consumer (c) producer (d) primary consumer (e) tertiary consumer.
3. Trophic levels refers to the part of (a) biosphere (b) hydrosphere (c) a habitat (d) a food web (e) a food chain.
ESSAY TEST
1a. Define the term (i) consumers (ii) producers.
b. Classify the following organisms: cow, bacteria, green plants, herbivores, fungi, and man into producer, primary, secondary and tertiary consumer.
WEEKEND ASSIGNMENT
Sketch the diagrams of the pyramid of numbers, pyramid of biomass in a grassland, and pyramid of energy.
PRE- READING ASSIGNMENT
Read Exam Focus Biology for WASSCE and SSEC by E. Egunyomi et-al (pages 107- 109), and write out your observations in the pyramid of numbers.
WEEKEND ACTIVITIES
Go to the field and observe organisms, and form a food chain of your choice.
REFERENCE TEXTS
Concise Biology for Senior Secondary Schools, by B. N. OKORO.
Exam Focus Biology for WASSCE and SSEC by E. Egunyomi et-al

TOPIC: ENERGY TRANSFORMATION IN NATURE
CONTENT:
1. Energy Loss in the Ecosystem (i) Solar radiation (ii) Energy Loss in the Biosphere (iii) Measure of primary production e.g. the amount and rate of energy fixation
2. Laws of thermodynamics.
Sub-Topic 1: ENERGY LOSS IN THE ECOSYSTEM
You remember that energy exists in various forms, and various forms are interconvertible and as such one form of energy can be transformed into one another form. In nature, energy transformations are brought about by living organisms. Their activities cause energy to flow through ecosystems unidirectionally. Now, how does energy get lost in the ecosystem?
Solar Energy: Only about 2% of solar energy is used by green plants while the rest is lost to the earth’s surface. Thus, energy is a limited factor in the production of autotrophs.
Energy Transformation in Nature
When primary consumer, the herbivores feed on the producers, the green plants, the secondary consumers, the carnivores in turn feed on the herbivores; the energy transferring efficiency in each stage is about 5-20% while the rest is lost to the atmosphere.
Energy Laws: Energy transformations in nature are governed by the laws of thermodynamics.
The first law of thermodynamics states that when one form of energy is converted into another, the total quantity of energy is constant (there is no net loss or gain in energy) that is to say that energy is neither created nor destroyed. Hence, in the process of burning, chemical energy of wood changes into heat and light. In a motor vehicle, energy in form of fuel changes into mechanical energy. So, energy can only be converted from one form to the other.
Second Law Of Thermodynamics: The law states that when one form of energy is converted into another, a proportion of it is converted into heat. The second law of thermodynamics is sometimes known as the entropy law; entropy being a measure of disorder in terms of unavailable energy in a closed thermodynamic system.

How the Laws are Used to Explain Energy Flow across the Trophic Level

Pyramid of energy
1. According to the first law, energy is transferred into a variety of other forms in the successive trophic level but the sum total is constant.
2. Using the second law, we observe that during energy transformation in the successive trophic levels, a proportion of it is converted into heat which is lost, hence the progressive drop in energy in successive trophic levels and also the pyramidal shape of feeding relationship.
Food Chain
1. In accordance with first law, chemical energy stored in plants, can be converted into light energy in glow- worm which in turn is converted into electrical energy in fire-fly and when eaten by man, it is converted into mechanical energy in muscular contraction without any loss or gain.
2. The second law shows that when energy flows through a food chain, only a small proportion of the energy taken up by each link is transferred to the next step. This is because at each transfer, most of the energy is lost as heat.


Heat Loss from a House
A thermograph shows the large amount of heat lost through a house’s windows during winter. Replacing conventional windows with double- or triple-paned windows cuts down the amount of heat that can escape from the house; this conserves energy and reduces heating bills.
Energy Flow
According to the second law:
1. In the flow of energy from herbivore to carnivore, there is loss of usable energy. This loss of energy means that les life can be maintained at highest trophic level.
2. The energy travels from one organism to another with a loss of energy each time it enters another organism. The various organisms represent trophic levels or stages of energy flow.
EVALUATION
1. State the laws of thermodynamics
2. Explain the term entropy law.
3. How does law of thermodynamics apply to pyramid of energy?


GENERAL EVALUATION
1. The first law of thermodynamics states that (a) energy is gained but not lost (b) there is no net gain or loss of energy (c) energy is converted only once (d) the conversion of energy is specific and non directional (e) energy is loss through enthalpy.
2. Only about ---percent of solar energy is used by green plants (a) 10% (b) 20% (c) 2% (d) 5% (e) 80%

ESSAY QUESTIONS
1. Use the laws of thermodynamics to explain food chain.
2. How does the second law apply to energy flow.
WEEKEND ASSIGNMENT
1. Explain what happens when heat is lost in a food chain.
PRE- READING ASSIGNMENT
Read Exam Focus Biology for WASSCE and SSEC by E. Egunyomi et-al (page 109), and use the second law to explain the energy flow across the trophic level.
WEEKEND ACTIVITIES
Explain various ways through which energy flow from the producer to you.
REFERENCE TEXTS
Concise Biology for Senior Secondary Schools, by B. N. OKORO.
Exam Focus Biology for WASSCE and SSEC by E. Egunyomi et-al
Lamlad’s SSCE &UTME Biology by G. A. O. ARAWOMO.

TOPIC: RELEVANCE OF BIOLOGY TO AGRICULTURE
CONTENT:
1. Classification of Plants
- Botanical classification
- Agricultural classification
- Classification based of life cycle
2. Effects of Agricultural Activities on Ecological system
3. Pests and Diseases of Agricultural importance

SUB-TOPIC 1: CLASSIFICATION OF PLANTS
Classification of plants is based on botanical techniques and agricultural techniques. The botanical techniques where all plants are grouped into plant kingdom based mainly on structure, function and evolutionary trends is not very useful to a farmer. The agricultural techniques involve nature of the products and life cycle. Hence plant can be classified based on the following:
4. Botanical classification
5. Nature and uses of products
6. Life cycle
BOTANICAL CLASSIFICATION
This is the classification system of flora and fauna that uses the binomial system of nomenclature in which every plant is given two names (generic and specific names). The generic names are always written first starting with capital letter while the Last which is the specific names are written in small letters. The names are either italised or underlined separately. E.g. Rhizopus nigricans or Marchantia Palmata.
Based on what is present or absent on the plants, Botanis grouped plants by considering the plants structure, presence of flower and mode of reproduction. Plants are classified into two groups (i) non flowering plant (ii) flowering plants

(a) Non-flowering plants
These are plants that do not have or produce flower. They are lower plants lacking vascular bundles, they lack true roots stems and leaves. The non-flowering or seeedless plants are classified into three groups:
• Thallophyta: these are plants that have bodies called thalli. They lack organs like roots, stems, leaves, flowers and fascular tissues. Examples: Algae, fungi, bacteria and Lichens.
• Bryophyta: the plants are multicellular and non vascular. They have stemlike and leaf-like structures but lack roots. Bryophytes live in moist place and reproduce by spores. They have rhizoids through which the plant absorbs nutrients from the soil.
• Pteridophyta: they are multicellular plants with true roots, stems and leaves but lack flowers. The vascular system os primitive as well as chlorophyll. They reproduce by spores. Some of them are acquatic while some are terrestrial e.g. ferns (Dryopteris, Nephrolepsis).

(B) Flowering plants:
These are the higher plants called spermatophytes or seed plants. They produce flowers and are vascular plants. Spermatophytes are further grouped and classified into angiosperms and gymnosperms.
(i) Angiosperms: these are plants produce seed which are enclosed. Seed is produced and protected by seed coat. Angiosperms are further grouped into dicotyledons and monocotyledons.
 Dicotyledons are plants with two seed leaves or cotyledons. The leaves are net-veined or reticulate e.g. beans, melon, mango and tomato.
 Monocotyledons are plants with one seedleaf or one cotyledon. They have parallel-veined leaves. They possess fibrons root systems.
(ii) Gymnosperms: this group also produce see but the seeds are naked. The seeds are not enclosed in the plant e.g. pines and cones.
AGRICULTURAL CLASSIFICATION
In agriculture, cultivated plants or crops are grouped according to the products for which they are grown as given below:
 Cereals: these plants belong to the grass family. The grains have a high starch content and varying amounts of proteins e.g. maize, rice, millet, wheat and guinea corn.
 Legumes: these plants are important source of dietary protein. They also supply protein-rich fodder for livestock in tropical countries. Legumes replenish soil nitrogen-fixing bacteria are present in their root nodules. Examples include beans, cowpea, soya-bean, groundnut, oil bean, lina bean and yam-bean.
 Root crops: they are grown mainly for starch and form the staple food of the people in many tropical countries; e.g. cassava, yam and sweet potato.
 Vegetables: they are grown to supply dietary vitamins and certain minerals like calcium. Examples include tomato, okra, onion, pepper and spinach.
 Fruits: fruits are rich sources of vitamins especially vitamins A and C, minerals and sugars. Most fruits are eaten raw. Examples include orange, banana, pineapple, plantain, mango and pawpaw.
 Beverages and drugs: the crops which yield these product include cocoa, coffee, tobacco and guinea.
 Spices: pepper, ginger, cinnamon and cloves belong to this group. They are used mainly for flavouring food.
 Oils: oils producing plants include coconut, oil palm, shea-butter and groundnut.
 Latex: when a cut is made on the trunks of certain trees, a milky fluid called latex flows out. The rubber tree produces white latex which is coagulated into exported rubber.
 Fibres: Plants such as jute, hemp and button are grown for their fibres which are used for making ropes and cloth.
Forage crops: these are grasses and legumes that are grown for animal feed.

Agriculture in the Qatar Desert
On a government-supported farm in Qatar, seedlings sprout from carefully monitored containers. Only about 3 percent of the land in this largely arid country is under cultivation. Technology has improved crop output significantly, however, and during the rainy season, Qatar now produces nearly all the vegetables it needs for a six-month period.



CLASSIFICATION BASED ON LIFE CYCLES
Plants are grouped on how long or short they live to complete their life cycle i.e. duration of their life cycles. It is a practical way of classifying crop plants as it helps a farmer to plan how to use his land to meet his goals. Plants are classified into animals, biennials and perennials.
7. Annuals: these are plants that complete their entire life cycle and die within one growing season which may be from a few month to a year. Examples includes rice, wheat, maize, beans, flax, jute and sunflower.
8. Biennials: these are plants which complete their life cycled in two years. The plant grow and store food during the first growing season to produce and use it in the second growing season to produce flowers fruits and seed before they die. Examples include cabbage, turnip and radish.
9. Perennials: these plants complete their life cycles in many years or have many growing seasons for life cycles to be completed e.g. mango, orange, oil palm, and ginger.
EVALUATION
• State two differences between angiosperms and gymnosperms.
• State two differences between monocotyledonous and dicotyledonous plants.
• Give two examples of each of the following groups of plants. (a) cereals (b) fibres (c) legumes (d) beverages (e) oils.
• Classify plants on the bases of life cycle.
SUB TOPIC 2: EFFECTS OF AGRICULTURAL ACTIVITIES ON ECOLOGICAL SYSTEMS.
Agricultural activities involves both growing of crops as well as rearing of farm animals. Ecological system refers to the interrelationship between living organisms and their environments. The natural dynamic balance between plant and animal communities in the ecosystem is often disturbed by agricultural activities such as burning and tillage. Bush burning

Roadside Market in Bulgaria
People buy red peppers and other vegetables at a farmers’ market in a suburb of Sofia, the capital of Bulgaria. Although privatization of Bulgaria’s economy has been slow, most farmland once controlled by the state is now owned by independent farmers.

In many places, some areas used for cropping is always set on fire before the cropping season. The ash produced by the burnt rubbish increases the alkaline content of the soil. This replaces the acidity of the soil in most tropical African soil. In contrast, burning exposes the soil surface to erosion by wind and rain, reduces the humus content of soil, destroys micro-organisms of the soil, kills small animals such as insects and earthworms, and destroys other important plants and animals. As a result, the balance of the ecosystem is disturbed by bush burning.
Pesticides
The use of pesticides in some cases disturbs the dynamic balance of the ecosystem in some unexpected ways. Insecticides affect both beneficial and harmful insects. DDT is a very stable compound; instead of being excreted by animals, it is stored in their body fats when such fat is oxidized during respiration in some animals, harmful quantities of DDT may be librated into the blood.
Effects of different types of farming have effects both desirable and undesirable on ecological systems.
Different kinds of farming have effects both desirable and undesirable on ecological systems. These effects are explained below.
(a) Shifting cultivation: the method is possible where population is small and where land is abundant. Ecologically, large population with small land results in overuse which inturn leads to total loss of soil fertility.
(b) Crop rotation: crops grown are rotated in success seasons. The method gives better yield for respective crops because different crop make different demand of mineral elements of the soil.
(c) Mixed farming: this involves keeping livestock and growing plants side by side. As the product of crops isbeing used as food to feed livestock, the remains (faeces) of the livestock can also be used as manure for the farm crops.
EVALUATION
• List three agricultural activities that disturb ecological system.
• State four effects of bush burning on ecological system.
• Name three farming methods and explaining how one of them affects the ecological system.
SUB-TOPIC 3: PESTS AND DISEASES OF AGRICULTURAL IMPORTANCE
Pests are insects or animals which cause damage to farm, animals, plants, food and crop. Some pests attack crops and animals in the farm. A disease is a departure from normal state of health, expressing remarkable symptoms or outward visible signs. Both pests and diseases reduce the quality and quantity of crop and animal yield or even kill them.

PLANT AND PESTS
The most devastating pests of crops are insects e.g. grasshoppers, locusts and caterpillars. Other plant, pest includes nematodes, rodents and birds. Insects and rodents always destroy stored crops like cocoa, coffee, groundnuts and yam. Pests cause plant diseases. Specific plant pests include the following:
 Caspid bugs of cocoa: they feed on leaves, stems and pods. The pest is more prevalent in dry season. Caspids are controlled by spraying with Aldrex 40, BHC, Dieldrin and Gamalin 20.
 Cotton stainer bugs are common in cotton growing are. They are tiny, red-coloured insects which pierce the young bolls and seeds in the open bolls and suck the sap. These insects transmit viral, fungal and bacterial diseases from one plant to another. The fungus causes the boll to rot internally and stain the ling.
 Yam beetles can destroy a whole yam crop plantain within a year. The pests are controlled in Nigeria by treating yam setts and seeds with Aldrin just before planting. Other pests of yam are eel-worm which feed on tuber rodents and wild animals which destroy the tubers.
 Pests of cassava are grasshoppers that feed on the leaves and young shoots, some rodents that feed on cassava tubers and stems and untethered goats and sheep can eat up all the leaves and stems of cassava.

Control of plant pests
Pest control is aimed at protecting crops from damage and getting rid of the pest population. Control measure of plant pest can b applied through the following methods:
- Physical method e.g. handpicking of pests and deterrents such as bird scares on small farm area with low infestation.
- Cultural method: modifying farm practices to discourage pest multiplication.
- Chemical method i.e. use of pesticides.
- Biological method e.g. introduction of predators.
- Sterilising male technique.


Natural Pest Control
Ladybird beetles, or ladybugs, have had their name since the Middle Ages, when people looked upon them as a gift from the Virgin Mary because of their miraculous eating habits. As both larvae and adults, ladybugs feed on aphids and other agricultural pests. Many gardeners buy ladybugs at garden stores and release them in their gardens to stave off aphids


PESTS OF ANIMALS
Animals or livestock pests are often parasitic on their victims. Livestock pests are either ectoparasites or endoparasites.
 Ectoparasites: some of them are vectors of diseases e.g. ticks vectors of tick fever and heart water disease of cattle, sheep and goats. Other ectparasites of livestock are lice, nites, fleas and flies.
 Endoparasites: these include flat worm (e.g. tapeworm and liver fluke) or round worm (e.g. Ascaris, Hookworms) or protozoa e.g. Trypanosome and coccidian which cause coccidiosis. Endoparasites injure the tissue or organs in which they live. They cause wasting, stunting and death of livestock when they occur in large numbers.
Control of Endoparasites
Two ain effective ways of controlling endoparasites are:
o The use of appropriate drugs as diredted by the veterinary department.
o Proper management to ensure that domestic livestock does not come in contact with the parasitic eggs or larvae.

SOME DISEASES OF PLANTS
Diseases of plants are commonly caused by fungi, bacteria and virus. The table below

Table Summary of the causes, symptoms and control.
DISEASE CAUSATIVE
ORGANISM HOST MAJOR SYMPTOMS CONTROL MEASURES

Anthracnose Fungi Cocoa, coffee, cotton and oil palm Brown, water soaked patches on leaves and pods Use of fungicides
Black pod Fungi cocoa Dark brown, or black rot on pod, damage to fruit and seed walls Spraying with fungicides, farm sanitation
Brown spot Fungi Maize Purplish-brown spots on leaves. Entire plant may break up. Avoid planting on infected spots
Bacterial wilt Bacteria Banana, plantain, cassava, tobacco and groundnut Leaf wild and defoliating. Wilt of entire plant Use of clean planting material, good sanitation
Mosaic Virus Cassava and tobacco Leaf-mottling with dark green and greenish yellow patterns Use of resistant varieties

SOME DISEASES OF ANIMAL
The common diseases which affect domestic animals could be grouped as follows:
• Bacterial diseases e.g. black quater, anthrax, foot rot, fowl pox, tuberculosis and contagious abortion.
• Fungi disease e.g. ringworm
• Nutritional disease e.g. rickets, milk fever, ketosis, bloat and osteoporosis.
• Protozoan diseases e.g. coccidiosis, tick fever and trypanosomiasis (sleeping sickness)
• Viral diseases e.g. foot and mouth diseases, foul cholera, Newcastle disease, pleuropheumonia, rinderpest and typhoid fever.
Selected Domestic Animal disease
DISEASE CAUSATIVE ORGANISM HOST MAJOR SYMPTOMS CONTROL MEASURES
Coccidiosis Proto zoan Cattle, foul, sheep, and goat Bloody diarrhoea, weakness, emanciation and death Good sanitation. Avoid overcrowding. Disinfected sulphamethazine.
Anthrax Bacteria Cattle, goat, pig and sheep Premature birth, still-birth, retention of afterbirth and sterility Vaccination of young animals before age of breeding. Good sanitation.
Newcastle Virus Poultry Yellowish droppings, comb turns purple. Coughing, gasping and death No effective cure. Kill off infected bird. Disinfected pens. Consult a veterinary officer
Ringworm Fungus Cattle and horses Lesions at the base of hairs. Hairs fall off and itching Use fungicides to wash lesions. Use antibiotics as oral treatment
Rabies Virus Cats, cattle , dogs, horses, sheep and pigs Excitement, tendency to attack, paralysis in coordination and death No effective treatment. Control by vaccination and avoiding exposure to infection.


EVALUATION
1. State three general effects of pest and diseases on crops and animal.
2. Name two plant pest and how they can be effectively controlled.
3. State two main effective ways controlling endoparasites of livestock.
4. Use a table to describe the causative organism, the host, the major symptoms and control measures of the following diseases:
(a) Mosaic (b) black pod (c) coccidiosis (d) ringworm.

GENERAL EVALUATION
Objective Questions
1. The following are examples of cereals except (a) maize (b) rice (c) millet (d) bean
2. Which of the following does not belong to the major four divisions of plant kingdom (a) thallophyta (b) tracheophyta (c) pteridophyta (d) bryophyte
3. Which of the following pest control method involves the use of pest enemies? (a) cultural method (b) biological method (c) physical method (d) chemical method
4. Which of the following is affected by black pod diseases? (a) oil palm (b) cocoa (c) rubber (d) cowpea
5. Which of the following diseases is caused by a virus? (a) mosaic (b) brown spot (c) black pod (d) anthracnose
ESSAY QUESTIONS
1. (a) List any four main divisions of the plant kingdom.
(b) List any ten classifications of plants based on the nature and uses of their products, giving two examples in each group.
2. (a) In a tabular form state any five differences between monocotyledons and dicotyledons.
(b) Discuss any five agricultural practices that have harmful and beneficial effects on these plants stating their effects on these plants and how they can be controlled.
3. Mention any four pests of named plants and how they can be controlled.
4. (a) List any five groups of animal diseases and give one example each.
(b)Briefly discuss the effects of bush burning on a piece of farm land.
5. (a) State four ways of controlling plant pests and discuss any two of them.
(b) Use a table to explain the causative organism, host, major symptoms and control measures of the following diseases (i) coccidiosis (ii) Newcastle (iii) anthracnose (iv) brown spot.

WEEKEND ASSIGNMENT
Read Modern Biology for Senior Secondary School by Sarojini T.R. (4th edition reprinted 2010) page 62 – 77

PRE-READING ASSIGNMENT:
Read about Food Production and Storage.

WEEKEND ACTIVITIES: List five environmental factors that the production of crops and identify any ways by which farm crops are wasted.

REFERENCE TEXTS:
1. Nelson Functional Biology for Senior Secondary Schools by Kola Soyibo et al. Pages 152 – 164.
2. Modern Biology for Senior Secondary Schools by Sarojini T.R. (4th edition reprinted 2010) pages 62- 77.
3. Melrose Biology for Senior Secondary Schools. Bk 1 by Obayori O.S. page 103-107.

RELEVANCE OF BIOLOGY TO AGRICULTURE

CONTENT:
1. Food production and storage
(a) Ways of improving crop yield
(b) Causes of wastage
(c) Methods of persevering and storing food.
2. Population growth and food supply
3. Relationship between availability of food and human population (effects of storage).
4. Government efforts to increase food production (e.) agricultural revolution.

SUB-TOPIC 1: FOOD PRODUCTION AND STORAGE
The primary aim of agriculture is to provide adequate food for an ever increasing human population. The issue of food production, preservation, storage and wastage has been challenging to both the agriculturist and the government.

Adequate food production makes food available for teaming population to be well fed. It also earns the country foreign exchange through exportation of food crops. One the other hand, food shortage will increase death rate and cause migration of people to where food is available. There will be competition among organism which in turn leads to starvation and cannibalism. Natality or birth rate will be affected through avoidance of marriage.
(a) WAYS OF IMPROVING CROP YIELD
Crop yield can be improved through the following ways.
(i) Breeding high yielding crops that are resistant to plant and animal disease.
(ii) Using fertilizers and organic manure to maintain soil structure and fertility and ensure high crop yield.
(iii) Using effective method of farming such as irrigation, tillage and draining systems.
(iv) Combating weeds by using herbicides instead of cutlasses and hoes.
(v) Plant protection from pests and disease to improve yield.
(vi) Putting more land under use by motivating and formulation policies that will get more people to be involved in farming.
(vii) Practicing mechanised farming to obtain high yield. Tractors and modern farm implement to be adopted instead of manual farming.
(viii) Conservation of land to keep and maintain soil fertility. Soil erosion should be prevented, bush burning should be avoided while mulching and crop rotation should be encouraged.
(ix) Use of correct agricultural practices such as removing weeds regularly, giving adequate spacing and planting at the right time will improve crop yield.
(b) CAUSES OF WASTAGE
Reasons why crops are wasted annually on farms include the following:
1. Late harvesting of crops: some crops are over ripe, rot and fall off due to lateness in harvesting.
2. Bad harvesting techniques and incomplete harvesting. Harvest should be invested on and used. Man may skip maize harvest and such maize may be wasted.
3. Delay in transporting crops which make some drops to rot.
4. Lack of good storage facilities; good barns and storage facilities should be made available. If harvested crops are not properly stored wastage will occur.
5. Infections of farm produce by fungi, insects and vermin due to inefficient storage method.
6. The decay of some stored crops caused moisture, especially when they are not properly stored e.g. groundnut, maize and rice.
7. Lack of good roads and good means of transportation for carrying farm to the market or urban centres.
8. Poor method of preservation of some farm produce like tomatoes, carrots, vegetable and other perishable crops.
METHODS OF PRESERVING AND STORING FOOD
The methods commonly used in preservation and storage of foods include the following:
1. Drying: food items such as meat and fish can be dried to preserve food and prevent damage. Drying remove water from food and prevent growth of organism that can cause decay.
2. Salting: common salt is added to fish and meat. Salt kills the bacteria by high osmosis pressure.
3. Refrigerating/ freezing: keeping food at low temperature prevents bacteria growth. Meat, fish and vegetables are preserves in this way.
4. Smoking: this removes water from food and prevents growth of microbes on food. Microbes are killed by poisonous substances such as phenols, present in the smoke.
5. Canning: if the food is sealed and air excluded, growth of micro organisms will be impossible. High temperature kills the microbes and kills the microbes and keeps the food.
6. Chemicals: the application of preservatives and protective chemicals on the food keep pests away and also prevents bacteria and fungi from growing on the food, thereby preventing decay.
7. Pasteurisation: it is special method of preserving milk. Milk is pasteurised by heating to 72% for 15 seconds and then cooled rapidly. This destroys micro organisms, thereby preventing the milk from becoming sour very quickly.
Other methods of food preservation are fermentation and radiation.


Pest Control or Pollution?
Pest control has become a difficult issue for farmers because of its potential environmental impact. Although the insecticide being sprayed on this potato field will eliminate a generation of Colorado potato beetles, it may also contaminate local food and water sources.

EVALUATION
• List three dangers of inadequate food supply to the population.
• State four ways of improving crop yield.
• State five causes of crop wastage
• List seven method of food preservation

SUB-TOPIC 2: POPULATION GROWTH AND FOOD SUPPLY
Population can be defined as the total number of organism of the same species living in a habitat over a period of time. Food supply affects population growth both positively and negatively, based on availability or unavailability of food in a habitat.
If food is adequately available organism will be well fed, give birth to new ones; death rate reduces and population rises. When there is inadequate supply of food, the organism is malnourished, there is competition for the limited food, birth rate reduces, death rate increases and there is a decline in population of the organism. The number of organism migrating out of the habitat increases and cannibalism may set in.
Factors affecting population growth include the following:
- Reproduction (birth rate)
- Migration (movement of organism)
- Death (death rate)

Experiment to demonstrate effect of food on population
Aim: to show the effect of food on mice population.
Method: some mice or rodents are kept it two cages. Those in cage 1 are provided with a lot of food and water at the beginning of the experiment. Those in the second cage are supplied with enough food and water continually. The mice left for some time.
Observation: the number of mice continues to increase in the cage with food continuous supplies of food. The population of mice in the cage with food supplied only once will increase for a while when there is no food most of them start to die.
Conclusion: the population of mice tends to increase when there is plenty of food, while their population tends to decrease when there is no food.

EVALUATION
 Define population.
 State three factors that influence population of an habitat
 List three effects of inadequate food supply on population
 Describe an experiment that shows the effect of food supply on population.

SUB-TOPIC 3: RELATIONSHIP BETWEEN AVALABLE FOOD AND HUMAN POPULATION
Malthusian hypothesis that human population increases by geometric progression while food increases in arithmetic progression, is an indication that relationship exists between population and food supply. At a point therefore, population will outgrow the supply of food and population growth will stop at one point. Malnutrition, hunger and possibly death will follow to reduce the population to the level the food can cater for.


Starving Children in Niger
Due to climate, drought, poor agricultural planning, political instability, war, and the mismanagement of natural resources, there were about 820 million undernourished people in the developing world in 2006. Only a small percentage of hunger deaths are caused by starvation. Most hunger-related deaths are the result of chronic malnutrition, which weakens the body's ability to fight diseases. In 2003, almost 16,000 children were dying from hunger-related causes each day.

EFFECTS OF FOOD STORAGE
Naturally, some crops are meant to grow in wet season while some few are grown in the dry season. If there is no good storage facilities, distribution of food across the season will be difficult; as there would be a period of plenty of food and another period of food shortage. To strike a balance, storage facilities will make equitable distribution of food and food will be available in required quantities at all seasons. Advantages of food storage include the following:
1. Provision of employment opportunities i.e. to workers in processing industries.
2. Provision of adequate food supply during period of war and natural disaster.
3. Stabilisation of food prices at all season. Equitable distribution of food will prevent unnecessary high demand for food at any time which may lead to like in prices of food.
4. It ensures economic use of food by preventing spoilage at time of plenty and adequate supply of food at off-harvest period.
5. Provision of foreign exchange to improve the economy of the nation. Food can be used as aids to countries in need as love and donations.
EVALUATION
1. Name five crops that are produced during the wet season but are scarce during the dry season.
2. State two needs for food storage.
3. State four importance of food storage.

Agriculture in Iraq
Agriculture, an important part of the Iraqi economy, became even more essential after the United Nations (UN) imposed trade sanctions on the country in 1990, following Iraq’s invasion of Kuwait. Iraqi farmers grow grains, dates, grapes, figs, and other crops, while nomadic and seminomadic Iraqi herders raise livestock. Yet before the UN trade embargo, Iraq had imported approximately 70 percent of its food. This photograph shows an Iraqi farmer bagging grain.

SUB-TOPIC 4: GOVERNMENT EFFORTS TO INCREASE FOOD PRODUCTION
Many African countries has embarked on gigantic agricultural development programmes that failed
Because of undefined government policies, absence of planning, lack of skilled and experienced personnel and inadequate provision of funds by the government.

In Nigeria, huge finance invested in various governments’ agricultural programmes (such as Operation Feed the Nation and Green Revolution) was grossly mismanaged. Gross financial management has also crippled many of the River Basin Authorities established by the Federal Government to boost agricultural production.

Factors that adversely affect food production include:
• Unfavourable climatic conditions e.g. drought;
• Lack of improved varieties of plant and livestock.
• Conservative attitude of local farmers
• Inability of many farmers to use modern farming techniques and;
• Outbreaks of insect pest and diseases.
Government should do the following to aid crop production
1. Provision of irrigation system to supply water for planting at all season.
2. Provision of modern farming equipment to replace manual clearing equipment used by farmer.
3. Provision of good roads and other infrastructure that can aid food production, movement and storage.
4. Fertilizer should be made available at reasonable cost to farmers to improve soil fertility and boost crop production.
5. Training of local farmers in modern day farming to improve their skills.
EVALUATION:
 List three agricultural programme established by the government to boast food production.
 State three factors that hinders food production.
 State four ways by which the government can improve food in Nigeria.

GENERAL EVALUATION
OBJECTIVE TEST
1. Which of the following factors does not affect population growth? (a) food supply (b) games and sport (c) reproduction (d) migration
2. Food can be preserve through all except (a) fermentation (b) washing (c) pasteurisation (d) radiation.
3. Which of the following does not cause food wastage? (a) storage (b) pest (c) diseases (d) delayed harvesting
4. Which of the following is not an outcome of inadequate food supply to a population(a) migration (b)competition (c) population growth (d) cannibalism
5. Which of the following factors does not have adverse effect on food production? (a) unfavourable climate condition (b) outbreak of pest and diseases (c) irrigation system (d) good road network

ESSAY QUESTIONS
1. (a) List ten method of food preservation.
(b)Discuss any two methods of food preservation.
2. (a) State any five environmental factors that affect crop production.
(c) State any five ways by which farm crops are wasted.
3. (a) list three major consequences of food shortage in the world growing population.
(a) Describe an experiment to show the effects of food supply on population
4. (a) State five causes of crop wastage.
(c) State four ways of improving crop yield and discuss any one of them.
5. (a) Name three agricultural programmes aimed at increasing food production.
a. State five ways by which government can improve food production in Nigeria.

TOPIC: MICRO ORGANISM AROUND US
CONTENT:
1. Micro organism in air and water.
(i) Group of micro organisms: bacteria, viruses, some algae, protozoa, fungi.
(ii) Concept of cultivating
2. Identification of micro-organism in (i) Air (ii) pond water (iii) river (iv) concept of cultivating
3. Micro-organisms in our bodies and food.
4. Carriers of micro organisms – examples, location of the micro-organism in carriers and types
of micro organism.

SUB-TOPIC 1: MICRO ORGANISMS IN AIR AND WATER.
Introduction: Micro organisms are very tiny living organisms are also known as microbes.


T-Lymphocyte Infected With HIV
Human immunodeficiency virus (HIV) is the cause of acquired immunodeficiency syndrome (AIDS). By infecting CD4 T-lymphocytes, a type of white blood cell, HIV weakens the immune system and leaves the infected individual open to deadly infections. The viruses gain access to a T-lymphocyte by attaching to CD4 proteins on the outer surface of the cell membrane.

MICROBES
Anthony Van Leeuwenhock (1632 – 1733) was the first scientist to discover microbes with his newly invented microscope.
Micro-organisms are dreaded as disease causing agents (germs). However, many microbes are of great benefits to man e.g. saprophytic microbes that bring about decay of organic matter. Those microbes that affect man negatively are mainly the parasitic ones which are called pathogem.
Micro organism are found everywhere- in the air, water, siol, in our own food, on our food on surfaces of object, and on inside living organisms, on our bodies, inside of our bodies and on our clothes in shut, anywhere everywhere.

1. Groups of micro organisms:
Microbes are very many and are grouped as follows:
(a) Bacteria
(b) Viruses
(c) Some algae
(d) Protozoa
(e) Some fungi
Most microbes are unicellular but some fungi and algae are multi-cellular. Several microbes survive adverse conditions of temperature or humidity by forming spaces the within the cell. On the return of favourable condition of the spores are released carried in the air and on landing on suitable substrate grow and produce more spores.


Hepatitis B Virus
The hepatitis B virus (HBV) causes inflammation of the liver. The virus is recognizable under magnification by the round, infectious “Dane particles” accompanied by tube-shaped, empty viral envelopes. Symptoms of hepatitis B infection include jaundice and a flulike illness, while chronic infection can lead to serious problems such as cirrhosis and cancer of the liver.

BACTERIA
Bacteria can be seeing with the use of light microscope. It has a simple structure. It is unicellular. It is a prokaryotic cell i.e it does not have a true nucleus. Heredity materials are contained in a strand of DNA (Deoxyribose nucleic acid) inside the cell.
Diagram of a Bacterium STAN BIOLOGY Pg 216
Bacteria can be described to be aerobic, anaerobic on facultative .
i. Aerobic Bacteria: This group of Bacteria uses oxygen in respiration e.g. vicbrio choleria.
ii. Anaerobic Bacteria: This group of bacteria do not utilize oxygen in respiration e.g. putrifying bacteria.
iii. Aquacultive Bacteria: These are bacteria that live in the two states above i.e. they can use oxygen and they can also do without oxygen (aerobic and anaerobic).
Drawings Modern Biology Pg 170
On the bases of shape, bacteria are grouped as follows.
i. Cocci:- This group are round in shape.
ii. Bacilli:- They have rod-like shape.
iii. Spirillae:- These are spiral in shape.
iv. Vibrious:- They are comma shaped.
v. Flagellate:- A number of bacteria have whip-like structure called flagella that effect their movement.
Bacteria do can be a number of plant and animal diseases. Plant diseases caused by bacteria e.g. web blight in cowpeas, black arm in cotton etc.
Animal diseases caused by bacteria- leprosy, lockjaw, cholera etc.

b. Virus: they are unicellular without nucleus, cytoplasm and cell membrane. Smaller than bacteria and can only be seen under electron microscope. Virus lack life. Thus it cannot respire nor carry out metabolism. They can only survive inside living cells.
c. Algae: they are mainly free-living microscopic plants. They survive in a wide range of habits such as wet soil, fresh water, sea etc. they have chlorophyll to a number of other pigments giving rise to green algae, brown algae, blue/green algae etc. examples of algae are: Spriogyra, volvex, chlamy domanas, Ulothux, Diatons etc.
d. Protozoa: These are unicellular microscopic animals. They are found in damp soil and water. Some of them are parasitic while others live freely in their habit. Examples of parasitic protozoa are: Trypanosome, plasmodium etc. examples of free-living Protozoa are: Amoeba, Paramecium etc. parasitic Pprotozoans are pathogens that cause disease like Malaria, sleeping sickness, Bilharziasis etc.
e. Fungi: These are non-green simple plants. They feed Saprophytically or parasitically. Saprophytic fungi such as mucor, yeast, penicilium are useful to man. Parasitic fungi do cause diseases which are unpleasant to man. Example of animal diseases caused by fungi is: Ringworm, Athelet’s foot, mouth thrush, candidioses etc. plant diseases caused by parasitic fungi are: mildews, spots, wild, blights and Rots.

Anatomy of a Simple Bacterium
Bacteria cells typically are surrounded by a rigid, protective cell wall. The cell membrane, also called the plasma membrane, regulates passage of materials into and out of the cytoplasm, the semi-fluid that fills the cell. The DNA, located in the nucleoid region, contains the genetic information for the cell. Ribosomes carry out protein synthesis. Many baceteria contain a pilus (plural pili), a structure that extends out of the cell to transfer DNA to another bacterium. The flagellum, found in numerous species, is used for locomotion. Some bacteria contain a plasmid, a small chromososme with extra genes. Others have a capsule, a sticky substance external to the cell wall that protects bacteria from attack by white blood cells. Mesosomes were formerly thought to be structures with unknown functions, but now are know to be artifacts created when cells are prepared for viewing with electron microscopes.

CONCEPT OF CULTURING
Culturing is a technique of growing micro-organisms in the laboratory for the studying the microbes. The process have to do with:
1. Preparing a steule medium
2. Inoculating
3. Incubating
4. Examining micro-organism in the medium.
While bacteria, fungi and algae can be grown in test tubes and Petri dishes in culture media, viruses cannot be grown. They can only grow and multiple inside.
Through Tissue culture, living tissues and cells of multi-cellular organism are cultured in appropriate media and studied. To carry out studies involving viruses, are cultured in the laboratory by injecting the virus into the fertilized Bird egg e.g. egg of duck.
On the culture medium, micro-organisms occur as colonies. Colonies of micro-organism do clump together in large number of organism of the same kind. Colour, appearance other characteristics of the colonies enable the investigator to identify and differentiate microbes in a culture medium.

EVALUATION
1a. What are Micro-organism?
b. List the important groups, giving examples of each group.
2a. Expalin the concept of culturing.
b. What steps will you take in preparing a culture solution and state precautions in preparing it.
c. Identify sources of samples for culturing.

ASSIGNMENT
Read up Identification of Micro-organisms in the Air, Pond water, Rivers and Streams and Micro-organism in our bodies and food.
Read more on concept of culture. Modern Biology Pg 166-170 and (1) outline different types of culture. (2) state importance of tissue culture.

SUB-TOPIC 2: IDENTIFICATION OF MICRO-ORGANISMS IN AIR, POND WATER, RIVER, STREAM
- Micro-organisms in our bodies and food.
- Carries of Micro-organisms, examples, location of the Micro-organisms in carries.
- Types of micro-organisms.
MIRO-ORGANISMS IN THE AIR
Micro-organisms commonly found in the air are: Bacteria, Virus and Fungi. These microbes do not grow in the air but are present as spores in dust and water droplets in the air. These are spores are light and easily dispersed by air movement. When these spores land on suitable substrate, they germinate, multiply and produce more spores. Micor-organisms found in the air and examples:
a. Bacteria: Examples – Pneumacocci, Staphylococci, Sterptococci, Bacillus anthracis which causes anthrax in herbivores.
b. Virus: examples – Influenza, Polio virus, common cold virus, measles virus.
c. Fungi: Examples – Sacromyces (yeast), Rhizopus nigricens (bread mould), Penicillium (blue-green mould) Aspergillus etc.




Bacterial Cultures
Colonies of the bacteria known as Escherichia coli (larger, pink) and Proteus vulgaris (smaller, brown) grow side by side in this petri dish culture. Under normal circumstances both of these bacteria harmlessly inhabit the human intestines and aid in digestion, but can become pathogenic and cause infections, such as urinary tract infections. Scientists and doctors grow cultures of bacteria and study their characteristics in order to learn about bacterial diseases and disease prevention.

Micro organisms in water
Micro organisms found in water are commonly known as plankton. Aquatic environment, unlike atmosphere are rich in organic and inorganic nutrients. They can be found in all types of water habitat viz: wells, ponds, lakes, streams, rivers and seas.
All microbes found in water can be grouped into three as follows:
• Natural water micro-organisms: these are microbes that are naturally found in aquatic habitats.
• Soil micro organism ( washed into the surrounding water bodies during heavy rains)
• Sewage micro-organisms
•

Spirochete
Bacteria, included within the kingdom Prokaryotae, are single-celled organisms lacking a well-defined internal cellular organization. The bacterium Leptospirilla ichterohemorrhagiae, pictured here, exhibits the spirochete, or spiral, structure characteristic of many of the 1600 species of bacteria.




Micro organisms in water and their examples:
1. Bacteria: examples – aquatic species of coccus, Baccillus, Pseudomonas, Azobacter, Thiobacillus, Sarcinina, spirillum, Micrococcus, Vibro and Spirochaeta. These bacteria are either heterotrophic, autotrophic and chemotrophic.
2. Blue – green algae: examples; oscillatoria, nostoc, anabaena,
3. Protists: these are autotrophic diatoms e.g. chlamydomonus, cholleraand some species of euglena as well as heterotrophic amoeba and paramecium.
4. Algae: these are located close to the shore of where they form thick green floating mesh e.g. spirogyra, volvox etc. Algae arte major part of primary producers in the aquatic habitat since they contain chlorophyll and can photosynthesis.

MICRO-ORGANISMS IN OUR BODIES
Various parts of human body such as the skin, hair, mouths, nose, ears, under the nails, our teeth etc to different micro-organisms as well as serve as entrance for these micro-organisms into our bodies.

Millions of micro-organisms living inside and outside the human body. These microbes are non-pathogenic. They are regarded as the normal micro flora which plays importance role in the body.
This normal micro flora prevents pathogen from invading the body as well as secretes certain substances that inhibits or kills some other pathogens. Weakened immune systems , indiscriminate use of antibiotics, unhygienic practices like smoking and intake of alcohol malnutrition, stress etc could make non-pathogen to become pathogenic harmful to the body as the normal micro flora become disturbed.
Pathogens harm the body by using up the hosts’ nutrients thereby starving the tissue of the host.
Through their actions they damage tissues of the affected part of the host as well as produce toxins that negatively affect the functioning of particular organs or body systems of the individual.

Anthrax Bacteria
An electron micrograph shows a cluster of bacteria, Bacillus anthracis, in a capillary of a lung. The bacteria cause anthrax, a disease in humans and animals that can result in death. Anthrax can be cured when treated early with antibiotics.

ENTRY OF MICRO ORGANISMS INTO OUR BODY
Micro-organisms enter the human body through;
 Bucal cavity: the food we eat and the water we drink. Such pathogen cause air borne infection like tuberculosis cause by mycobacterium tuberculosis
 The nose: Air we breathe in, into the respiratory system such virus normally cause cold.
 Damages skin: cuts or bruises on the skin into the blood stream Telamus. fungi infection, leading to ringworm on the head, foot etc.
 Oesophagus: contaminated food or drinking water.
 Direct contact: skin surface e.g. fungal infections which result in ringworm of the head and foot.

MICRO ORGANISMS IN FOOD
The physical and chemical properties of any food determine the type of micro-organisms that will grow and reproduce. When micro-organisms or their spores get in contact with food, such food gets contaminated and when consumed man can have adverse effect on the individual.

CAREER OF MICRO-ORGANISM
Vectors
Alternative of hosts primary host, secondary host
Mechanical and biological methods
Disease causing microbes carried by vectors

Apart from the various means through which microbes get into our body already discussed, there are certain organisms that carry micro-organisms that can affect man negatively about. These organisms are called Careers are usually insects and mammals. The hairy nature of the insect body traps the microbes and gets carried from place to place. The natural habitats of these insects include latrines, food stores, dung hills and other similar places where microbes abound. The careers pick up the pathogens and bring them to exposed human food. As they land on these exposed food to feed on them, the microbes are transferred to the food which could be eaten by man and consequently bring about infection and diseases. These careers are called Vectors. The pathogen neither grow nor affect them adversely hence, they are called Vectors. Vectors are primary to the pathogen while man is the secondary Host.

EVALUATION
 What are careers? Give two examples.
 State the habitat of the career named above.


Streptococcus Bacteria
This scanning electron micrograph shows disease-causing Streptococcus bacteria, commonly found in the human mouth, throat, respiratory tract, bloodstream, and wounds. Often airborne in hospitals, schools, and other public places, Streptococcus bacteria are responsible for infections such as strep throat, scarlet fever, and some types of pneumonia.

Location of Micro-organisms in Careers
Organisms that carry micro-organisms are called Vectors. Diseases caused by career do not affect the vector that carries them.
The micro-organism found in vector lives in them temporarily for the purpose of developing to the stage where they can effectively infect man. Thus the pathogens have two hosts. This phenomenon is killed alternation of hosts. The vector is the primary host while man is the secondary host of the pathogen. Mosquitoes, Tsetse fly are examples of vectors of microorganism do not develop inside the housefly. Instead the body of the housefly’s body “collects” micro-organisms as it parches on exposed human food to feed on it, the microbes (bacteria) falls off its body onto the food which causes disease unto man when contaminated food is eaten.
Though biting and sucking man’s blood, Anopheles Mosquito transmits a protozoan – plasmodium into mans blood causing disease – malaria. The pathogen is in the gut of the insect and as it feeds on the blood of man, it deposits it into man.

EVALUATION
1. Define the following terms: (i)natural microflora (ii) pathogen (iii) careers (iV) vectors
2. Name and describe the two methods by which pathogens are carried from place to place.
3. (a) List the important groups of micro-organisms and give one example from the group.
(b)What is culture?
(c)Outline the steps you will take in preparing a culture solution.

GENERAL EVALUATION
(Objectives)
1. One of the micro-organisms cannot exist on its own (a) bacterium (b) an algae (c) a virus (d) fungus (e) protozoa
2. Which of the following can be grown only in a tissue culture? (a) a virus (b) a bacteria (c) an algae (d) a fungus (e) a protozoan.
3. Which of the following statements is false? (a) micro-organisms exists in water and air (b) micro-organisms exist inside very small organisms (c) micro-organisms exists inside bodies (d) hand lens can be used to observe and study micro-organisms (e) housefly are expanded of vectors
4. Micro-organisms are important in recycling nutrients because; (a) they are capable of multiplying by space of formation (b) many of them are parasites (c)they are many and are found everywhere (d) they are capable of breaking dead organic material (e) they can multiply very quickly
5. Facultative bacteria are ----- (a) unable to survive in aerobic environment (b) unable to survive in anaerobic environment (c) can only survive in aerobic environment (d) can survive in both aerobic and anaerobic environment (e) none of the above
ESSAY QUESTIONS
1a. what do you understand by micro-organisms?
b. Describe how micro-organisms enter our bodies with examples and steps preventing them.
c. list the groups of micro-organism with examples.
2a. List micro-organisms found in water with examples.
b. micro-organism in 2a can be grouped into 3, name these groups with short explanations.
c. A group of aquatic micro organisms are known as primary producers explain.
3a. what is culture?
b. What steps are entails in preparing a culture solution
c. Outline precautions to observe in preparing a culture solution.
4a. Describe an experiment to show that atmospheric Air contains micor-organisms.
b. What are the functions of natural normal micrflora in and on human body?
c. List two insects and three mammalian vectors, stating the following for each organism: (i) micro-organisms (ii) Disease caused (iii) possible control of spread
5a. Define the following terms: (a) natural microflora (ii) pathogen (iii) careers (iv) vectors
b. Write short notes on the importance of micro-organism to man in the area of (i) medicine (ii) agriculture

SUGGESTED PRACTICALS:
1. Preparation of culture solution
2. Examine the presence of microbes in Air, water, saliva, under nail.
3. Classification of bacteria using different criteria
REFERENCES
1. Senior secondary Biology 1. By FOC Ndu, P.Asun, J.O Aina
2. Biology for Senior Secondary Schools I By O.S. Obayori, P.O. Balatiri, L.B. salam
3. Modern Biology for Senior Secondary Schools By Sarojimin T. Ramalingam