THIRD TERM E-LEARNING NOTE

SUBJECT: BIOLOGY CLASS: S. S. ONE

SCHEME OF WORK

THIRD TERM SCHEME OF WORK FOR SSS ONE

BIOLOGY

TEACHER; MR. ANDREW C. EZEJI

WEEK TOPIC BEHAVIOURAL OBJECTIVES; At the end of the lesson, students

should be able to:
1. BASIC SCOLOGICAL CONCEPTS -Define ecology
-Ecological concepts. -State the two main branches of ecology
-Components of an ecosystem -Explain the following ecological concepts ; Environment, biosphere,
lithosphere, hydrosphere, atmosphere, habitat, ecological niche, biotic
community and ecosystem.
-State the two main components of the ecosystem (biotic and abiotic)
-Describe the interaction between the abiotic and biotic components of the
ecosystem.

2. LOCAL BIOTIC COMMUNITIES IN -State the characteristics of the following

NIGERIA Mangroove swamp forest,Tropical rain forest,Southern Guinea
-Mangroove swamps forest Savannah,Northern Guinea Savannah ,Sahel Savannah,Desert
-Tropical rain forest - Locate these local biomes in the map of Nigeria
-Southern Guinea Savannah
-Northern Guinea Savannah
-Sahel Savannah
- Desert
3. MAJOR BIOMES OF THE WORLD -State the characteristics of the following
-Tropical rain forest Tropical rain forest, savannah, desert, shrubs, Afro alpine,swamps
-Savannah - Locate these biomes on the map of the world
-Desert
-Shrubs
-Afro alpine
-Swamp
4. POPULATION STUDIES -Explain population size, dominance, density, frequency distribution and
-Population size percentage cover
-Dominance - Enumerate the factors affecting population.
-Density -Measure physical factors affecting population using measuring
-Frequency distribution instruments.
-Percentage cover -Identify ecological factors of aquatic habitat, terrestrial habitat and both.
-Factors affecting population -Estimate population of an area using either quadrat method, sweep netor
- Use of sampling methods in transect method
population studies.
5. FUNCTIONING ECOSYSTEM AND -Define the terms ; autotrophy and heterotrophy
ENERGY TRANSFORMATION - Recognize that food relationship exist among living things.
- Autotrophy and heterotrophy -Correctly define food chain, food web,trophic level and ecological
-Feeding relationship pyramid.
- Laws of thermodynamics - Describer the nature of energy transfer in the ecosystem.
 Application of both laws to ecological -State the two laws of thermodynamics.
phenomenon. - Explain the application of the laws in ecological phenomenon.
6. MICRO ORGANISMS AROUND US - Define micro organisms.
-Definition of micro organisms -Identify micro organisims that can be found in air, water, inside and on
- Identification of micro organisms human beings.
present around us. - State the five classes of micro organisms.
-Classification of micro organisms -Enumerate beneficial effects of micro organisms.
-Beneficial and harmful effects of
micro organisms on living things
7. DISEASES AND IMMUNITY - Describe pathogens
- Definition of pathogen -Enumerate the examples of transmissible and non transmissible diseases.
- Transmissible and non transmissible -Describe the body defenses to diseases.
diseases. -Explain the factors that control the spread of diseases
-Factors that control the spread of -Describe active immunity, outlining the process of vaccination.
diseases. -Explain passive immunity and the role of breast feeding in fighting
-Body defenses against diseases diseases in infants.
- Active immunity
-Passive immunity
8. TOWARDS BETTER HEALTH -Describe some ways by which pathogens and diseases can be controlled.
- Control of harmful micro organisms. -State ways of controlling vectors.
- Vectors: |definition and ways of Describe methods used in disposal of refuse and sewage.-
controlling them.# - Enumerate ways of ensuring good health by individuals .
-Maintenanace of good health -Name national and international health organisations
- Provide descriptions of what they do
11. Examination Examination

REFERENCES
 Modern Biology for Senior Secondary Schools by S.T. Ramlingam
 Essential Biology by M.C Michael
 New Biology by H. Stone and Cozen
 SSCE, past questions and answers
 New System Biology by Lam and Kwan
 College Biology by IdodoUmeh
 UTME, SSCE and CAMBRIDGE past questions and answers
 Biology practical text
 WEEK ONE
DATE………………………
TOPIC: BASIC ECOLOGICAL CONCEPTS
CONTENT
 Definition and Branches of Ecology
 Ecological Terms ( Environment, Biosphere, Habitat, Ecological Niche, Population,
Community, Ecological System, Biome)
 Components of an Ecosystem
BASIC ECOLOGICAL CONCEPTS
DEFINITION OF ECOLOGY
Ecology is the study of plant and animals (as well as microorganism) in relation to their
environment. As a practical science, ecological studies involve:-
 Studying the distribution of living organisms
 Finding out how living organisms depend on themselves and their non-living
environment for survival.
 Measuring factors affecting the environment.

BRANCHES OF ECOLOGY
Depending on whether the organisms are studied alone or in groups, ecology is divided into two:
i. AUTECOLOGY: This is the study of an individual organism or a single species of
organism and its environment e.g. the study of a student and his school environment.
ii. SYNECOLOGY: This involves studying the inter-relationships between groups of
organisms or different species of organism living together in an area e.g. study of fish, crabs,
seaweeds, etc in a pond.

EVALUATION
1. Define ecology.
2. Differentiate between the two branches of ecology.

ECOLOGICAL TERMS
The various concepts closely associated with ecology include;
a. ENVIRONMENT
This includes external and internal factors, living or nonliving which affects an organism or a
group of organisms. These include the habitat (with its peculiar physical conditions e.g. light,
food, water, air), the animals preying on other animals or the diseases affecting the organism.
b. BIOSPHERE (ECOSPHERE)
This is the zone of the earth occupied by living organisms so as to carry out their biochemical
activities.
The ecosphere consists of 3 major portions:-
 Lithosphere:- this is the solid portion (the outer-most zone) of the earth which is made
up of rocks and minerals. This zone forms 30% of the earth surface and it is the basis of
human settlement.
 Hydrosphere:- this is the liquid (aquatic) part of the biosphere. It covers about 70% of the
earth’s crust. It consist of water in various forms; solid, liquid or gas (water vapour),
hydrosphere includes lakes, pools, spring, oceans, ponds, rivers, etc.
  Atmosphere: - this is the gaseous portion of the earth. It consists of three main gases;
nitrogen (78%), oxygen (21%) and carbon (iv) oxide (0.03%). There are also 0.77% rare
gases.
c. HABITAT
This is a place where an organism is naturally found. Habitat is always affected by
environmental factors. Habitat can be divided into three:-
 Aquatic habitat: this is where plants and animals (as well as micro organisms) live in
water e.g. Sea, ocean, lagoons, streams, etc.
 Terrestrial habitat: this is where the organisms live on land e.g. forests, grassland,
(savanna), desert etc.
 Arboreal habitat: These include tree trunks and tree tops where some organisms (usually
animals) are naturally found.
d. ECOLOGICAL NICHE
This refers to the habitat and the entire habit (behavioural, feeding, breeding) of an organism. It
is the physical space occupied by an organism and its functional role in the community.
e. POPULATION
This is the total number of organisms of the same species living together in a habitat e.g.
population of cockroaches in Biology laboratory.
f. COMMUNITY
This is made up of all the populations of living organisms that exists together in a habitat e.g. a
community of decomposer, insects and birds on a decaying log of wood.
g. ECOLOGICAL SYSTEM (ECOSYSTEM)
This refers to the basic functional unit in nature, which consists of all living factors and their
interaction with non-living factors of the environment. An ecosystem can be natural or artificial.
h. BIOMES
This is a large natural terrestrial ecosystem. It is a plant and animal community produced and
maintained by the climate.

EVALUATION
1. Define the following A. Community B. Population C. Ecosystem
2. Differentiate between Biosphere and Ecosystem.

COMPONENTS OF AN ECOSYSTEM
Biosphere comprises of various ecosystems. There are two main components of the ecosystem,
the abiotic and the biotic components.

ABIOTIC COMPONENTS
These are non-living components and they are basic elements and compounds of the
environment in which an organism lives.

Abiotic components include organic substances (e.g. carbohydrates, lipids, and proteins),
inorganic substances (e.g. CO2, H2O), climatic factors (e.g. light, temperature, rainfall) as well as
edaphic factors (e.g. soil types, texture, topography etc).
BIOTIC COMPONENTS
These are the living things in the ecosystem. These include the producers, the consumers and the
decomposers.
a. Producer: These are autotrophs in that they synthesize their food from simple inorganic
substances e. g. green plants, protophytes and chemosynthetic bacteria.
b. Consumers: These are heterotrophs which feed on the producers or one another. They
may be primary, secondary or tertiary consumers e.g. non-green plants, animals protozoa and
some bacteria
c. Decomposers: These are saprophytes. They break down remains of plants and animals
and release usable nutrients to the soil. These nutrients are used by plants to make food e.g. fungi
and some bacteria
Generally living things influence other living things in many ways such as in feeding
(parasitism), shading from sunlight, pollination and dispersal of seeds, competition. Some of
these factors are favourable while others are unfavourable.

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. Write a short note on ecosphere.
2. Differentiate between a habitat and ecological niche.
3. With two example each, state three subdivisions of habitat.
4. What is a population?
5. How is population related to the community?
6. Differentiate between ecosystem and biomes.
7. State the two major components of an ecosystem with two examples each.

READING ASSIGNMENT
College Biology, chapter 23, 496 – 499

WEEKEND ASSIGNMENT
1. Which of the following is not classified as a terrestrial habitat? A. forest B. guinea
savanna C. literal zone D. desert
2. The activities of an organism which affect the survival of another organism in a habitat
can be described as A. biotic factors. B. Abiotic factors C. climatic
factor D. edaphic factors.
3. The number of individuals of the same species interacting in a habitat at a particular time
is best described as A. community B. ecosystem C. population D. biome.
4. A biotic community with its physical environment (abiotic factors) defines A.
ecosystem B. population C. habitat D. biosphere.
5. The most abundant gas in the atmosphere is A. oxygen B. nitrogen C. carbon
dioxide D. a rare gas.

THEORY
1. Define i) Biotic community ii) habitat iii) an ecosystem
2. Write short notes on the three major portions of ecosphere.
WEEK TWO DATE ………………………
TOPIC: BIOMES
CONTENT
 Biomes
 Local Biomes
 World Biomes
BIOMES
Biomes are large natural terrestrial ecosystem, identified by their dominant vegetation. They are
terrestrial because plants form the bulk of the community in any ecosystem e.g. a forest biome
has densely packed tall trees while grasses and few scattered shrubs are found in a savanna
biome. Climatic factors determine the type of vegetation in a biome. These factors may include
rainfall, relative humidity, temperature, wind and light.

EVALUATION
1. What is a biome?
2. Mention four factors that determine the vegetation of a biome.

LOCAL BIOMES
The local biomes particular to Nigeria include the following:
 mangrove swamp
 tropical rain forest
 savanna (northern and southern Guinea savanna, Sudan savanna and sahel savanna)
a. MANGROVE SWAMPS
These are found in the tropics along coastal region and river mouths. Mangrove swamps are
forest of small, evergreen, broad-leaved trees growing in shallow, brackish water or wet soil.
Many mangrove trees have pop roots and breathing roots called pneumatophores. The climate
here is hot and wet, with total annual rain fall of above 250cm and temperature of about 260c. In
Nigeria, mangrove swamps are found in the delta region of Lagos, Delta, Rivers, Bayelsa and
Cross rivers states.
b. TROPICAL RAIN FOREST:
This occurs in the region that is between the equator and latitude 50-100N and S. It has the
following characteristics:
 The forest are mainly lowland.
 The climate is hot and wet.
 It consists of broad leaved trees that are mostly ever green; the leaves are gradually shed
throughout the year and replaced by new ones.
 The trees form canopy strata with their interior having low light intensity, high humidity
and damp floor.
 The trees possess thin bark.
 The forest is rich in epiphytes and wood climbers.
 The annual rainfall and temperature are 200cm and 270c respectively.
In Nigeria, tropical rainfall is found in Edo, Delta, Ondo, Imo, Lagos, Rivers state e.t.c.
c. SAVANNA
These are tropical grassland in Africa. They are usually flat for miles at a stretch and made up
mainly of grasses. The savanna region has a hot and wet seasons (290c) which alternate with a
cool and dry season (180c). The total annual rainfall around 50cm-150cm. During the dry season,
the grasses are usually dry and brown and bush fire is common occurrences.
South Guinea savanna (the largest of all the biomes in Nigeria) has tall grasses with scattered,
deciduous trees. It is found in Enugu, Kogi, Benue, Kwara, Oyo, Osun, Ekiti State etc.
Northern Guinea Savanna has scattered, deciduous trees, sometimes with thorns and tick barks.
Grasses are short and numerous. it is found in plateau, Kaduna, Bauchi, Niger, Kano, Adamawa
states etc.

Sudan savanna has the shorter grasses fewer trees which are more scattered. It is found in Kano
and parts of Borno, Sokoto, Niger, Bauchi states e.t.c

Sahel savanna has high temperature and low rainfall with short and scanty grasses as well as
short and tough shrubs or trees. The plants are drought-resistant. It is found in Borno, Kastina,
Sokoto, Yobe, Kano, Jigawa states etc.

EVALUATION
1. In a tabular form, distinguish between the three major biomes in Nigeria using the
following
a. Total annual rainfall
b. Temperature
c. Regions found
2. List five characteristics of savanna.

WORLD BIOMES
Of all abiotic factors affecting ecological system, temperature and rainfall determine the world
biomes. The biomes include: tropical rain forest, temperate forest, coniferous forest, temperate
shrubland, savanna, temperate grassland, desert, and tundra and mountain vegetation.
a. TEMPERATE FORESTS
These are forests with the following characteristics they are
 Mainly of broad leaved deciduous trees which shed their leaves during winter.
 Possession of moderately wet climate with a dry or cold season.
b. CONIFEROUS FORESTS
These are characterized by
 Needle-leaved evergreen conifers such as pines, firs.
 Possessing few trees.
 Possessing tall tree forming upper storey.
 The forest floor being covered with a thick layer or conifer needles.
 Possessing cool temperature climate with light rainfall and snow.
c. TEMPERATE SHRUBLAND
This is forest with the following characteristics
 It consists of drought-resistant shrub plants and dwarf trees, often fire-resistant e.g.
marquis.
 It has temperate climate with low rainfall.
d. TEMPERATE GRASSLAND
This is characterized by:
 perennial grasses grow on very fertile soil to support herds of grazing mammals
  It has moderately dry climate with a cold winter and a hot summer
e. SAVANNA
This is a tropical grassland with:
 scattered trees and often infertile soil
 moderately dry climate with a warm dry season and a hot rainy season
f. DESERT
This has:
 very sparse vegetation, with succulent perennials that have deep root systems.
 tropical temperate and afro-alpine regions with less than 25 cm annual rainfall.
g. TUNDRA
This is characterized by:
 treeless marshy vegetation composed mainly of dwarf shrubs, grasses, lichen and moss
with very few plant trees.
 cold climate with long icy winter and very short summer with an average temperature of
100c.
h. MOUNTANE VEGETATION
This has:
 evergreen rainforest on slopes of mountain, these forest are less luxuriant than the
tropical rainforest.
 Afro alpine vegetation occurs at heights above 3000m on mountain, vegetation consists
mainly of heath, grasses and sedges.

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. What do you understand by the term biome?
2. State the local biomes found in Nigeria.
3. State the four savannas present in Nigeria.
4. What are the two factors that determine the world biomes?
5. State four of the world biomes with two characteristics each.
6. Using their characteristics, differentiate between savanna and desert.

READING ASSIGNMENT
College Biology, chapter 23, page 499 - 504

WEEKEND ASSIGNMENT
1. How is savanna plants protected from bush fires? They have A. sunken stomata B. thorn
bark C. thick barks D. soft leaves
2. Which of the following limiting resources is competed for by organisms in the desert?
A. Light B. oxygen C. temperature D. water
3. Which of these is not a true characteristic of the tropical rain forest? A. Vegetation
consists predominantly of tall tree with thick canopy B. forest is rich in epiphytes and climbers
C. annual rainfall is less than 100 cm D. annual temperature is 270c
4. Which of the following does not describe the coniferous forest? A. needle leaved
evergreen conifers B. broad leaved evergreen conifers C. possessing few trees
D. possessing cool temperate climate
5. Montane vegetation is described by the following except A. treeless marshy vegetation B.
evergreen rainforest on slopes of mountain C. forest are less luxuriant than tropical rain forest D.
afro alpine vegetation at heights above 300m on mountain

THEORY
1. Outline the properties of the savanna as a world biome.
2. State four characteristic features of vegetation found in A. savanna B. tropical rainforest
C. desert.
WEEK THREE DATE
……………………
TOPIC: POPULATION
CONTENT
 Population Characteristics
 Population Studies
 Factors that Affect Population
 Simple Measurement of Ecological Factors.
POPULATION CHARACTERISTICS
These include population size, density, frequency, percentage cover and distribution.
a. Population size: - this is the number of organisms of the same species living together in a
given area at a particular time.
b. Population density: - this is the number of a particular species per unit area or volume of
the habitat. Therefore
Population density = population size / area of habitat.
c. Population frequency: - this is the number of times an organism occurs within a given
area or habitat.
d. Percentage cover: - this refers to how much space or area an organism occupies its
habitat.
e. Population growth rate: - this refers to the net result of the influence of natality (birth
rate) and mortality (death rate) of organism in a given habitat.
f. Population distribution: - this refers to the ways in which individuals of the same species
are arranged in a given habitat, either randomly, evenly or clumped.

EVALUATION
1. Define the following terms: (i) Percentage cover (ii) Population size (iii) Population
frequency (iv) Population density.
2. Mention two methods of determining population size.

POPULATION STUDIES
a. Choose the habitat.
b. Select the sampling method to be used.
c. Collect, count and record the different types of organisms present. Sampling using a
quadrant or transcent using a tape can be adopted.
d. Identify the dominant species i. e. the species that has greater influence on the other
members of the community.
e. Repeat the population studies at intervals.
f. Determine the population characteristics.

EVALUATION
1. How do you determine the population density of insect on a piece of land?
2. How do you determine the population of grasses in a piece of land?

FACTORS AFFECTING POPULATION

a. Natality; Ability of organisms to reproduce to increase its population
b. Mortality; Death rate.
c. Immigration; Movement of organisms from different habitats into a new habitat and this
increases the population of the new area, decreasing the population of the former habitat.
d. Emigration; Movement of organisms out of a habitat due to unfavourable conditions e.g.
food scarcity etc. This reduces the population of the habitat.
e. Availability of food; Animals tend to migrate to where there is plenty of food, thereby
increasing the population of such places.
f. Seasonal climatic changes; whether the change is favourable or not determines the stay or
migration of organisms into or out of a habitat.
g. Breeding season; some organisms move out of their habitats during this season (e.g.
fishes); hence the population drops.
h. Natural disasters; Like fire, drought, floods, earthquakes etc lead to a decrease in
population through the death of organisms out of such habitat

MEASUREMENT OF ECOLOGICAL FACTORS

These factors can be measured using some instruments as shown below.
INSTRUMENTS USES
a. Photometer Light intensity
b. Hydrometer Light intensity in water
c. Wind vane Direction of wind
d. Anemometer Speed of wind
e. Rainguage Amount of rainfall
f. Hygrometer Relative humidity
g. Barometer Pressure
h. Glass thermometer Temperature
i. Colorimeter or pH scale Acidity / Alkalinity
j. Secchi disc Turbidity
k. Sweep insect net Catching insects

EVALUATION
1. State three factors that: a) increase the population of a habitat b) decrease the population
of a habitat.
2. Explain the effect of bush burning on the population.
3. List five ecological instruments and their uses

GENERAL EVALUATION/REVISIONAL QUESTIONS

1. State the two components of an ecosystem
2. With two examples each, discuss the various biotic components in an ecosystem
3. State three factors that: a) increase the population of a habitat b) decrease the population of
a habitat.
4. State five effects of over population in a
community
5. State two Abiotic factors unique to: a) aquatic habitat b) terrestrial habitat.
6. List five measurable ecological factors.
7. State the ecological instruments used in measuring the factors listed above.
READING ASSIGNMENT
College Biology, chapter 23, page 530 - 532

WEEKEND ASSIGNMENT
1. Climatic factors in an ecosystem include the following except
A. light B. wind C. temperature D. Oxygen.
2. Organic part of abiotic component of an ecosystem includes the following
except A. water B. carbohydrate C. Protein d) Lipids
3. The ratio of population size to the area of the habitat is called A. population
size B. population density C. population frequency D. population cover.
4. Habitat factors include all the following except A. biotic B. abiotic C. edaphic D. nature.
5. The total number of organisms of the same species in a habitat at a particular time is
called A. population B. community C. census D. all of the above

THEORY
1. List five ecological instruments and state their uses.
2. State five factors affecting a population size.
WEEK FOUR DATE: …………
TOPIC: FUNCTIONING ECOSYSTEM
CONTENT
 Feeding Relationship
 Trophic Levels
 Food Chain and Food Web
 Energy Flow and Ecological Pyramids
 Energy Transformation in Nature
 Laws of Thermodynamics
FEEDING RELATIONSHIPS
Since all living organisms must obtain energy and nutrients from the environment in order to
remain alive, they are into feeding relationships. This makes an ecosystem a functional unit. All
organisms fall into one of the three major groups of biotic community, namely: producers
(autotrophs), consumer (heterotrophs) and decomposers
a. The autotrophs provide food for other organism in the habitat. In terrestrial habitat, they
include grasses, trees and shrubs while aquatic autotrophs include phytoplankton, seaweeds etc
b. The heterotrophic include: (i) herbivores (called primary consumers) feeding on plants,
carnivores (called secondary consumers) feeding on primary consumers and omnivores is other
animals called (tertiary consumers) that feed on secondary consumer or on both. Terrestrial
heterotrophs include cow, dog, lion, man etc while water fleas, tadpoles, larvae of insect and fishes
are aquatic heterotrophs
c. Decomposers like termites, larvae of housefly (maggot), bacteria and fungi break down
dead organic matter to release simple chemical compounds which can be absorb and use again.
Of all the three biotic groups, consumers have better chance of survival than any other in an
ecosystem.

EVALUATION
1. State two examples each of the following in both terrestrial and aquatic
habitat A. Autotrophs B. heterotrophs C. Decomposers.
2. How do the three groups of organisms in one above relate?

TROPHIC LEVELS
In an ecosystem, energy and nutrients are transferred step by step among organisms along a feeding
path way. The feeding pathway in all ecosystems follows a similar pattern which is as
follows:
a. It begins with a producer e.g green plant like grass.
b. The producer is eaten by a primary consumer e.g Zebra , goat.
c. The primary consumer is eaten by a secondary consumer e.g. lion.
d. Decomposers convert the remains of dead producers and consumers into simple inorganic
substance which return to the non –living environment. The difference in the feeding pathways
within an ecosystem or between different ecosystems is the termination of the pathway. Some may
end at the primary consumer step or may go on to secondary consumer, tertiary consumer etc.

Trophic (feeding) level: is each step along a feeding pathway. The order in which the trophic
levels are arranged gives the path of energy (food) flow among the functional groups of
organisms. The trophic levels are numbered in ascending order, starting from one to indicate the
path of energy flow.

Trophic level 1 always consists of producers or autotrophs, trophic level 2 always consists of
primary consumers. Above trophic level 2, consumers could be carnivores, parasitic organisms
and scavengers. The final consumers eventually die and are fed upon by decomposers.

EVALUATION
1. Describe the pattern that feeding pathway follow in all ecosystems.
2. What do you understand by feeding level?

FOOD CHAIN FOOD WEB

This is the feeding relationship involving the transfer of energy through food from producers to
consumers in a linear form.

Examples of food chain in terrestrial habitats are:

Grass zebra lion
(Producer) (Primary consumer) (Secondary consumer)

Guinea
grass grasshopper toad snake hawk
(producer) (primary consumer) (secondary consumer) (tertiary consumer)

In aquatic habitats are:

Spirogyra tadpoles crabs kingfish
(producer) (primary consumer) (secondary consumer) (tertiary consumer)

Diatoms mosquito larva Tilapia fish whale

(producer) (primary consumer) (secondary consumer) (tertiary consumer)

Therefore, in a food chain, food energy is transferred from one organism to another in a linear
form. Most food chains begin with producers but few of them start with dead plants or animals
e.g
Humus earthworm domestic fowl man

Numerous food chains present in an ecosystem produce a food web.

FOOD WEB: - is a complex feeding relationship among organisms in the same environment
with two or more interrelated food chains. Food webs therefore contain more organisms than
food chains. A single plant could be fed upon by more than one or two organisms
In an ecosystem, a consumer has a better chance of survival because it feeds on different types of
plants or animals in a food web.
EVALUATION
1. What is a food chain?
2. Draw a food chain involving four trophic levels in a A. marine B. terrestrial habitat.

ENERGY FLOW AND ECOLOGICAL PYRAMID

Pyramids are diagrammatic representations used in ecology. They include pyramid of number,
pyramid of energy and pyramid of biomass.
1. PYRAMID OF NUMBER: this refers to the numbers of individual organisms at each trophic
level, decreasing from the first to the last level in a food chain.
Pyramid of number has the following defects: The individual organisms is given the same status,
though they varied greatly in size e. g. grass and trees grouped together as producer and is not
drawn to scale.

2. PYRAMID OF ENERGY: This is the amount of energy present in the living organisms at
different trophic level of a food chain, which decreases from the first to the last i. e. from the
base of the pyramid to the apex.
3. PYRAMID OF BIOMASS: Biomass refers to the size and numbers of living organisms.
It represents the total wet or dry mass of the organisms in each trophic level. This gives a more
accurate picture of the relationship between the organisms at various trophic levels in a food
chain than the pyramid of numbers.

ENERGY LOSS IN THE ECOSYSTEM

Energy is the ability to do work. All living organisms obtain energy from the food they eat. The
food is produced by green plants and other organisms depend on them. As energy is passed from
one organism to another along the food chain, it is progressively lost due to respiration (energy
used for various metabolic activities) and as heat. In most ecosystems, only about 1 - 10% of the
solar energy may be available to photosynthetic producers.
 EVALUATION
1. What is a pyramid? State three types of ecological pyramids.
2. State the similarities between pyramid of numbers and pyramid of energy.

LAWS OF THERMODYNAMICS
Thermodynamics simply means heat change. Heat as a form of energy that is subject to change in
living organisms is governed by two laws
a. First law of thermodynamics which states that energy can neither be created nor
destroyed, although it can be changed from one form to another. E.g. chemical energy in food is
converted to kinetic energy and heat energy in our muscles when we walk or run.
b. Second law of thermodynamics which state that in any conversion of energy from one
form to another, there is always a decrease in the amount of useful energy i. e. no transformation
of energy from one state to another is ever 100 percent efficient.
During metabolic activities, some chemical energy is constantly lost as heat energy from the body
of an organism. As energy is converted from one form to another, there will always be a loss.

FOOD CHAIN AND LAWS OF THERMODYNAMICS

i. Using the first law: in a food chain, energy from the sun is transferred from the producer
to the final consumer and the sum total of the energy remains constant.
ii. Using the second law: as the energy is transformed from one trophic level to another, part
of it is converted into heat it is lost, among a progressive drop in energy in successive trophic
levels.

PYRAMID OF ENERGY & LAWS OF THERMODYNAMICS

(i) Using the first law: The energy of the producers at the base of the pyramid is higher and it is
gradually transformed to other trophic levels.
(ii) Using the second law: As energy is transferred from one trophic level to another, part of the energy
is converted to heat.

ENERGY FLOW AND LAWS OF THERMODYNAMICS

(i) Using the first law: Energy flows from producers to 10 consumers, then to 20 consumers and finally
to 30 consumers in a food chain. The energy flow in a food chain is therefore in one direction only.
(ii) Using the Second law: Energy transfer between trophic levels is not 100%. Successive levels have
less useful energy and so can only support fewer organisms. Produce (green plants) have the
highest amount of energy. When herbivores feed on the plants, the energy level is reduced. When
carnivores consume the herbivores, the energy level is reduced.

EVALUATION
1. State the laws of thermodynamics and explain.
2. Explain pyramid of energy and food chain using the laws of thermodynamics.

GENERAL EVALUATION
1. What is a food chain?
2. Explain the role of the following in a food chain (i) Producer (ii) Consumer (iii)
Decomposer.
 3. A.Draw a food chain involving four trophic levels in a marine
habitat. B.Explain (i) the flow of energy through the food chain drawn in
3C (ii) how energy in the chain is lost to the environment.

READING ASSIGNMENT
College Biology chapter 23, page 544 – 551

WEEKEND ASSIGNMENT
1. The ultimate source of energy in nature is A. green plants B. moon C. star D. sun
2. The usable form of energy in animals is A. chemical energy B. kinetic energy C.
potential energy D. ATP
3. Available to photosynthetic plants is ________ of the solar energy. A. 1-5% B. 2-5%
C. 5-15% D. 1-10%
4. The study of the relationship between heat energy and other forms of energy is
called_____________. A. thermodynamics B. thermocouple C. thermosetting D. all of the
above
5. Energy can neither be created nor destroyed but can only be changed from one form to
another This refers to the A. first law of thermodynamics B. second law of
thermodynamics C. third law of thermodynamics D. none of the above

THEORY
1. State the first and second law of thermodynamics.
2. In a tabular format, state four differences between food chain and food web.
WEEK FIVE DATE: ……………………………

MICRO-ORGANISMS AROUND US
CONTENT
 Description and Groupsof Microorganisms
 Concept of Culturing
 Identification of Microorganisms
 Carriers of Microorganisms

DESCRIPTION AND GROUS OF MICROORGANISMS

Micro-organisms otherwise called microbes or germs can be defined as living things which
cannot be seen with unaided eye but by the use of microscopes.
They exist almost everywhere, in water, air, soil, surface of objects, as well as on and within
living organisms. They are carried by air currents from the earth’s surface to the upper
atmosphere. They occur most abundantly where there is food, moisture and adequate temperature
for their growth.
It was the invention of microscope that opened the gateway to the world of these minute living
organisms. The first person to discover microbes was a Dutch man called Anthony Leeuwenhoek
(1632-1723). Using a simple microscope, he was astonished to discover that rain water that had
been collected from pools was full of little organisms.
GROUPS OF MICRO-ORGANISMS
Micro-organisms include all viruses, bacteria and the protists. Others are the cyanobacteria,
certain fungi and algae.
1. BACTERIA: These are minute unicellular organisms or simple association of similar
cells which multiply by binary fission. Most bacteria cells range between 0.2 µ-2µ in
diameter and 0.0005mm-0.002mm long. Each bacterium cell has a cell wall with
cytoplasm. There is no well defined nucleus. Consequently, they are prokaryotic
organisms.
There are different kinds of bacteria showing a range of shapes. Certain kinds of bacteria
have long thread-like structures called flagella which assist in locomotion. Bacteria with
spherical shape are referred to as cocci (singular-coccus). There are several forms as
shown on the next page.
Streplococci- These are arranged in chains. They cause sore throat.
Staphylococci- These stick together to form irregular bunches. They cause boils.
Diplococci- They occurs in pairs. e.g. pneumococci which causes pneumonia.
Bacilli- They is rod-shaped. They cause typhoid fever.
 Spirilla (singular = spirillum)- These are rod-shaped bacteria twisted into a spiral shape.
Spirochaetes- These are also spiral in shape but are more flexible and slender with
helically coiled structure e.gTreponemapallidum which causes syphilis.
Vibrios- These are comma-shaped bacteria e.gVibriocholera which causes cholera.
2. VIRUSES: Viruses are a large group of pathogens whose presence is felt only when
they are in contact with living cells. They are very small and vary between 0.1µ-0.25 µ in
diameter. The largest virus is less than one-fourth the size of typhoid bacterium.
A virus consists of a nuclear material either DNA or RNA, enclosed within a protein coat.
Outside living organisms they are like complex chemicals.
3. PROTISTS: These are single-celled animals, mostofwhich are only visible by means of
microscope. They are common in fresh water and moist soils. Examples include Euglena,
Paramecium, Trypanosoma, Plasmodium, etc.
4. FUNGI: They are diversified in form. The blue and green growth on oranges,
lemons, cheese and the white/grey growth on bread are usually signs of fungal infections.
Fungi feed saprophytically. Examples of fungi include Mucor, Rhizopus, Penicillium,
Aspergillus, etc.
5. ALGAE: Most algae are unicellular and very small. They have chlorophyll. They
occur abundantly in water, moist soils, bark of trees, stones, etc. Free floating microscopic
algae are referred to as phytoplanktonsand they form the major food of aquatic animals.
Examples of unicellular algae include Chlamydomonas and Protococcus.

Shapes of bacteria
EVALUATION
1. What are microorganisms
2. List five groups of microorganisms with two examples each

CONCEPT OF CULTURING
A pre-requisite to studying microbes is their cultivation under laboratory conditions. Hence, it is
important to know the nutrients and physical conditions needed by the organisms.
It is easier to grow bacteria, fungi, and algae in appropriate media. The material on or in which
microbes grow in the laboratory is called culture medium. Some media are prepared from
complex extracts of plant or animal tissues. A culture is the population of organisms cultivated in
a medium.
If a culture contains only one living species of organism regardless of the number of individuals,
it is said to be a pure or axenic culture. A culture which contains two or more species growing
together is called a mixed culture.
An important medium used for growing microbes is agar. It is a dried polysaccharide extract of
red algae which is used as a solidifying agent. It is not broken down by microbes.

EVALUATION
1. What is a culture medium?
2. Differentiate between axenic and mixed culture

IDENTIFICATION OF MICRO-ORGANISMS
There are many ways of identifying micro-organisms around us. These include the use of
microscopes stains of different types, types of colonies formed by the microbes, their food
requirement and oxygen requirement of the organisms.
To determine the presence of microbes around us, suitable media are used to culture them in
petri-dishes which are first sterilized by heating them in a pressure cooker, autoclave or oven.
Micro-organisms are not capable of growing in the air. The exposure of nutrient agar to the air
will show the growth of different bacteria colonies in the air. Microbes commonly found in the
air include viruses, bacteria, fungi, etc.
Microbes in aquatic habitat may be grouped into natural water, soil and sewage microbes.
Examples of the first category include protists, algae, some fungi,bacteria, etc. Examples of the
second group include Rhizobium, Nitrosomonas, and Nitrobacter. Examples of sewage microbes
are Entamoebahistolytica, Escherichia coli, etc.
Microbes living in our bodies form normal population without causing any harm. However,
under certain conditions, they may become dangerous. Pathogenic organisms cause diseases
when body resistance is low or when normal microflora is de-established by the use of
antibiotics. Any food item left unpreserved for a long time will be spoilt by the activities of
microbes.
Pathogens enter the body through four main ways, namely: air, food and water, contact (direct
or indirect), and insect bites/cuts.

EVALUATION
1. Give two examples each of soil and sewage microorganisms
2. List four ways through which microorganisms enter the body

CARRIERS OF MICROORGANISM
Any agent that carries microbes from one place to another is called a carrier. Carriers can be
living or non-living things. Non-living carriers include air, water, and food while animals (e.g.
houseflies, mosquitoes, rats, cats, etc) are the living carriers. Animal vectors carry pathogens
either mechanically or biologically. In mechanical method, animals carry the pathogens on their
bodies where they cannot grow or multiply. In biological method, the vector becomes infected by
feeding on the body fluid of infected persons or animals.

Vector or Carrier Micro-organisms Disease caused

(i) Anopheles (female) mosquito Plasmodium Malaria fever
(ii) Tse-tse fly Trypanosome Sleeping sickness
(iii) Housefly Vibro cholera Cholera and typhoid fever
(iv) Aedes mosquito Virus Yellow fever

EVALUATION
1. What are vectors
2. Mention two ways by which animal vectors carry pathogens.
3. Explain each of the method described above

GENERAL EVALUATION
1. Give two examples each of the following microorganisms (i) fungi (ii) Bacteria (iii)
Algae (iv) Protozoa
2. What do you understand by the word ‘agar’
3. Describe ways by which microorganisms can be transmitted
4. State the vectors and the diseases caused by the following organisms (i)
plasmodium (ii) trypanosome (iii) vibro-cholerea
READING ASSIGNMENT:College Biology, chapter 21, page 465 – 484

WEEKEND ASSIGNMENT
1. When bacteria are arranged in chains, they are called (a) spirilla(b) staphylococci (c)
streptococci (d) bacilli
 2. Viruses are considered to be living organisms because they (a) possess transmittable
characters (b) move from one place to another (c) respond to stimulation (d)
ingest food materials
3. Which of the following is not a protozoan? (a) paramecium (b) plasmodium (c)
penicillium (d) Amoeba
4. Which of the following best describes a culture solution? (a) A population of micro-
organisms cultivated in a medium (b) A population of weeds cultivated in a
medium (c) Solution containing different chemicals (d) Solution containing dead
organisms
5. Which of the following organisms is not a fungus? (a) Rhizopus (b) Plasmodium (c)
Mucor (d) Aspergillus

THEORY
1. Differentiate between pathogens and vectors
2. Describe the structure of a virus
 WEEK SIX DATE: ……………………………

MICRO-ORGANISMS IN ACTION

CONTENT
 Growth of Microorganisms
 Beneficial and Harmful Effects of Microorganisms
 Diseases Caused by Microorganisms, Symptoms, Mode of Transmission and Control

GROWTH OF MICRO-ORGANISMS
Bacteria reproduce by binary fission in which a single cell divides into two. This process is
called asexual reproduction. The time interval required for the cell to divide into two is called
generation time. This time varies from one organism to another. It strongly depends upon
nutrient availability, temperature, gaseous requirement and pH. There are different phases in the
growth of bacteria. These include the (i) lag phase (ii) logarithmic or exponential phase (iii) the
stationary phase and (iv) decline or death. The growth of micro-organisms can be measured by
using any of these methods:
a. Turbidity method.
b. Serial dilution method.
c. Squared transparent paper or cellophane method.

EVALUATION
1. State four factors that can affect the growth of microorganisms.
2. List three ways of measuring the growth of bacteria.

BENEFICIAL AND HARMFUL EFFECTS OF MICRO-ORGANISMS

BENEFICIAL EFFECTS
1. Bacteria help to digest cellulose in herbivores.
2. In man, they synthesize vitamin K and B12
3. Bacteria and fungi are widely used in the synthesis of antibiotics
4. They are used to manufacture amino acids and vinegar
5. Bacteria are used to process milk into different tastes and flavours
6. They are used to decompose sewage into harmless inorganic compounds.
7. Microbial cultures are used to produce enzymes
8. Yeast is used as a leavening agent in baking industries.
9. Algae play important role in fertilizing the soil.
10. Bacteria are used to produce single-cells protein (SCP).
HARMFUL EFFECTS
1. Bacteria cause decay and spoilage of food items.
 2. Materials like wood, paper, textiles, rubber and metals are destroyed by microbes.
3. They cause diseases of different types.

EVALUATION
1. State thee beneficial and three harmful effects of microorganisms.
2. Mention five mention five beneficial and five harmful microorganisms.

DISEASES CAUSED BY MICRO-ORGANISMS

DISEASE CAUSATIVE AGENT SYMPTOMS TRANSMISSI CONTRO

ON L
Chickenpo Varicella Virus Fever, tiredness, and Contact Isolate
x an itchy, blistery patient and
rash. use
appropriat
e drugs.
Cholera Vibrio Cholerae  Watery diarrhea, flies, food , Personal
vomiting, leg faeces, hygiene.
cramps. carriers

Common Rhino Virus Cough, runny nose, Contact Take

Cold shivering, etc. appropriat
e
medication
s and
avoid
contact.
Dengue Dengue Virus Aedes Mosquito Drain the
(arbovirus) Severe headache, water and
severe eye pain clear the
(behind eyes), joint bushes
pain, muscle and/or around.
bone pain, rash, mild
bleeding (e.g., nose
or gum bleed,
petechiae, or easy
bruising),low white
cell count.
Diarrhoea Giardia intestinalis Frequent passing of contaminated Personal
watery faeces, stools hygiene
cramps and pains in
the abdomen
(stomach), nausea
and vomiting.
Diphtheria Corynebacteriumdipthe A sore throat, Contact Use
riae (Bacteria) hoarseness, painful antibiotics
swallowing, swollen and avoid
glands (enlarged contacts.
lymph nodes) in your
neck, thick,
difficulty breathing
or rapid breathing,
nasal discharge,
fever and chills, &
malaise.
Leprosy Mycobacterium leprae Disfiguring skin Long and close Use
sores, lumps, or contact antibiotics
bumps (that do not and avoid
go away after several contacts.
weeks or months), Patients
loss of feeling in the should be
arms and legs, isolated.
muscle weakness.
Measles Measles virus A high temperature, Contact Take
(ParaMyxoVirus) sore eyes appropriat
(conjunctivitis), e
runny nose, small medication
white spots, harsh and avoid
dry cough, going off contact.
food, tiredness,
aches, pains,
diarrhoea and/or
vomiting.
Pneumonia Diplococcus pneumonia High fever, shaking bacteria Use of
chills, cough with transmission by antibiotics
phlegm (a slimy contact. and
substance) which avoidance
doesn't improve or of contact.
worsens, shortness of
breath, chest pain
when you breathe or
cough, suddenly
feeling worse after a
cold, etc.
Poliomyelit Polio Virus or Fever, sore throat, houseflies, food Good
is Enterovirus headache, vomiting, and hygiene
fatigue, back pain or water and
 stiffness, neck pain appropriat
or stiffness, pain or e
stiffness in the arms medication
or legs, muscle .
weakness or
tenderness, &
meningitis.
Rabies Rhabdovirus Fever, cough, sore mad dog bites Treat dogs
throat, etc. and seek
urgent
medical
attention
in cases of
bites.
Septic Sore Streptococcus Bacteria Fever, nasal Contact Use of
Throat drainage, sore antibiotics
throat, swollen and
glands, difficulty avoidance
swallowing, and of contact.
irritability.
Sleeping TryponosomaBrucei  Anxiety, drowsiness reaches lymph Clear
Sickness during the day, fever, nodes via vegetation
headache, transmission s around,
thru fly bites use
 insomnia at night, insecticide
mood changes, s and take
sleepiness, appropriat
 sweating, swollen e
lymph nodes all over medication
the body, .
 swollen, red, painful
nodule at site of fly
bite.
Smallpox Variola Virus High fever, Contact Take
vomiting, fatigue, appropriat
backache, a raised e
spotted rash, etc. medication
and avoid
contact.
Tuberculos Mycobacterium Malaise, weight loss, Bacteria Isolate
is tuberculosis and night sweats. transmission by patients
cough and use
appropriat
e
antibiotics.
Tetanus Clostridium tetani Muscle spasms and bacteria in soil Treat
breathing problems. thru wounds
wounds urgently.
Typhoid Salmonella Typhi  Abdominal Flies, food etc. Treat
tenderness, water
before
 agitation, bloody drinking.
stools, Maintain
chills,confusion, personal
difficulty paying hygiene.
attention, fluctuating Use
mood,nosebleeds,sev appropriat
ere fatigue,weakness, e
etc. antibiotics.
Whooping Hameophilius Pertussis Cough, whooping coughing and Isolate
cough sound during sneezing patients
breathing, etc. and use
appropriat
e
antibiotics.
Influenza Orthomixovirus fever and muscle Contact Take
Flu aches, cold, runny appropriat
nose, sore throat, etc. e
medication
and avoid
contact.
Malaria Plasmodium chills, Bite from female Use of
headache,muscle Anophelex drugs,
aches, tiredness, mosquitoes insecticide
nausea, vomiting and s, etc.
diarrhea.
EVALUATION
1. State the causative organisms, symptoms and control of the following
diseases (i) Malaria (ii) Cholera (iii) Tuberculosis (iv) Measles (v)
Poliomyelities
2. List five airborne and waterborne microorganisms respectively.

GENERAL EVALUATION
1. Mention the observable phases in the growth of microbes.
2. State five uses of microorganisms in industries.
3. Outline four general ways of controlling microorganisms.
4. Mention three microorganisms each that are involved in Nitrogen and Carbon cycle.
5. State three uses of microorganisms in (i) Agriculture (i) Medicine
6. Describe three ways of measuring growth of bacteria.
 7. List five ways through which microorganisms can be transmitted.
READING ASSIGNMENT: College Biology, chapter 21, page 467 - 484.

WEEKEND ASSSIGNMENT
1. The growth phase in bacteria in which cells divide steadily at a constant rate is
called (a) Exponential phase (b) lag phase (c) stationary phase (d) decline
phase
2. Which of the following microbes causes cholera? (a) Virus (b)Bacterium (c)
Protozoan (d) Fungus
3. Growth of micro-organisms can be measured by the following methods
except___________ method (a) serial dilution (b) turbidity (c) squared transparent
paper (d) dry weight
4. The following practices contribute to the control of the spread of diseases except (a)
sewage treatment with chemicals (b) proper sewage disposal (c) disinfecting the
surrounding (d) using human faeces as manure
5. The vector of the trypanosome parasite is (a) housefly (b) tse-tse fly (c)
mosquito (d) black fly
THEORY
1. Define the following phases in microorganisms growth (i) lag (ii) exponential (iii)
stationary.
2. State four ways in which each of the following organisms are beneficial to
humans. i. Bacteria ii. Fungi
 WEEK SEVEN DATE ……………………………….

SEXUALLY TRANSMITTED INFECTIONS

CONTENT
 Definition, Mode of Transmission, Symptoms, Prevention and Control
 HIV and AIDS

Sexually Transmitted Infections (STIs) (veneral diseases) are the diseases that are contacted
through sexual intercourse. Examples include syphilis, gonorrhea, herpes, thrush, AIDSetc.The
table below shows a list of STIs, their symptoms, transmission, etc.

DISEASE CAUSATIVE SYMPTOMS PREVENTION/CONTROL

ORGANISM

GONORRHOEA Bacterium (Neisseria  Burning  Discourage

gonorrhea) sensation commercialized
during prostitution
urination in  Avoid multiple sexual
males partners
 A thick  Get medical attention and
yellowish stop sexual intercourse
discharge in with previous partner(s)
males
 Pain on
passing urine
in females
 Vagina
discharge
and swelling
of the vulva
 Redness
around the
urinary
openings
 Sterility at
advanced
stage

SYPHILIS Bacterium  A small As in gonorrhoea

(Treponemapallidium) painless sore
appear on the
penis or
vulva at the
initial stage
  Fever, skin
rashes,
mouth ulcer,
aching pains
at the lymph
node regions
at secondary
stage
 Nervous
disorder,
insanity,
repeated
abortion
etc.

Acquired Human immune –  Fever,  Keep one faithful partner

immunue deficiency virus (HIV) chronic  Avoid sharing sharp
deficiency diarrhea objects such as razor
syndrome  Excessive blade,
(AIDS) weight loss  Screening of blood before
 General skin transfusion
irritation  Avoid oral, anal sex and
 Swelling of kissing
the glands  National mass campaign
 Persistent to educate people on the
cough danger of HIV
 Persistent
severe
fatigued

Genital warts Human  Painless,  Vaccine available for

papillomavirus (HPV) flesh women aged 9 -26.
coloured  sharing personal items,
bumps/warts including towels, razors,
develop on bars of soap, footwear, or
the penis, in other objects
and around
the vagina
and the anus
and may re-
appear at
different
times.
 Cervical
cancer
HIV AND AIDS
HIV (Acquired immune deficiency virus) is the pathogen that caused AIDS, a sexually
transmitted disease. AIDS is a disease in which the immune system of the human body is
completely broken down, rendering the body unable to fight against any pathogens that attack
it.HIV belong to a group of RNA virus referred to as retro – viruses. They are capable of
converting their RNA to DNA; they attack, infect and destroy certain white blood cells called
helper T cells or CD4 (lymphocytes).
HIV can remain dormant in the cell of the host for years and multiplying as the cells of the host
divide, eventually the virus becomes active producing many viruses causing the killing of the
helper T cells. Once the body looses too many helper T cells, the body’s defense against
infections crumbles and the body becomes vulnerable to various disease pathogens causing
various opportunistic diseases.
MODE OF TRANSMISSION
Apart from sexual intercourse, HIV can be transmitted through
a. Receiving blood transfusion from an infected person
b. Infection through pregnancy, child birth and breast feeding
c. Using unsterilized infected needles and syringes
d. By practicing oral and anal sex
e. Open mouth kiss with an infected person

EVALUATION
1. Mention five sexually transmitted diseases
2. State the causative organisms of the diseases mentioned above.

GENERALEVALUATION/REVISIONAL QUESTIONS
1. Mention five beneficial and five harmful effects of microorganisms.
2. In a tabular form, state causal agent and symptoms of five bacterial diseases.
3. State three airborne diseases and their symptoms.
4. What are sexually transmitted infections?
5. State five STIs, their causal agent, mode of transmission and symptoms.
READING ASSIGNMENT: College Biology, chapter 21, page 469 - 472

WEEKEND ASSSIGNMENT
1. The following diseases are caused by bacteria except (a) gonorrhea (b) AIDS (c)
syphilis (d) none of the above
2. A disease characterized by high fevers, loss of weight, chronic diarrhea, wasting away
and final death is (a) gonorrhoea (b) AIDS (c) syphilis (d) none of the above
3. Which of the following is not a sexually transmitted disease? (a)
gonorrhea (b) malaria (c) syphilis (d) AIDS
 4. Which of the following statements is wrong? (a) All STIs are caused by viruses (b)
All STIs are caused by bacteria (c) All STIs are caused by protozoans (d) All of the
above
5. A disease which displays symptoms which are similar to the symptoms of other diseases
is (a) syphilis (b) malaria (c) river blindness (d) none of the above

THEORY
1. State the causative organisms, five modes of infection and five ways of controlling AIDS.
2. Differentiate between HIV and AIDS.
3. Differentiate between passive immunity and active immunity.
WEEK EIGHT DATE …………………………

TOWARDS BETTER HEALTH

CONTENT
 Control of HarmfulMicroorganisms.
 Definition and Ways of ControllingVectors.
 Maintenance of GoodHealth.
 Roles of HealthOrganizations.

CONTROL OF HARMFUL MICRO-ORGANISMS

The control of harmful microbes include removal, inhibition of growth or killing by physical
agents/processes and chemical agents or antibiotics. Some common methods of controlling
harmful microorganisms in order to maintain good health include
1. High and low temperature: Boiling or heating of food, pasteurization of milk,
sterilization of medical instruments and freezing of food to reduce the activities of
microbes to barest minimum.
2. Covering of food to prevent vectors and pathogens in the air from coming in contact
with the food.
3. Antibiotics such as amphiclox, ampicillin, penicillin, tetraclycline, are drugs used to kill
many bacteria causing diseases.
4. Antiseptic such as dettol, Milton, chlorine water, medicated soap and hydrogen peroxide
destroy micro-organisms while others prevent the multiplication of the micro-organisms.
5. Disinfectants are stronger antiseptic. Examples are sanitas, Lysol and izal. They are used
to disinfect hospitals warehouses and public buildings. Antiseptics and disinfectant have
to be diluted to render them gentle or mild to the skin
6. High salinity (salting): Salt is used to preserve food. When salt is applied to food items
like fresh meat or fish, the micro-organisms are destroyed. The bacterial cells are
plasmolysed due to the movement of water from the cells of the bacteria.
7. Dehydration: When foodstuffs such as fish and meat are dried, micro-organisms cannot
thrive on them. Bacteria need water to survive. So dehydration prevents the survival of
micro-organisms.
8. Sanitation: Keeping the body and the environment clean.
9. Isolation of infected persons: Persons suffering from infectious diseases such as
tuberculosis and cholera must be isolated so as to prevent the spread of such diseases to
other members of the community.
10. Balanced diet: Eating balanced diet everyday helps to promote good health and high
body resistance to diseases.

EVALUATION
1. Describe five ways of controlling harmful microorganisms.
2. What method is most effective in microbial control.
VECTORS AND WAYS OF CONTROLLING VECTORS
A vector is an animal which transmits disease-causing organisms (pathogens) from the victim of
that disease to another person.

Control of mosquitoes
 Draining of swamps
 Clearing of bushes around houses
 Sleeping in a room protected by mosquito net.
 Spray swamps or rooms with insecticides.
 Spray oil on stagnant water.
 Using insect repellant on body.
 Use of drugs
 Burying broken pots and cans.

Control of Houseflies
 Spraying with insecticides
 Destruction of breeding spots
 Use of poison baits
 Closing of pit toilets
 Covering of food
 Keeping environment clean.

EVALUATION
1. List four ways each of controlling black fly, tse-tse fly and rodents
2. Explain other ways mosquitoes can be control.

MAINTAINANCE OF GOOD HEALTH

There are many ways of maintaining good health. These include:
a. Refuse disposal: Refuse are solid waste materials discharged through human activities
from homes and industries into the environment. Reckless refuse dump around dwelling places
creates bad odour, provides breeding grounds for insects and rodents that spread diseases. Refuse
disposal can be done through the following ways; Provision of dust bins in strategic locations,
Burning of refuse in incinerators, Dumping them in isolated areas far from human habitation,
Burying refuse in sanitary landfill.
b. Sewage disposal: Sewage are waste water materials discharged from laundries, kitchen,
toilets, bathrooms e.g. urine and faeces. Sewage disposal is done through the use of pit toilets
where faeces and urine are passed into deep pits,the use of septic tanks where water is used to
flush faeces and urine into a big tank dug in the ground, community treatment process where
sewage from various homes are collected and treated before being discharged into the oceans or
rivers.
c. Protection of water: In view of various diseases which man contact because of drinking
unclean water, water should be protected through the following ways: addition of alum to water,
boiling of water before drinking, filtration of water on cooling, addition of chlorine to kill
microscopic germs,storage of water in clean containers.
d. Protection of food: The following methods of food protection are recommended: Keep
food in refrigerators or deep freezers, boil or cook raw food properly before eating, there should
be inspection of food meant for public consumption, washing of hands before and after eating of
food, food should be preserved through canning, keep the environment where the food is
prepared clean, avoid exposure of food to flies and other micro-organism.
EVALUATION
1. State four ways of purification of water
2. Differentiate between refuse and sewage

ROLES OF HEALTH ORGANIZATIONS

The administration of health services in Nigeria is achieved through the following approved
organizations:
a. Ministry of Health
b. University Teaching Hospitals
Countries cooperate to tackle health issues. At international level, health control is organized top
prevent the spread of diseases and also to provide aid to needy areas. This can be in the form of
drugs, medical equipments, money, etc.
International Health Organizations include: World Health Organization (WHO), United Nations
Children’s Fund (UNICEF), International Red Cross (IRC), United Nations Educational,
Scientific and Cultural Organization (UNESCO).

World Health Organization (WHO)

This is the world’s principal agency for dealing with health and nutritional problems. It was
established in 1964 and became operational in 1948. The functions of WHO are as follows:
i. It provides and assists national governments at their request to strengthen their health
services.
ii. It promotes and provides improved methods of training health, medical related
professional experts for member countries.
iii. It promotes cooperation among scientific and professional bodies for the improvement of
health.
iv. It cooperates with other organizations in the improvement of nutrition, sanitation,
housing working conditions and other matters that relate to health.
v. It helps and promotes material and children’s health care and welfare.
vi. It produces medical publications.
vii. It provides drugs and vaccines in cases of emergency

United Nations Children’s Fund (UNICEF)

This is a body set up by the U.N. It performs the following functions:
 i. It provides emergency needs for children in areas affected by diseases or famine.
ii. It improves the nutritional condition of undernourished children.
iii. It feeds and cares for disabled children.
iv. It undertakes immunization programmes for children’s diseases like measles, whooping
cough, etc.
v. It ensures the provision of clothing and other needs for children

International Red Cross

This is a humanitarian organization whose functions are to serve humanity during peace and war
times. During war, it performs the following functions:
i. Care for the injured.
ii. Provision of emergency aid.
iii. Negotiating for the exchange of the prisoners of war.
iv. Evacuation of refugees.
v. Welfare of war prisoners.

United Nations Educational, Scientific and Cultural Organization (UNESCO)

Although, this is not directly a health organization, it assists health services indirectly by raising
the educational standards of the people in developing countries.

EVALUATION
1. List three Health organization and outline four roles of each.
2. Write short note on the life cycle of plasmodium.

GENERAL EVALUATION
1. State five roles of UNICEF as a health organization
2. State five roles of World Health Organization
3. What is pasteurization?
4. What is quarantine?
5. Outline four general methods of controlling vectors
READING ASSIGNMENT: College Biology, chapter 22, page 485 - 495.

WEEKEND ASSSIGNMENT
1. A way of providing good health in a community is (a) control of diseases (b) sewage
disposal (c) refuse disposal (d) all of the above
2. Which of these is not a vector? (a) Black fly (b) Snake (c) Dog (d) Housefly
3. The process of heating liquid food at a controlled temperature thereby enhancing its
quality and destroying harmful micro-organisms (a) Pasteurization (b) Boiling (c)
Frying (d) None of the above
4. An agent that stops the growth of fungi is called (a) fungistat (b)
fungicide (c) germicide (d) none of the above
 5. The process by which water is removed from bacteria cells which leads to the cell been
plasmolysed is referred to as (a) drying (b) salting (c) dehydration (d)
pasteurization

THEORY
1. Name the causative organism and vector of Malaria
2. List five symptoms of Malaria
3. Mention five ways by which mosquito can be control and state the reason for each
method
 WEEK NINE DATE …………………………………
RELEVANCE OF BIOLOGY TO AGRICULTURE
CONTENT
 Classification of plants
 Botanical classification
 Agricultural Classification
 Classification based on life cycle
 Classification based on size
 Effects of agricultural practices on ecological systems

CLASSIFICATION OF PLANTS
Plants exists in various forms and types hence, the need for classification. Plants can be classified
on the following bases
i. Botanical classification
ii. Agricultural classification
iii. Classification based on life cycle
iv. Classification based on size

BOTANICAL CLASSIFICATION
The concept of binomial nomenclature has it that plant kingdom can be subdivided into divisions,
classes, orders, families, general and species. This is based on their structures, functions and
evolutionary trends. Plants are then generally classified into three brand groups
i. Thallophytes (A)
ii. Bryophytes (B)
iii. Tracheophytes (C)
Tracheophytes are further grouped into pteridophytes (D) and spermatophytes (E). The
Spermatophytes can also be grouped into gymnosperms (F) and angiosperms (G). The
angiosperms are subdivided into dicot (H) and Monocot (I)

Plants B D F H

C E
G I
 BOTANICAL CLASSIFICATION CHARTS
A & B are non- vascular plants, C refers to vascular plants. D refers to non-flowering plants; E
refers to seed plants while G refers to flowering plants proper.

EVALUATION
1. Outline the criteria (bases) for classifying plants
2. List the three factors upon which botanical classification is based

AGRICULTURAL CLASSIFICATION
Agricultural classification of plants is based on:.
i. The product obtained from the plants
ii. The parts of the plant that is useful
iii. The economic importance of the plants
Plants are therefore classified agriculturally into the following
1. CROPS AND WEEDS: - plants that are needed on the farm are called crops while other
unwanted are called weeds.
2. FOOD CROPS AND CASH CROPS: - crops grown mainly for human consumption are
called food crops e.g. maize, yam etc. Those grown mainly to earn money are cash crops
e.g. cocoa, coffee
3. ROOT CROPS: - are plants which store mainly starch in edible underground stems or
roots e.g. yam, cassava etc.
4. CEREAL CROPS: - these are monocotyledonous plants of grass family, whose grains are
eaten e.g. maize, millet, guinea corn, rice, wheat, etc. They are rich in carbohydrates.
5. FRUITS CROPS:- are rich in vitamins and minerals. Fruits are also rich in sugar. These
include oranges, mangoes, avocado peers, cashew etc. whose fruits are eaten
6. VEGETABLE CROPS: - are herbaceous plants whose vegetable (leafy) parts are
eaten. They include spinach, lettuce, carrots, cabbage, okro, tomato, onion, pepper
etc. They are also rich in vitamins and minerals.
7. LEGUMES: - are plants of beans family such as cowpea and groundnuts whose seeds are
eaten. They are rich in proteins
8. SPICES: Are plants whose parts are used for seasoning food such as pepper, curry, thyme
and ginger.
9. LATEX PLANTS: Are plants that are grown for their useful latex (a milky fluid) e.g.
rubber plants used for making natural rubber in the tropical countries
10. FIBRE PLANTS: Are plants which produce fibre for the purpose of rope making, textile
and bags production e.g. cotton, hemp etc.
11. BEVERAGE AND DRUG PLANTS: - Are plants whose parts are taken as stimulants or
drugs e.g. tea, coffee, cocoa and kola nut, quinine tree for medicine.
 12. OIL PLANT: - Produce oil of economic value e.g. oil palm, sheanut, groundnut, coconut,
castor oil plant and melon.
EVALUATION:
1. What are the factors considered in agricultural classification of plants?
2. Differentiate between fruits crops and vegetable crops

PLANT CLASSIFICATION BASED ON LIFE CYCLE AND SIZE

Based on life cycle (period or existence) plant can be classified as
a. ANNUALS: - These are plants which complete their life cycle within one growing season
or within a year e.g. Maize, Yam, Melon, cowpea, tomato etc.
b. BIENIALS: - These complete their life cycle within two years e.g. Banana, plantain,
pineapple etc.
c. PERENNIALS: - These persist over (more than) two years producing their yields every
season e.g. orange, mango, oil palm cocoa etc.
Plant based on size fall into three categories
1. Herbs are small plants with fleshy stem e.g. Spinach, waterleaf etc.
2. Shrubs are medium – sized plants with woody stem branch very close to the ground (soil)
e.g. hibiscus
3. Trees are big plants with woody trunk, which branch at the top e.g. Iroko, Mahogany,
Cashew, and Coffee etc.

EVALUATION
1. Classify the following plants based on their life cycle (a) Vegetable (b) Pineapple (c)
almond tree
2. Give two examples each of herbs, shrubs and tree crops

EFFECTS OF AGRICULTURAL ACTIVITIES ON ECOLOGICAL SYSTEM

The following agricultural or farming practices carried out by farmers have some consequences
on the ecological system. These agricultural practices and their effects include;

a. Bush Burning: Bush burning involves the setting of fire in the bush to clear out the
vegetation.Effects of bush burning include
 Destruction of the organic matter in the soil
 Atmosphere is polluted with smoke.
 Many of the micro-organisms are killed
 exposes the soil to erosion and leaching
 reduces the water holding capacity of the soil
 Bush burning leads to the extinction of some animals
  The ash produced by bush burning gives the soil a slightly alkaline nature
b. Overgrazing: Overgrazing is a situation where more animals than what can be supported
on a particular pasture are put there to graze. It is a way of exceeding the carrying capacity
of the soil. Overgrazing
 removes the vegetative cover of the soil
 exposes the soil to erosion
 destroys the soil structure
 More faeces are dropped on the soil which could improve the fertility of the soil.
 Weeds can eradicated from such lands
 It leads to compactness of the soil resulting from continuous trampling of animals.
 causes poor growth and regenerative capacity of vegetation
c. Tillage: Tillage is defined as the working, digging or breaking up of the soil in preparation
for the planting of crops. Tillage encourages leaching
 helps to loosen the soil
 it enhances proper aeration of the soil
 tillage exposes the soil organisms and may kill some
 it changes the structure and texture of the soil
 tillage leads to changes in the ecology of the land
 Intensive tillage can lead to loss of soil fertility.
 It exposes the soil to erosion.
d. Deforestation: Deforestation is the continuous removal of forest stand (trees) either by
bush burning or indiscriminate felling without replacing them. Deforestation
 It reduces water percolation due to absence of humus and dead leaves on the soil
 It reduces the amount of rainfall in the area
 Deforestation hinders micro-organisms activities in the soil
 It results in loss of nutrients through leaching and erosion
 It reduces wildlife population in the area concerned
 It reduces the humus content of the soil
e. Fertilizer application: This involves the application of certain chemicals or substances
into the soil to improve its fertility. Effects of fertilizer application include
 It brings about the loss of organic matter or humus
 It deteriorates the structure of the soil
 Fertilizer increases the porosity of the soil
 It supplements nutrient content of the soil
 Excessive application of fertilizer can cause soil acidity
 The productive capacity of the soil is enhanced by the application of fertilizer
 It stimulates vegetative growth, hence it reduces soil erosion
f. Application of pesticides/herbicides: Pesticides are chemical substances which are used
to destroy or kill pests while herbicides are also chemical substances in form of solution or
gases capable of destroying weeds. Effects of pesticides application include
 It causes pollution of the environment.
 It affects or destroys other useful plants and animals.
 It reduces the population of the target insects or plants.
 Pesticides may leave undesirable residue in the environment.
 When such chemicals are washed into rivers or lakes, they can cause death of
aquatic animals.
EVALUATION
1. State three effects of fertilizer application, tillage and bush burning on the ecosystem.
2. Explain with reason the most ecologically friendly agricultural practice.

GENERAL EVALUATION
1. Based on size, classify water leaf, hibiscus and oil palm
2. Differentiate between shrubs and trees
3. Discuss the botanical classification (using example where appropriate)
4. In what ways are fruits and vegetable crops similar
5. Differentiate between root and cereals crops
6. Differentiate between annual and perennial crops giving two examples each.

WEEKEND ASSIGNMENT
1. Which of the following is not an example of classification of plants (a) Herbs and
shrubs (b) annual and perennials (c) Graminae and enphorbinosae (d) monocot and
dicot
2. Plants can be classified based on all these except (a) botanical (b) size (c) agricultural
use (d) planting season
3. Fruits crops are rich in (a) Vitamin and Minerals (b) Vitamins and protein (c) Mineral and
carbohydrate (d) protein and carbohydrate
4. Spices include (a) Pepper and ginger (b) Palm oil and ginger (c) Lettuce and carrot (d)
yam and maize
5. Which of these does not have negative effect on the ecological system (a) fertilizer
application (b) crop rotation (c) tillage (d) bush burning

THEORY
1. State three effects each of the following farm practices on the ecosystem
i. Bush clearing
ii. Shifting cultivation
iii. monocropping
What are the classes of plants based on uses.