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Biology Lesson Note for SS2 (Second Term) 2023

Biology lesson note for SS2 Second Term is now available for free. The State and Federal Ministry of Education has recommended unified lesson notes for all secondary schools in Nigeria, in other words, all private secondary schools in Nigeria must operate with the same lesson notes based on the scheme of work for Biology.

Biology lesson note for SS2  Second Term has been provided in detail here on

Biology Lesson Note for SS2 (Second Term) [year] 1


For prospective school owners, teachers, and assistant teachers, Biology lesson note is defined as a guideline that defines the contents and structure of Biology as a subject offered at SS level. The lesson note for Biology for SS stage maps out in clear terms, how the topics and subtopics for a particular subject, group works and practical, discussions and assessment strategies, tests, and homework ought to be structured in order to fit in perfectly, the approved academic activities for the session.

To further emphasize the importance of this document, the curriculum for Biology spells out the complete guide on all academic subjects in theory and practical. It is used to ensure that the learning purposes, aims, and objectives of the subject meant for that class are successfully achieved.

Biology Lesson note for SS2 carries the same aims and objectives but might be portrayed differently based on how it is written or based on how you structure your lesson note. Check how to write lesson notes as this would help make yours unique.

The SS2 Biology lesson note provided here is in line with the current scheme of work hence, would go a long way in not just helping the teachers in carefully breaking down the subject, topics, and subtopics but also, devising more practical ways of achieving the aim and objective of the subject.

The sudden increase in the search for SS2 Biology lesson note for Second Term is expected because every term, tutors are in need of a robust lesson note that carries all topics in the curriculum as this would go a long way in preparing students for the West African Secondary Examination.

This post is quite a lengthy one as it provides in full detail, the Biology-approved lesson note for all topics and sub-topics in Biology as a subject offered in SS2.

Please note that Biology lesson note for SS2 provided here for Second Term is approved by the Ministry of Education based on the scheme of work.

I made it free for tutors, parents, guardians, and students who want to read ahead of what is being taught in class.

SS2 Biology Lesson Note (Second Term) 2023











CLASS: SS2                                                                                          


(a) Types of associations

(b) Features of biological importance possessed by organism of an association



Ecology is defined as the study of living organisms and the relationships or interactions between them and their environment. The interactions between plants and animals in their environment are usually described as biotic interactions or associations. There is a close association between the biotic and abiotic components of the environment. Both affect each other and are equally important for the ecosystem.


Symbiosis is a term for all associations in which all or some of the species involved benefits or loses. It is interdependence of different species, which are sometimes called symbionts. Based upon the specific relationship between the species involved in a symbiotic association, at least one member benefits. There are three main types of symbiosis

Symbiotic relationships may be grouped as:

  1. Parasitism
  2. Mutualism
  3. commensalism

Lichens of the Splash Zone of the Intertidal Region

Lichens are actually a combination of two entirely different types of living organisms, an alga and a fungus. This association is called a symbiotic relationship. In this particular type of symbiotic relationship neither partner can live independent of the other. Lichens are very slow growing and can survive very harsh environmental conditions and are ecologically significant in that they contribute to the weathering of solid rock.



It is a type of antagonistic association occurring between two species, in which a specie called the parasite, is gaining at the expense of the other – the host, which is losing. Parasitism is a mode of life. The benefits the parasite derives from a host may include food, oxygen, living space and support. The host is usually much bigger than the parasite. Parasitism does not usually lead to the death of the host. It can however lead to a number or harms such as reduction in growth, predisposition of the host to attack by diseases and weakening.


Life Cycle of Human Blood Flukes

Flukes of the genus Schistosoma parasitize two hosts. The young hatch from their eggs in rivers and lakes and enter a specific kind of aquatic snail, where they develop into tadpole-like larvae called cercariae. When the cercariae leave the snail, they burrow through the skin of a human host swimming or wading in infested water. Adult flukes mature in the host’s bloodstream and settle in the veins of the gut. Their eggs, deposited in the lining of the human intestine and bladder, pass back into water via the sewage system, and the cycle begins again. More than 200 million people worldwide suffer from schistosomiasis, a disease characterized by the abscesses and bleeding caused by the flukes’ infestation.


In parasitism, the parasite can be of varying types among which are the following:

  • Ectoparasite e parasite living in the outside of the host tissue e.g. tick, lice, (among animal parasites and dodder – a plant parasite.
  • Endpoparasitee. a parasite that lives in the inside of the host tissue, e.g. tapeworm, round worm, malaria parasite (plasmodium), bacteriophages which are viruses that attacks bacteria.


Examples of plant parasites are mistletoe and dodder (cuscuta) and many other fungal and bacterial parasites.


Examples of animal parasites include tapeworm, roundworm, plasmodium, lice, jigger and tick, bed bug.


Ebola Virus Infection

Much research remains to be carried out on the Ebola virus, a highly infectious and deadly virus that spreads through the use of unsterilized needles, through contact with an infected individual, or the corpse of someone who has died from the disease. About one week after infection, the virus begins attacking blood and liver cells (1). As the disease swiftly progresses, the virus may destroy vital organs such as the liver and kidneys (2), leading to massive internal bleeding (3). Shock and respiratory arrest soon follow, then death. Currently, there is no vaccine to prevent infection, and no drugs to halt the disease.



Mutualism is a type of association which is beneficial to all the species involved, none looses. It is a mode of life.


Common examples of mutualism include:

  1. Relationship between legumes and nitrogen.
  2. Fixing bacteria (rhizobium) in their root nodules of leguminous plants.
  • Association between termites and the protozoan inhabiting their gut.
  1. Lichens which is an association between algae and fungi.
  2. Mycorrhiza which is an association between plant roots and fungi




Commensalism is a type of association which one of the species involved benefits from the association and the other neither gains nor looses (i.e unharmed and unaffected).


Examples include:

  1. The association between trees and the epiphytesthat use their trunks as the subtraction for the anchorage of their roots.
  2. Another association between the shark and the small fish called Remorathat fasten their mouth near the mouth of shark which provides such fish with small bits of food that fall off from the mouth of the shark.

iii. Some bacteria live in the human large intestine. They feed on the food in the gut and do not harm the host.



  1. Define the following terms; (a) ecology (b) association (with respect to ecological management).
  2. List four types of association between organisms in an ecosystem with a relevant example of each.
  3. State the main different between mutualism and parasitism.
  4. Explain the term commensalism, giving one example.



Living organisms possess a number of different adaptations which enable them to survive in their environment.


Adaptive features found in parasites

  1. Possession of organs for piercing the host and sucking nutrients from the host.
  2. Possession of structures for attachment to the host such as claws or suckers.
  • Ability to secrete enzymes that could dissolve tissues, thus facilitating entry into host’s body.
  1. Ability to produce a large number of offspring to increase chances of survival.
  2. Protective body surface (cuticle) to withstand host’s digestive enzymes (for intestinal parasites).

NOTE: Diagram of adaptation of ectoparasites is found in Modern Biology for Senior Secondary School page 135, figure 7.1


  1. List three adaptive features of parasite that facilitate their mode of life.
  2. Give specific examples of the organisms and their adaptive structures.
  3. Define the term association with respect to ecological management.
  4. Explain the term, commensalism, give two examples
  5. State the difference between mutualism and commensalism.



  1. An ecological unit in which two or more species of organisms occur in close proximity is known as (a) adaptation (b) assimilation (c) association (d) protocooperation
  2. Which of the following is not a term used to describe the interactions between plants and animals in an environment? (a) association (b) symbiosis (c) adaptation (d) biotic interaction
  3. Parasite that posses boring organ for penetrating the host body are called (a) endoparasite (b) indoparasite (c) exoparasite (d) ectoparasite
  4. Which of the following is not an example of commensalism (a) epiphytes growing on stem of large plant (b) bacteria living in the large intestine of human (c) association between remora and shark (d) tape-worm living in the small intestine
  5. Which of the following is not a parasite of animal (a) tick (b) dodder (c) nematodes (d) flukes



Write short notes on the following

  1. Tolerance range.
  2. lower lethal temperature

iii. Upper lethal temperature

  1. Physiological stress.




CLAAS: SS2                                                                                         


(a) Concept of minimum and maximum range of tolerance.

(b) Geographic range graph illustrating maximum and minimum range of tolerance



Tolerance is the ability of an organism to withstand extreme variation in the environmental conditions. Living organisms posses the ability to withstand minor unfavourable changes in the factors (biotic and abiotic) or their environment which affect their survival. Biotic components interact with abiotic components such as temperature, rainfall, high light intensity, salinity and soil factor. The abiotic factors play a significant role in the distribution of living organisms. For example temperature can prevent a plant from growing and surviving in an environment. The limits within which organisms can withstand changes in the abiotic factors depend on what is prevalent such environment.



House Mouse

The ubiquitous house mouse, Mus musculus, had its origins in Eurasia. Its precise original distribution isn’t known, and the relationship between wild forms and commensals-mice that live in proximity to, and depend upon, people-is a matter of dispute among zoologists. Today there are few places on Earth to which the house mouse has not been inadvertently introduced by people, who are more or less tolerant of its presence. Although capable of building up to pest proportions, destroying crops in the field, and depleting or contaminating stores of grain, as happens periodically in the notorious mouse plagues of Australia, house mice in other places seem able to live with their human hosts without causing much damage. In this, they differ from their larger and generally more dangerous and destructive cousins, the commensal brown rats and black rats.


Concepts of minimum and maximum range of tolerance

Organisms have a minimum and maximum limit to which they can tolerate their environment which influence their survival or success in such environment. This range is known as their limit of tolerance. Most organisms cannot exist outside their limits of tolerance. They therefore escape from such environment once these limits are being exceed or risk dying in such environment.



Variation in Rooster Combs

The comb in domestic fowl, a naked, fleshy crest on the top of the heads of both adult male and female birds, is more developed in the male. The structure of the comb can be quite variable, ranging from a simple, single, erect or drooping, serrated appearance to more elaborate forms, depending on the variety of the domestic fowl.


The law of minimum tolerance was introduced in 1840 by Justice Liebig and the law states that “the growth of a plant will be limited by whichever requisite factor is most deficient in a local environment”.

This law was expanded in 1913 by V.E. Shelfore by applying it to animals and considered the fact that too much of anything could be as bad as too little of it. Hence, Shelford’s law of tolerance states “the distribution of species will be limited by the environmental factor for which the organism has the narrowest range of adaptability.

Since organism can only live within certain minimum and maximum limits for each abiotic factor, the range between the upper and lower limit is 0oC and the maximum limit is 42oC. Their tolerance range is 0 – 42oC.

Based on the law of tolerance, an organism may have a wide range of tolerance for one abiotic factor and a narrow range for another factor. An organism with a wide range of tolerance for all factors is likely to have a wide distribution.



The distribution of the world’s flightless birds, called ratites, is indicative of the shifting of continents in the earth’s distant past. Ratites evolved on a landmass called Gondwanaland, which broke apart to give rise to Africa, South America, and Australia. Following this separation, the ratites of each of these continents gradually evolved into one or more distinct species—the ostrich of Africa (shown here), the rhea of South America, and the cassowary and emu of Australia.

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DIAGRAM: Tolerance range, optimum range and population size (Modern biology by sarojimi, page 142 figure 7.4).


A species can only be found in areas that are within the minimum and maximum limits of its tolerance. These limits, therefore give the geographic range or distribution of a species. The branch of biology that deals with geographical distribution of animals and plants is known as biogeography.

Variations in abiotic factors are responsible for the major biomes such as tropical rain forest, grassland (savanna), desert, freshwater and marine biomes. These have diverse species of plants and animals, which occur in micro habitats that support it within the overall range.

An organism’s ecological niche is the dwelling place as well as its activities, requirements and effects on the environment.



  1. State the law of tolerance.
  2. Explain the term ‘tolerance range’.
  3. Define tolerance and list five abiotic factors that determines. The survival of an organism in an environment.



  1. The ability of an organism to withstand extreme variations in the environmental condition is known as — (a) resistance (b) tolerance(c) adaptation (d) toughness.
  2. Which of the following is the tolerance range for most animals? (a) 0o-100oC (b) -5-35oC (c) 0o-42oC (d) 0o-45oC
  3. Law of minimum tolerance was introduced by (a) Carl shoe (b) Gregor Mendel (c) Justice Liebig (d) V.E. Shelford
  4. Which of the following is incorrect (a) a species can only found in area having its range of tolerance (b) variation in abiotic factors are responsible for distribution of a species (c) an ecological niche is also known as biomes (d) the ability of an organism to withstand extreme variation in environment is tolerance.
  5. “The distribution of species will be limited by the environmental factors for which the organism has the narrowest range of adaptability” is 9a) Max Shoe (b) Justice Liebig (c) V.E. Shelford (d) Carl Shoe




Read Modern Biology for SSS by Sarojini, Pages 141-142 and:

  1.  Define adaptation
  2. State five adaptive features of terrestrial organisms





Adaptation refers to any feature or characteristics possessed by an organism that contributes to its fitness and survival in its environment. In order to survive and fit into their environment, living organisms usually possess some adaptive features that make them to withstand life-threatening and unfavourable environmental conditions and promote their well-being and proliferation.

Adaptations are inherited characteristics of organisms. They are display in three main features of organisms, their physiology and their behaviour. Some insects mimic leaves in order to escape predators, while some plants produce toxins, which prevent other plants from growing near them, thus reducing competition.



The stem of a plant provides pathways for the distribution of water and nutrients between the roots, leaves, and other parts of the plant. The herbaceous stem of the dandelion (top, center) lacks lignin, the stiffening material in rigid, supportive woody stems. For this reason, herbaceous plants are generally limited in their physical size. Spurges and cacti (bottom, left), their leaves reduced to needles to prevent evaporation in a dry climate, consist entirely of stem material. Tubers, such as potatoes (top, right), are swollen, food-storing, underground stems that nourish growing buds. The stems of some plants are adapted for protection, as in the hawthorn (bottom, right). Others actively compete for sunlight, using touch-sensitive, curling tendrils (top, left) or other structures to climb upwards.



Plants are grouped into three on the basis of the environmental conditions under which they grow, especially on availability of water in the soil. The three groups are hydrophytes, mesophytes and xerophytes.


Adaptation of Hydrophytes

Hydrophytes are plants that have adapted to living in the aquatic environment. They are either submerged of floating on the water surface. The plants can also grow in the soil that is permanently saturated with water. Their adaptive features include the following:

  1. Possession of large air cavities called parenchyma that serve as a means of buoyancy and storing gases for respiration.
  2. Possession of photosynthetic chloroplast that make use of less light in water for photosynthesis.
  • Possession of breathing roots (pneumatophores) by some of the hydrophytes, which grows above the water level to get enough oxygen for respiration.
  1. Possession of hairy leaves and thin and waxy cuticle to repel rain water as they do not meet it.
  2. Surface plants float on water have broad leaves that contain numerous stomata on the upper side of the leaf, which trap maximum light for photosynthesis.
  3. Possession of small feathering roots.
  • Less rigid structure because water pressure support them.
  • They have succulent stem.
  1. Numerous stomata are opened at all times.

Examples of hydrophytes include water lily, water lotus and water hyacinth.



Adaptation of Mesophytes

Mesophytes are terrestrial plants that grow in areas of moderate water supply. They are the large ecological group of terrestrial plants. Their adaptive features are:

  1. Possession of well developed root system.
  2. Presence of well developed vascular bundle.
  • Possession of large thin leaves.
  1. Presence of large number of stomata on the under surface of the leaves.
  2. Presence of erect and branded stem.
  3. Possession of mesophyll layer that is well differentiated with many intercellular spaces.

Examples include maize, sunflower, cassava, hibiscus, mango and orange.


Adaptation of Xerophytes

Xerophytes are plants that grow in dry areas with little water or moisture such as desert. Their adaptive features are:

  1. Reduced leaves that are reduced to spines and tiny scales to reduce water loss.
  2. Reduced number of stomata to reduce water loss.
  • Sunken stomata reduce transpiration.
  1. Large hairs on surface to reduce water loss.
  2. Succulent leaves and stems to store water.
  3. Deep root system to absorb water from depth.
  • Possession of thick, waxy cuticle that reduces water loss through cuticular transpiration.
  • Shedding of leaves during day season to prevent water loss through transpiration.
  1. Possession of ability to fold their leaves during the day to decrease the number of stomata that is exposed, thus reducing the rate of transpiration.

Examples are cactus, euphorbia, Aacia, pine and opuntia.


Jeweled Lizard

This beautiful species also goes by the name of eyed lizard, Lacerta lepida, not because it has eyes, although of course it does, but for the ocelli (“little eyes”), or ringed spots, that adorn its back and flanks. Native to southern Europe and northwestern Africa, the eyed lizard is the largest member of a group of rather unspecialized Old World lizards. The oldest males may reach 80 centimeters (30 inches) from nose to tail tip. Better known to many Europeans are two smaller members of the genus, the wall lizard and the common or live-bearing lizard, which has the unusual habit of producing its young not in the leathery-shelled eggs typical of reptiles but in a thin membrane whose confines they immediately tear out of to assume life as full-fledged lizardlings.


Adaptation of animals to Terrestrial Habitat

  1. Most terrestrial organisms possess well developed supporting or skeletal systems.
  2. The flight birds and mammals possess light skeleton to enable them swing in the air.
  • The climbing animals possess long curved claws for support or nuptial pads to help them grip surfaces.
  1. Some grassland and desert animals exhibited protective colouration to prevent easy detection by predators or prey e.g. chameleons.
  2. The herbivores grace on a variety of forage.
  3. Most weak animals possess keen eyesight and can run fast to escape from their predators.
  • They have well developed sense organs.
  • Some possess impermeable coverage to prevent water loss e.g. monitor, lizard and ant eater.


Adaptation of Animals to aquatic environment

  1. Possession of streamlined body that reduce friction during movement in water e.g. fishes.
  2. Possession of dense, waterproof feathers that keep cold water away from bird’s skin and prevent wetting of feather e.g. birds.
  • Possession of webbed feet, formed from their skin between the toes that work like paddles e.g. ducts.
  1. Possession of gills in fishes and tad poles for gaseous exchange.
  2. Possession of hooks, suckers, sticky under surfaces by stationary organisms for attachment to rock surface e.g. snails, flatworms.
  3. Possession of swim bladder to aid buoyancy in water e.g. Tilapia fish.


Bonito, a relative of the tuna and mackerel, are buit for speed. Bonitos have streamlined, torpedo-shaped bodies that taper to a thin junction with a large, forked tail.


  1. What is adaptation?
  2. Name three forms of adaptation that are notable in organisms.
  3. Define the following and give two examples of each: (a) hydrophytes (b) mesophytes (c) xerophytes
  4. State five ways by which xerophytes adapt themselves to arid condition.
  5. List five ways animals adapt to terrestrial habitat.


All terrestrial organisms face he problem of water loss from their body fluids to the environment. The body fluids of these organisms are maintained by specialized by osmoregulation or excretory organs such as malphighian tubules and kidney. A balance must be achieved between the amount of water lost and gained.

Many aquatic organisms especially those fresh water environment have their body fluids more concentration than their surroundings and as such gain water by osmosis. In order to minimise this, they have impermeable outer covering. On the other hand, those with body fluids less concentrate than their surrounding would lose water to their environment. The water lost is replaced by drinking much water from the environment.


Structural adaptation of Tadpole and fish to aquatic life

  1. Possession of stream-lined body without neck that enhance movement in water.
  2. Possession of a trial fin, which aid in changing of reduction during swimming.
  • Presence of external gills, which serve as the respiratory organ used for oxygen uptake in water.

Becoming a Frog

The legless tadpoles that hatch from a floating mass of frog eggs are the animal’s fishlike larval stage. Part of a true metamorphosis, they have gills and a tail, both of which disappear as the tadpole feeds and grows. When limbs and air-breathing lungs develop, the young frog, now a miniature replica of its parents, emerges from water to land.

Structural Adaptation in birds

  1. Seed-eating birds like sparrow, cardinals and weaver birds have short, thick, conical beaks adapted for cracking seeds or nuts.
  2. Birds of prey like hawks, eagles and owls have sharp, curved breaks for tearing flesh, they also have strong chawlike feet, which they use to capture and kill their prey.
  • Aquatic birds like duck and seagulls have long, flat beaks adapted for straining small plants and animals from the water and for gripping fish and sieving muddy water for food. They also have webbed feet adapted for swimming.
  1. Birds are insect eaters like woodpeckers have beaks that are long and chisel-like for boring into wood to eat insects. Other insect eaters like the nobblers have thin pointed beaks.
  2. Some birds like crows have a multi – purpose beak that is adapted to eat fruits, seeds, insects, fishes and other animals.


The ostrich, Struthio camelus, is a bird of the savannas and deserts of Africa. Its closest cousins-the rheas, cassowaries, emu, and kiwis, as well as the extinct moas and elephant birds-also have or had a southern distribution, in South America, Australia, New Guinea, New Zealand, Africa, and Madagascar. How did these species, none of which can fly, spread across these southern continents and islands? In the time before scientists accepted the theory of continental drift and seafloor spreading, the distribution of the ostrich and its relatives was one of the unaccountable mysteries of biogeography. Now it is considered a classic example of the result of the breakup of the former supercontinent of Gondwanaland, over which the ancestor of all these species is believed to have roamed.


  1. State three structural adaptations of tadpole to aquatic life.
  2. State three structural adaptations of birds to their feeding habits.
  3. Classify plants into three groups on the basis of availability of water to the soil in their environment.
  4. State five adaptive features of xerophytes to arid environment.
  5. List adaptive features of animals to terrestrial habitat.



  1. The features that helps an organisation to survive and exploit its environment is known as (a) modified feature (b) adaptive features (c) enhanced feature (d) structural features.
  2. The characteristics that increase and organism’s potential to survive in its environment is called (a) association (b) adaptation (c) modification (d) tolerance
  3. Which of the following adapts tad-pole to aquatic life? (a)  presence of sharp claws (b) presence of external gills (c) presence of spines (d) possession of short beak
  4. Which of the following does not illustrate adaptation to the environment? (a) Colour changes by chameleon (b) streamline (c) light bones in birds (d) development of big muscles by a weight lifter (e) possession of fins by fish
  5. Which of the following does not illustrate adaptation to the environment? (a) water leaf (b) water hyacinth (c) cactus (d) pines
  6. The changing of colour by a chameleon to that of the environment is an example of —(a) adaptive radiation (b) protective colouration (c) courtship display (d) display of body colour



Discuss the effects of air pollution as a result of oxides of sulphur, nitrogen and dust.


CLASS: SS2                                                                                   


  1. Air Pollution
  2. Noise pollution
  3. Water pollution,

Pollution can be defined in the contamination of the environment due to main activities which releases. Harmful substances into our surrounding in quantities that is dangerous to man and his resources.

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Types of pollution

Types of pollution include the following:

  1. Air pollution,
  2. Noise pollution
  • Water pollution,
  1. Soil pollution,

Substances that pollute the environment are called pollutants thus: there are Air, water, soil and noise pollutants.

 Czech Air Pollution

Factory smoke darkens the sky above Prague, Czech Republic. The Czech Republic faces a severe air pollution problem that is choking the nation’s land. Air pollution and subsequent acid rain has killed or damaged many of the country’s trees and badly degraded its soil.

SUB-TOPIC I. Air Pollution:

From man’s daily activities pollutants such as smoke, gasses and solids are disposes into the atmosphere. Air pollution can also be said to be presence of mixture of gases and solid patches in the air.


Nature of Air Pollution

Pollutants of the atmosphere (Air) include; gases, smoke, oxides of carbon, sulphur and nitrogen such as; carbon (iv) oxide, carbon (ii) oxide, sulphur (iv) oxide and oxides of nitrogen respectively as well as smoke, dust etc. Manufacturing industries, fumes from city Motor vehicles, power stations, combustion of fuels of automobiles and jet planes also release pollutants into the atmosphere. Herbicides, pesticides, aerosol, dust particles, pollen grains fluorides and smog are all pollutants of the atmosphere.


Sources of air pollutants

Fumes, dust, wastes from Construction sites, industries, mines, power station, farmlands, domestic fires, sprayed herbicides and pesticides are sources of air pollutants.


Industrial Smokestacks

Carbon dioxide, sulfur dioxide, and other types of contaminants pouring from industrial smokestacks contribute largely to the world’s atmospheric pollution. Carbon dioxide contributes significantly to global warming, while sulfur dioxide emissions are the principal cause of acid rain in the northeastern United States, southeastern Canada, and eastern Europe.


Effects of air pollution

Pollution of the atmosphere which is Air pollution affects man and his resources in various ways:

  1. Smoke particles make streets and building dirty.
  2. Smoke reduces visibility within the environment.
  • Smoke smog and dust can reduce intensity and quality of sunlight which in turn reduces photosynthesis and automatically crop yields.
  1. Oxide of nitrogen in very high concentration can cause death of animals.
  2. Nitrogen (iv) oxide cause irritation of the eyes in humans.
  3. Carbon (ii) oxide can easily combine with haemoglobin that can reduce the oxygen carrying capacity of blood.
  • Sulphur (iv) oxide a pollutant resulting from the activities of petroleum refineries, poisons plant and lower their yield.
  • Sulphur (iv) oxide causes respiratory diseases as it damages respiratory organs.
  1. It makes the soil highly acidic as it forms tetraoxosulphate (iv) acid in rain water and affects plant growth negatively.
  2. Dust particles in the atmosphere reduces visibility and intensity of sunlight, dust in water spoils its quality for drinking.
  3. Pollen grains present in dust trigger off bouts of lung disorders such as asthma.
  • Smog reduces visibility, hours of sunlight and could be dangerous for motorists.


Exxon Valdez Oil Spill Cleanup

Workers wash the shoreline on Latouche Island, Alaska, after the Exxon Valdez oil tanker ran aground in 1989, dumping more than 38 million liters (more than 10 million gallons) of oil into Prince William Sound. The resulting environmental damage prompted the United States Congress to pass federal safety requirements for oil tankers and barges and to assign the principal cost of spill cleanup to oil companies.


Control of air pollution

  1. Industries should be sited for away from residential and commercial areas.
  2. Chimney pieces should be used in houses, industries and similar places to release their pollutants for from ground level.

Noise is defined as any unpleasant and unwanted sound in the air. Noise pollutants therefore include the followings: blowing of vehicles horns sounds from factories, loud music, foundries, electric generators, sounds from mosque, some churches bomb blasts, cannon and artillery gum fires.

Sources of noise pollutants

  1. Low flying aircraft.
  2. Factory or industrial noise
  3. Automobiles
  4. Locomotive engines
  5. Car horns and sirens
  6. Guns of various types
  7. Bombs; especially atomic bombs.
  8. Musical sets, Radio and television tuned to highest volume.
  9. Noise from generating plants
  10. Noise from thunderstorms.

Effects of noise pollution

  1. It causes restlessness as it quickens heartbeat and blood circulation.
  2. It causes headache and discomfort
  3. It could prevent some people from sleeping.
  4. Prolonged high-intensity noise can damage ear drums and causes deafness.

Control of noise pollution

  1. Legislation should be made against the use of loud speakers in public places
  2. There should be installation of sound proofs in industries and generators
  • Rail ways and airports should be sited far away from residential areas.
  1. There should be reduction of noise from loud speakers and car sirens
  2. In Quarries, airport and factories where noise levels cannot be reduced, ear-muffs should be used.


  1. Define (i) pollution (ii) pollutant
  2. List the different types of pollution
  3. Explain the nature and sources of air pollutants
  4. Outline five Air pollutants and explain their effects on man.
  5. Explain ways of controlling air pollutant.


Water pollution is the process whereby harmful waste materials are deposited into water bodies making unfit for aquatic life and human consumption.


Sources of water pollution

Water bodies such as estuaries, rivers, streams, lakes and seas get polluted when diverse materials and toxic wastes from domestic and industrial activities of man are dumped into them. Rain water also get polluted as carbon (iv)oxide from the air get dissolve into it.

Industrial Water Pollution

Industrial pollutants that run into streams, rivers, or lakes can have serious effects on wildlife, plants, and humans. In the United States there are strict rules for the amount and composition of substances that factories can release into bodies of water. These rules are not always enforced, and much industrial water pollution comes from accidental chemical or oil spills.

Types of water pollution

  1. Refuse and sewage.
  2. Industrial waste.
  • Agricultural wastes (herbicides, pesticides, insecticides and fertilizers)
  1. Crude oil spillage

Life of plants and animals in water bodies and even eliminated by water pollutants.


Effects of oil spillage

When oil tankers are loading and off –loading, some of the oil spills and get back to the river and estuaries. Explosion at offshore rigs releases great quantities of oil and when oil tankers wreckages results in oil spillage.

Oil spillage can cripple economic life of fisherman and farmers in affected areas. The spilled oil forms a coat on the surface of the water cutting off oxygen supply from plants and animals in the water.

Spilled oil also contaminates the source of drinking water for inhabitants of such areas thereby making life difficult and uncomfortable.

Destructive Oil Spill

The Prestige, an aging, single-hulled oil tanker, ruptured in a storm off the coast of northwestern Spain on November 13, 2002. The tanker sank six days later, spilling millions of liters of oil that fouled beaches from northwestern Spain to southwestern France.


Control of water pollution

  1. Refuse and sewage should be treated and efficiently disposed.
  2. Enlightenment of public on proper disposal of human faeces, wine and domestic refuses.
  • Indiscriminate dumping of industrial wastes in water bodies should be avoided. Recycling of industrial effluents should be encouraged.
  1. Farmers should be educated on proper use of fertilizers, pesticides, insecticides ad herbicides.
  2. All necessary precaution should be employed to avert oil spillage.


  1. Which of the following is air pollutant (a ) detergent (b) crude oil (c) untreated sewage (d) smoke
  2. Which of these is not an Air pollutant? (a) carbon (ii) dioxide (b) oxide of nitrogen (c) carbon (iv) oxide (d) sulphur (iv) oxide
  3. One of these cannot cause noise pollution? (a) smoke (b) high intensity and unpleasant noise (c) industrial (d) actions (d) generation
  4. One of these is false (a) soil is polluted by clearing refuse dumps (b) oil spillage cripples economic life of fishermen (c)water pollution is dangerous to water supply (d) noise pollution may cause restlessness
  5. Long term effects of air pollution does not include (a) lung cancer (b) irritation of the eyes (c)chronic respiratory diseases (d) heat damage


  1. Define soil pollution
  2. State three sources of soil
  3. State three effects of soil pollution
  4. Give three control measures of soil pollution. 


  1. Carry out an experiment to estimate the amount of pollution in rain water (page 154 of your modern biology text book).



CLASS: SS2                                                                                   


(1) Meaning of conservation and natural resources

(2) Ways of ensuring conservation of natural resouces

(3) Benefits of conservation.




Conservation is the diligent and wise use of the earth’s resources to achieve the highest quality of living for all mankind on sustainable basis.


Natural resources simply mean the endorsement of nature from which man satisfies his basic needs.


Conservation of natural resources can therefore be referred to as “the controlled exploitation and diligent use of available natural resources in such a way as to sustain their availability”. It is the preservation of the amount of nature of the environment.


Recycling Aluminum Cans

The Alcoa Recycling Company in New Jersey processes aluminum cans into large bales at a collection point. In an effort to conserve nonrenewable natural resources, many industries and individuals recycle waste aluminum.


Natural resources can be classified as a:

  1. Natural abiotic resourceswhich are non-living or non-replaceable. E.g. ores and materials extracted from the ground.
  2. Natural Biotic resourceswhich are living or replaceable e.g. wildlife, forest, water, air, sunlight etc.

Natural resources that need to be conserved are

  1. Natural forest
  2. Animal/wild life
  • Water
  1. Soil
  2. Air
  3. Mineral resources


Importance of conservation of natural resources.

There is the urgent need for the effective conservation of natural resources if mankind is to get maximum and lasting benefit from nature. The following reasons necessitate the conservation of natural resources:

  1. Fast depletion of natural forest through overlogging and over grazing.
  2. Risk of extinction of indigenous wildlife and fish species through uncontrolled hunting and fishing.
  • Rapid soil degradation through poor land use and obsolete agricultural practices.
  1. Pollution of surface and ground water resources through indiscriminate disposal of all kinds of wastes.
  2. Desert encroachment.
  3. Bad mining practice.
  • High population growth.


Resources that need to be conserved are:

  1. Non-renewable resources like fossil fuels (crude oil), minerals.
  2. Renewable resources like water, wildlife, forest.


  1. What is meant by conservation of natural resources?
  2. What are the divisions of natural resources?
  3. State 4 reasons why conservation of natural resources is important to a nation.
  4. Mention 5 natural resources that need urgent conservation in your area.



The responsibility of conservation of natural resources should be the collective effort of both government and individuals.


These efforts should include the following:

  1. Government agencies:the primary task of these bodies is to see to the protection and conservation of specific areas of concern. Examples are Ministry of Agriculture and Natural Resources, Forest Reserved Authority, Conservation Foundations etc.
  2. Legislation:these are usually law and treaties put in place by National and international governments and organization to protect undue exploitation of endangered species and other forms of resources. Examples are Anti-whaling law, prohibition of bush burning and tree felling and law against gas flaring.
  • Conservation Education: this effort aims at bringing awareness and public enlightenment to the general public on the essence of conservation. Special programmes aimed at involving all and sundry in the practical activities of conservation are also effective.
  1. Erection of parks and reserves: this strategy involves the identifying of unique areas and setting them aside for the protection and conservation of plants and animals. E.g. Yankari, Kainji, Olokemeji forest.

Tanzania Game Reserves

Tanzania devotes a substantial portion of its land to conservation areas in order to preserve its indigenous east African wildlife. These reserves, which include Serengeti National Park, Selous Game Reserve, and Ngorongoro National Park, provide a home to animals such as elephants, baboons, zebras, and giraffes. This picture shows a migration of gnu at Ngorongoro.

Nutria or Coypu

It is an irony of conservation biology that a species might be in need of protection in its native lands while it is persecuted as a rampant pest in places where it has been introduced. That is the case of the nutria, or coypu, Myocastor coypus, an aquatic rodent that hails originally from the marshes, streamsides, and lakeshores of southern South America. Overtrapping and wetlands destruction have caused many South American nutria populations to decline to the point that they have been granted official protection. Yet populations of nutrias introduced as furbearers to parts of North America and Eurasia have proved so successful that vigorous control measures must be applied to keep the numbers of these destructive rodents in check.


Some problems militating against the above efforts at conservation are:

  1. Over populationwhich leads to increase demand on limited resources thereby causing undue exploitation of resources.
  2. Inadequate awarenessdue in part to the failure of governments in conservation education and ineffective public awareness campaign.
  • Poor fundingresulting in the poor or non-implementation of government policies and programmes on conservation.
  1. Limited landfor the establishment and maintenance of games and forest reserves and other related conservation projects.


  1. Who should bear the responsibility of conserving natural resources in a nation?
  2. Mention and explain 3 ways of ensuring conservation of natural resources.
  3. Why is it difficult to achieve effective conservation of natural resources.
  4. In what practical ways can you contribute to the national effort of conservation.



Recommended:  Civic Education Lesson Note for JSS3 (First Term) 2023

Apart from ensuring sustained availability of high quality resources for mankind basic needs, conservation of natural resources will afford the following benefits:

  1. Improvement of the quality of human life in a clean and healthy environment.
  2. Preservation of the beauty of the natural environment of scenery such as lakes, waterfalls, mountains etc.
  • Boost of tourism to national parks and reserves.
  1. Great scientific benefits as living organisms are studied in their natural habitats.
  2. Protection of rare and/or endangered species of organisms.
  3. Prevention and control of erosion and desert encroachment.
  • Prevention of exploitation of mineral resources.



  1. Define conservation of natural resources.
  2. With two examples each distinguishes between abiotic and biotic natural resources.
  3. State three reasons why conservation of natural resources is important to a nation.
  4. Explain the reasons why water as a resource need to be given special attention to conservation.
  5. In what practical way can conservation education be used as an effective tool in government’s hand to control natural resources?
  6. Discuss any four challenges facing the nation in her effort to effectively conserve essential natural resources.
  7. In what ways has conservation of resources benefited the nation? Give practical examples.



  1. Effective control of natural resources by man is described as (a) Utilization (b) Evaluation (c) Conservation (d) Integration (e) Development
  2. The following natural resources are renewable except (a) water (b) Crude oil (c) Air (d) Soil (e) Plants.
  3. One of the methods of ensuring conservation of natural resources may be by (a) bush burning (b) felling of tree (b) mechanised farming (d) establishment of forest reserves (e) continuous cropping.
  4. The need for preserving and conserving natural resources is most urgent these days due to _____ (a) fast depletion of natural forest resources (b) high rate of corruption (c) low prices of materials from the forest (d) bad government policies (e) slow rate of desert encroachment.
  5. One of these is not a benefit of conservation of natural resources (a) poor patronage by tourists to waterfalls (b) great scientific value (c) preservation of natural beauty (d) sustained availability of resources (e) conservation of endangered species.


  1. List 5 challenges facing conservation of natural resources in Nigeria and suggest possible   solutions to them.
  2. List 5 game reserves in Nigeria and where they are located.
  3. State four conservation agencies in Nigeria.
  4. State two methods each of conserving the following natural resources.
    1. Natural forest
    2. Animal/wild life
  • Water
  1. Soil
  2. Air
  3. Mineral resources






(I) Life cycles of pests

(II) Control of pests

(III) Diseases caused by pest and their agents

(a) Fungal diseases

(b) Viral diseases

(c) Bacterial diseases

(IV) Control of pest.



Pests are organisms that carry disease or cause damage to other organisms. Pests may be plants or animals. Plant pests are usually called weeds. Pests are very important to man because of their detrimental effects to humans and other organisms of concern to man e.g. agriculture or livestock production.

Crop pests are those that affect agricultural produce important to man, e.g. insects, birds etc. Livestock pests attack livestock useful to man e.g. Mites, Lice, Tapeworms.

Pests usually decrease the quantity and quality of agricultural production, especially when present in large numbers.

Crop-Destroying Weevils

Weevils are among the most destructive of pests that attack agricultural crops. Adult weevils lay their eggs in stalks or seeds of crops such as cotton, wheat, rice, and alfalfa. As larvae, weevils then feed on these plant tissues, extensively damaging the plant in the process. 


  1. What are pests?
  2. What make pest so important to man?
  3. Mention 3 common pests you know. 


Classification based on the various parts of a crop plant they attack:

  1. Stem borers: these are usually larvae of certain moths that bore into the stems of maize and feed on it. This result in the weakening and breaking of the stem.
  2. Root feeders: these are insect larvae or adults found in the soil. They burrow into the ground and feed on yam tubers.
  • Leaf feeders: snails, bettles, grasshoppers eat up leaves of crops.
  1. Young shoot feeders: aphids, mealy bugs and scale insects usually pierce and suck out juices from young shoots. Many sucking pests also transmit disease-causing organisms to the plants e.g. Cassava leaf mosaic virus is transmitted by white flies. Such pests are known as vectors.
  2. Fruits and seed feeders: these are moths, fruit flies, cotton strainers and some beetles eat their way into fruits and seeds causing great damage.


Damaged Crops in North Korea

A North Korean farmer assesses the damage done to his corn crop by poor growing conditions. In the mid-1990s severe flooding followed by droughts devastated the country’s agricultural output and led to serious food shortages. By the late 1990s North Korea was experiencing widespread famine.


Other invertebrate and vertebrate pests include:

  1. Insects like flies, aphids
  2. Mites and ticks.
  • Snails
  1. Flatworms
  2. Tapeworms
  3. Protozoa
  • Birds
  • Rodents

Aphids on a Cabbage Plant

Aphids are small insects found throughout temperate regions of the world. They parasitize a variety of wild and commercially important plants by sucking out plant fluids. Because aphids exude a sweet, sticky fluid that can be used by certain species of ants, herds of aphids are often found guarded and tended by ants.


  1. Briefly describe how pests affect root tubers.
  2. Explain the term Pests. What make them so important to man?
  3. In what ways do Pests affect the quality and quantity of agricultural livestock produce?
  4. Mention 5 pests and describe the ways they attack crops and their effect on crops.
  5. In what way has mono-cultural practice in commercial agriculture contributed to the emergence of pests as a production factor?


  1. Pests are important to man because (a) they are rich source of protein (b) they contribute greatly to soil fertilizer (c) they affect valuable agricultural produce (d) they reproduce profusely (e) they are lower than man.
  2. Which of the plant part is usually NOT attacked by pests? (a) flowers (b) stems (c) leaves (d) roots (e) fruits.
  3. Which of the following crops is attacked by a stem-boring pest? (a) mango (b) cassava (c) maize (d) yam (e) groundnut.
  4. An example of an invertebrate pest is ______ (a) adult housefly (b) aphids (c) Mosquito (d) Butterfly (e) amoeba
  5. Which of the following vertebrate is not a known pest (a) Dog (b) birds (c) Squirrel (d) rabbit (e) Monkey


Most insect pests have the following stages in their life cycle i.e. egg, larva, pupa, adult.

The adult pests usually feed on leaves and fruit of crops. Larva chews the bark of stems and feed on the phloem thereby damaging the crop. Insect pests go through either complete or incomplete life cycles but the larval and adult stages have been seen as causing most serious damages to crops.


Some examples of insect pest life cycles:

  1. Yam beetle (undergoes complete metamorphosis), The adult feed on yam tubers in the ground.
  2. Cotton Stainer (undergoes incomplete metamorphosis), the adults attack and damage cotton toll.


  1. What is meant by life cycle?
  2. Explain the two types of life cycles.
  3. Draw the life cycle of a named pest.



Control of pest refers to the management and prevention of pests with the sole aim of minimizing their effect on crops and livestock thereby maximizing food production.


Pest control focuses on:

  1. Reduction in pest population.
  2. Protection of crops.

For effective control of pests, a good knowledge of pests’ habits and life cycles is vital. Careful study of the above will reveal the following for good use in control:

  1. Stage and peak period of attack.
  2. Resting stage after attack.
  • Most vulnerable stage for control.


Various methods have used to good effect in controlling pests.

  1. Physical methods:these methods involve collection of pest by hand or traps are killing them. Burning, flooding and the use of scare-crows are ll methods controlling pests physically. This could be carried out in a limited are involving large-sized pests as snails, beetles, birds etc. Physical experiences are usually tedious and strenuous.
  2. Cultural Methods: these involve modified farm practices like bush fallowing, crop rotation, mixed cropping, closed-season practice and changing planting time. The aim is make environmental condition unfavourable for the development of pests. Such methods are most effective because most pests are plant specific.
  • Biological methods: this involves the use of natural predators and parasites on the pests. Extracts from sources can also be used in pest control. Such are inexpensive and long lasting.
  1. Chemical methods:this involves the use of pesticides such as insecticides, fungicides, herbicides, and rodenticide. The aim is to kill or reduce pest population thereby protecting the crops from attack. Though effective the numerous negative side effects of chemical pest control have posed serious concern.

Apart from the specified methods discussed above, there are modern developments in pest control. Sterile male technique and use of chemicals attract and repel pests are in use. The combination of control practices (integrated method) and knowledge of life cycle of pests has also proved effective.



  1. What is pest control?
  2. For an effective control of pests, what should be the focus?
  3. List 3 methods of pests’ control.
  4. Mention 3 pests and indicate the chemical agent used in their control.



  1. Fungal diseases:Fungi diseases in crops are caused by Fungi which are usually microscopic and parasitic. Fungal diseases attack the leaves, roots and stem of plants. E.g Smut, rust, blight, root rot, and downy mildew are fungal diseases.
  2. Viral diseases:these are diseases which are parasites. Common symptoms include Mosaic motting, lesions, chlorosis, stunting and recrosis. Many plant viral infections are spread by insect vectors like aphids, beetles and hoppers. Crops affected by viral diseases are Tobacco, Cassava, and garden egg.
  • Bacterial diseases:these are caused by bacteria which tend to form spotting of leaves, stems and fruits. Bacteria also cause soft rots, bacterial blight, bacterial wilt and bacteria galls.



Fungal Diseases of Plants

Most types of plant-related diseases are caused by fungi. The leaves of this plant have been infected by tar-spot fungus. Fungi can infect all parts of the plant including leaves, stems, flowers, roots, and fruit. The physical manifestations of fungal diseases of plants include wilting, club root, root rot, wood rot, cankers, various types of mildews, blights, lesions, and leaf spots. The effects of fungal diseases can be devastating as evidenced by the potato blight that destroyed the Irish potato harvest of 1845 and caused a widespread famine in Ireland.



  1. What are the causative agents of pest diseases in crops?
  2. List 3 symptoms of viral diseases.
  3. Which plant parts are usually affected by fungal diseases?



Control of diseases caused by pests involves:

  1. Physical methods: this involves removal of diseased plants. Weed hosts are also removed. Bush burning and soil flooding are other methods.
  2. Cultural methods:this involves the modification of farming practices to destroy disease-causing agents. Early planting and use of balanced fertilizers enable plants to be well established before the peak period of infection. Planting resistant varieties also help control diseases.
  • Chemical methods:this involves the use of chemical agents to either eradicate the crops from such agents. These are best methods of diseases control.
  1. Integrated method: this involves the combination of two or more methods highlighted above, for effective disease control.


Other methods are:

  1. Prevention of crops from being infected by disease-causing agents.
  2. Destruction of disease-causing agents and their respective vectors.
  • Prevention of disease plants or animals from entering into country by government.
  1. Distribution disease-free planting materials.



  1. How are fungal diseases by pests controlled in crops?
  2. What is usually involved in the cultural methods of the control of plant diseases caused by pest?
  3. In a tabular form, outlines 5 common pests of crops, their symptoms and their control.
  4. Explain 4 pest control methods applicable to crops.
  5. Discuss the benefits and disadvantages of the use of Biological and chemical methods of pest control.
  6. What is crop rotation? Explain its benefits to pest control.


  1. Which of the following sequence is true (a) egg-adult- Nymph- Pupa (b) egg-pupa-larva-adult (c) egg-larva-pupa-adult (d) egg-nymph-adult (e) egg-larva-nymph-pupa-adult.
  2. Which of these stages causes the leastdamage to crops? (a) Nymph and Adult (b) Pupa and Larva (c) Larvae and Adult (d) Adult and Pupa (e) egg and Nymphs.
  3. Pest control involves the following except(a) reduction of pest population (b) protection of crops (c) good knowledge of life cycle of pests (d) good knowledge of pest habits (e) good study of the structure of the pests.
  4. The use of sterile male technique is relevant in the _______ (a) study of the sex of insects (b) study of the population of insect (c) study of economic importance of insects (d) chemical method of pest control (e) modern means of pest control

Hope you got what you visited this page for? The above is the lesson note for Biology for SS2 class. However, you can download the free PDF file for record purposes.

If you have any questions as regards Biology lesson note For SS2 class, kindly send them to us via the comment section below and we shall respond accordingly as usual.





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