POLLUTION

POLLUTION
By the end of the lesson, students should be able to:
Define pollution.
Name air pollutants and their sources.
Enumerate the harmful effects of pollutant.
State effects of detergents, insecticides, artificial fertilizers and herbicides on aquatic and terrestrial organisms.
Identify poor sewage system as a source of pollution.
Name domestic and industrial wastes that pollute land and water.
Identify the decay of organic matter (e.g. dead animals and plants) as a source of pollution.


Pollution is the release of impurities or toxic or harmful substances or chemicals or energy into the environment by the natural forces or man and other animals to an extent that causes biological damages to man, natural resources, and other organisms.

What brought about pollution? Or how does pollution occur?
Man's effort to sustain his life due to increased  population size, resulted in increase in agricultural activities to get food for the increased population, and increase in industrial activities to raise a standard of living; these activities brought about discharge of chemicals, wastes and energy which accumulate in the ecosystem and hence resulted in imbalance, threat to lives and destruction of natural resources.

POLLUTANT
A pollutant is any harmful substance introduced into the environment by natural forces, man and other animals that causes the destruction or impairment in the environment. Examples are carbon dioxide, smoke, noise, refuse and sewage etc.
Major sources of pollutants:
Industrial activities i.e. Wastes (e.g. Carbon dioxide, sulphur dioxide etc), and energy (e.g. heat, sound and radiation)
Agricultural activities i.e. fertilizer application, use of insecticides, pesticides, herbicides, and other farming methods.
Natural processes such as excretion and volcanic eruptions.

Note: pollutants can be grouped into two. These are:

Biodegradable pollutants: These are pollutants which can be broken down into simple harmless substances, which when present in large volume in the ecosystem tend to be poisonous due to inability of the ecological cycle to cope with. e.g. any products of living organisms e.g. decayed body, waste , such as faeces, urine etc are examples.

Non-biodegradable pollutants: These are pollutants that accumulate in the environment, which cannot be broken down into simple harmless substances e.g. glass, plastics, nylon etc

                  TYPES OF POLLUTION
There are three major types of pollution. These are:
1. Air or atmospheric pollution;
2. Water pollution;
3. Soil or land pollution.

1. Air or atmospheric pollution
This is the addition of air-borne substances such as dust, smoke, noise, soot, radioactive energy, carbon dioxide, hydrocarbons into the air, which alters the composition of the atmosphere, causing harm to both plants and animals and resulting in ecosystem imbalance.

              Control of Air/Atmospheric Pollution
Proper maintenance of machinery, automobiles, furnaces and chimneys, through efficient burning to reduce release of gases such as carbon monoxide and soot.
Removal of sulphur compounds from coal and low-grade fuel oils before use.
Industries should be sited far away from residential areas
Legislation should be made against indiscriminate burning that may bring about smoke.
Chimneys should be filtered to remove pollutants
Banning of all chemicals that react with ozone to decrease the ozone layer.
Furnaces and car engines that operate at lower temperatures should be built to reduce the production of the oxides of sulphur and nitrogen
Using unleaded petrol or petrol with low lead levels

                       Definitions of terms used

Fallout: this is the tiny radioactive particles/dust that fall to earth after a nuclear explosion.

Chlorofluorocarbons : the family of synthetic chemicals that are compounds of the elements chlorine, fluorine, and carbon.

Noise: an unpleasant and irritating sound. The loudness of sound is measured in decibels (dB)

Photochemical smog: a form of smog formed when sunlight causes the oxides of nitrogen and unburnt hydrocarbons to react chemically.

2. Water Pollution
This is the discharge into water of any substance which may become harmful to aquatic organisms and unfit for human use.

Sewage: this is a waste matter/faeces, urine, waste water from animals/industrial/domestic sources; that is dissolved/suspended in water.

Effects of releasing untreated sewage into a stagnant water body

Spread of water-borne diseases
May be toxic/poisonous to aquatic life/organisms
Makes water unfit for consumption/use
Increased decomposition
Increased concentration of nutrients
Rapid growth of algae/aquatic plants/algal bloom/eutrophication
Depletion of oxygen
Suffocation/death of aquatic animals
Generates offensive odor/air pollution
Nutrient/nitrate/phosphate enrichment/accumulation in a water body; as a result of breakdown by bacteria.

Refuse: This is a dry or wet waste from paper scraps to abandoned vehicles collected from homes, offices, hospitals, schools, factories, and markets.

Eutrophication: This is the excessive growth of plant life usually algae i.e. algal bloom in water body caused by an increase in organic nutrients and minerals leading to the death of aquatic organisms.

Causes of eutrophication

Overuse of fertilizers/plant nutrients which drain off into water bodies
Sewage discharge
Wastes from fish farming

Effects of eutrophication

It reduces oxygen level in water
The death of algae leads to anaerobic decomposition which may breed some pathogens causing diseases
Renders water useless for man's use and consumption
Death of aquatic animals due to suffocation
The death of aquatic animals and plants result in foul odor hence air pollution occurs.

Class work
How would you control eutrophication?
If you were Nigeria president, how would you solve  the problem of water pollution in the Niger Delta and Lagos metropolis?
Discuss biochemical oxygen demand (BOD) and use it to explain indication of water pollution.
Discuss the effect of pesticides such as DDT in a food chain.
How does the phosphates in the treated sewage cause pollution problem?

Control of water pollution

There should be efficient and proper sewage disposal system
Public enlightenment on waste disposals
Industrial effluents should be recycled rather than being discharged into water bodies
The use of fertilizers and other manure should be regulated to avoid washing or leaching into water bodies
Oil spills should be prevented by using latest techniques of handling crude oil or petrochemicals
Industries should be checked by government using Environmental Impact Assessment before being sited/located
Government should provide good centralized sewer to convey sewages and such should be recycled.

      Methods of purifying water
Boiling
Addition of chemicals such as alum, chlorine
Filtration
Distillation
Sedimentation and boiling
Sterilization such as using ultra violet light.

Note: all sewage are biodegradable but not all refuse are biodegradable.

3. Soil or land pollution
This is the discharge into the soil of rubbish and chemicals which may become harmful to plants and animals including man and make soil infertile.

Control of land/soil pollution

Refuse should be burnt in incinerators
Urban wastes should be properly burnt or buried
Sewage should be properly treated before disposal
Legislation should be made by government against dumping of harmful wastes
Pesticides, herbicides and fertilizers should be applied as instructed
Metal scraps, bottles, cans, and vehicles should be recycled
Oil pipelines should be maintained and checked regularly to prevent sabotage or natural oil spillage
Farming practices should be properly checked to avoid erosion
Overgrazing of pastures should be avoided
Restoration of land where mining took place to prevent indiscriminate mining activities

NUTRIENT CYCLING

NUTRIENT CYCLING

At the end of the lesson, students should be able to:
Describe how carbon circulates in nature.
Draw the carbon cycle in detail.
State why the carbon cycle is used necessary for life.
Recognize the delicate balance between carbon and oxygen.
Describe the role played by plants and animals in water cycle.
Draw the water cycle in detail.
Describe with the aid of diagram the role of nitrogen.
State that energy can be obtained by decomposing organic substances.
Identify one of the gases produced during decay.


Nutrient Cycling
Nutrient cycle or ecological cycle is the movement and exchange of organic and inorganic matter back into the production of living matter. It occurs within ecosystem, since energy flow is unidirectional hence, the movement of mineral nutrients should be cyclic. Mineral cycles include: nitrogen cycle, water cycle, oxygen cycle, sulphur cycle e.t.c.

Carbon Cycle
Carbon cycle involves the series of processes in which carbon is continuously being removed from and added to the carbon dioxide in the atmosphere and the ocean.
Process of carbon cycling

The processes of carbon cycling include:
Removal (or absorption) of carbon from the air and water;
Addition of carbon into the air.

Removal (or absorption) of carbon from the air and water:

Photosynthesis: carbon dioxide is removed from the air (atmosphere) by photosynthesis during which plants use it to manufacture their food.
Leaching and drainage: Carbon is lost in form of carbonates of calcium and magnesium through leaching and drainage.

2.   Addition (or returning) of carbon into the air (atmosphere) and water:

Combustion: burning of fossil fuel like coal and and other crude oil, and wood are sources of carbon into the air.
Respiration: The release of gas during exhalation and fermentation send carbon out in form of carbon dioxide.
Decomposition: The death of all organisms bring about decay, and this results in release of  locked up carbon as carbon dioxide.
Diffusion of carbon dioxide from seas and other bodies of water acting as reservoir of carbon dioxide.
The action of volcanoes (i.e. volcanic eruption)which releases carbon dioxide.

Importance of carbon cycle in nature
Plant uses carbon dioxide obtained from the air to produce their food.
It is the major block of all organic matter.
It helps to purify the atmosphere and maintain atmospheric level of carbon dioxide.
Organic matter which is made from carbon helps to replenish soil nutrient.

Oxygen Cycle
Oxygen cycle involves the circulation of oxygen between the living organism and the non living things.

Process of oxygen cycle

The process of oxygen cycling include:
Removal/ or absorption of oxygen from the air and water;
Addition of oxygen into the air.

1. Removal of oxygen from the air and water:

Respiration in both plant and animal;
Combustion of fuels;
Decay of dead organic matter.

2.    Addition of oxygen into the air and water:
Photosynthesis.
Note: Oxygen cycle is the carbon cycle in reverse!

Importance of oxygen cycle in nature

It brings about life sustenance.
It makes carbon dioxide readily available for photosynthesis.
It purifies the air by avoiding pollution.
Oxygen cycle, if not altered, ensures balance in nature.
Carbon-Oxygen Balance
Many human activities increase the level of carbon dioxide, while oxygen is left at a very low pace.

Such activities that deplete oxygen level in the atmosphere include:

Deforestation;
Combustion of fuel;
Overpopulation which increases respiration rate;
Decay of many dead animals through war, and other means;
Burning of bush indiscriminately.

 If the activities mentioned above are not checked, they result into the following:

Climate change which could affect the important food-growing areas of the world. Hence, this result in food shortage;
Death of many aquatic organisms e.g. fish.
Greenhouse effect (i.e. an increase in the retention of the sun's radiant energy)
Global warming (i.e. an average increase in the earth's temperature which in turn causes changes in climate) which may result in melting of the polar ice-caps with a related rise in sea level.

Suggested solution to maintain a balanced carbon-oxygen level.

Limiting the use of land fill sites to reduce production of greenhouse gases such as methane, carbon dioxide, sulphur dioxide etc;
Limiting deforestation and encourage afforestation;
Exhaust fumes of vehicles should be properly checked to ensure that carbon dioxide and other gases are emitted are reduced;
Education and enlightenment on the effect of man's activities that alter oxygen level;
Birth control measure should be adopted to discourage overpopulation;
Production of chlorofluorocarbons must be discouraged.



Water Cycle
Water cycle is the continuous movement of water from the atmosphere to the earth and from the earth to the atmosphere.

Process of Water Cycling in Nature

The process of water cycling include:

Removal/ or absorption of water from the air;
Addition of water into the air.

1. Removal of water from the air/atmosphere involves all forms of processes in which land receives water. These processes include:
Rainfall or precipitation.
Infiltration and percolation.

2.   Addition of water into the air/atmosphere include all processes in which the atmosphere receives water. These processes include:
Evaporation from oceans, seas, rivers and land (e.g. from decay, excretory wastes, run off water etc)
Transpiration from plants.
Breathing or respiration by plants and animals.

Importance of water (cycle) to living organisms.

Maintains osmotic content of body.
Medium of transport of nutrient for both plant and animal.
Required for seed germination.
Provides medium for absorption of mineral salts by plants.
Aids excretion of waste products.
Provides a natural habitat for aquatic organisms.
It is an essential raw material in the process of photosynthesis.
Regulates body temperature i.e. thermoregulation.
It acts as a solvent for soluble food substances in digestion of food.

EXPERIMENT 1
Aim: To show the absorption of carbon dioxide and release of oxygen during photosynthesis.
Materials required: three beakers, test tubes, funnels, water plants, glowing splint.


Method: set up three set of apparatus as shown above. Distilled water is put in A, B, and C and then filled with water saturated with carbon dioxide.
Place C in a dark cupboard and A in bright sunlight and B in dim light until some gas has collected in one of the test tubes.
Test the gas in the test tube with a glowing splint, to find out if it is oxygen.
Observation: (tabulate your observation as shown below)


From this table, using glowing splint to test the presence of oxygen, it is observed that flask  C did not produce oxygen while flasks A and B produced oxygen.
Conclusion: The experiment simply shows that carbon dioxide and sunlight are required by plants🌿 during photosynthesis and during the process, oxygen is released to the environment.

EXPERIMENT 2
Aim: To show that water is given off during transpiration.
Materials required: Two polythene bags, two bell jars, anhydrous white copper II tetraoxosulphate VI, two potted plants (with one having its stem cut) and crucible.

Method: Place the copper II tetraoxosulphate VI (CUSO4) in a crucible along with the potted plant, covering the soils with the polythene bag. Repeat same with the control. Cover the white anhydrous copper II tetraoxosulphate VI with bell jars.
Observation: The white anhydrous copper II tetraoxosulphate VI in the main experiment turns blue while the control did not change colour.
Conclusion: The change in colour is due to the water given off during transpiration through the leaves.
Class work.
Using experiment 2 above, explain why;
the pot is enclosed in a transparent polythene bag;
the stem above the soil is smeared with a layer of vaseline.

Nitrogen Cycle                            
The nitrogen cycle is the pathway along which nitrogen moves through living and non-living components of the ecosystem to continuous uses.

Process of Nitrogen Cycling in Nature

1. Removal of atmospheric nitrogen: This is conversion of gaseous nitrogen into nitrates. This occurs in the following ways:

Nitrogen fixation by some free bacteria: Some bacteria can convert free atmospheric nitrogen in the soil to produce nitrates. Examples are  Azotobacter, Clostridium and Rhodospirillum.
Nitrogen fixation by symbiotic bacteria: Some bacteria have symbiotic association with roots of some leguminous plants ( such as groundnuts, beans, Crotalaria). They form nodules in which atmospheric nitrogen is converted to nitrates and absorbed by by the plant to form proteins. Example is Rhizobium leguminosarium.
Note: The Rhizobium bacteria are not capable of fixing nitrogen if they are free from leguminous roots.
Action of blue green algae: The blue green algae are capable of converting/fixing atmospheric nitrogen into nitrate. Examples are Anabaena and Nostoc.
Electrical discharge: During thunderstorms, the lightening produced causes the atmospheric nitrogen to combine with oxygen to form nitrogen (II) oxide i.e. N2 + O2 →2NO. The nitrogen (II) oxide reacts with oxygen to form nitrogen (IV) oxide i.e. 2NO + O2→ 2NO2. The nitrogen (IV) oxide reacts with rain water to form a weak solution of trioxonitrate (V) acid and dioxonitrate (III) acid i.e. 2NO2  + H2O → HNO3 + HNO2 . When this weak acid reaches soil, it combines with mineral salts in the soil to form nitrates which the plants absorb.
Putrefaction: The death of plants and animals releases protein into the soil. These proteins are converted by bacteria into ammonium compounds. The ammonium is therefore converted into nitrite by the genus of Nitrosomonas bacteria, then by those of the genus Nitrobacter into nitrates. The nitrates are absorbed by plants through their roots.

Note:
The bacteria converting protein into ammonia are called putrefying bacteria and the process is known as ammonification, while those converting/oxidizing ammonia to nitrites and nitrates are collectively called nitrifying bacteria and the process is called nitrification.
Application of farmyard manure/organic fertilizers/green manure also add nitrogen into the soil, but at the same time ammonification and nitrification end the reaction.

2. Addition of nitrogen into the atmosphere: This involves conversion of soil nitrates to gaseous nitrogen. This occurs through:
Denitrification: Some bacteria convert ammonia, nitrites or nitrates into free nitrogen which escapes into the atmosphere. This process is called denitrification. Example of denitrifying bacteria include Pseudomonas denitrificans.
Note:
Nitrogen is lost from the soil through the following:
Action of denitrifying bacteria;
Absorption by plant roots;
Action of leaching.


Decomposition in Nature
A decomposer is an organism that breaks down dead organisms or wastes of plants and animals into simpler substances and obtaining energy in the processes. Such organism is a saprophyte and feeds saprophytically i.e. undergoes saprophytic nutrition. Examples include all the fungi (e.g mushroom, Mucor) and some bacteria, others are earthworm, termite.
Classes/types of decomposer:
Micro-decomposers: They are tiny, and cannot be seen with the naked eyes. Examples are certain bacteria and some fungi
Macro-decomposer: they can be easily seen with the naked eyes. Examples are mushrooms, toadstools, mould, termite, earthworms, snails.

Process of Decomposition
The decomposer come on the dead matter/organism; secrete a lytic enzyme which breaks down the complex organic (e.g. proteins and carbohydrates) components into simpler and soluble inorganic (e.g. ammonia gas, hydrogen sulphide gas, carbon dioxide, water vapor and salts like phosphates, sulphate, nitrates, and potassium ions) components/compounds. The salts released are leached into the soil for plants use, while the carbon dioxide released is used for food manufacturing. The decomposer also make use of the nutrients and the energy released in form of heat. When the plant dies, the nutrients absorbed are returned back into the soil and the decomposer re-use it. This use and re-use is called recycling. When the decomposer dies, another decomposer feeds on it and utilize its energy as well for itself and other living organisms e.g. plants.


Roles of Decomposers in Ecosystem
They enrich the soil with nutrients which is used by plants for anabolism.
They cause nuisance and pollute environment when they are present in large numbers.
They are useful in the production of some economic products such as cheese and yoghourt.
They purify the environment through their cleaning activities.
They prevent accumulation of wastes which may be dangerous to our lives.
They maintain a steady supply of useful materials to the producers and the consumers.
Production of fuel e.g. biogas (produced from methane and carbon dioxide formed during decomposition).

EXPERIMENT 3

Aim: To show that carbon dioxide is released during decomposition.
Materials required: two test tubes, delivery tube, decaying humus, lime water.
Method: set-up two experiments; test experiment and control experiment. Label the test experiment as set-up A, while the control experiment is labeled as set-up B. In set-up A, add humus in the test tube as shown below, while in set-up up B, do not add humus. The whole experiment is allowed to stand for about 4-6 hours.
Observation: It is observed that the lime water in set-up A turns milky, while that of set-up B remains the same.
Conclusion: Since the lime water turns milky, it shows that carbon dioxide is released during decomposition.
Note: Hydrogen sulphide (a product of decomposition) can be identified by smell. It smells like a rotten egg.
Assignment.
Describe an experiment to show that heat is released during decomposition.
Construct a detritus food chain.
Discuss the statement: "The movement of energy through an ecosystem is unidirectional but the movement of nutrients is cyclic.

ECOLOGICAL MANAGEMENT

ECOLOGICAL MANAGEMENT
By the end of the lesson, students should be able to:
I. ASSOCIATION:
Recognise some of the different types of association existing between different species.
Identify beneficial harmful and neutral forms of association among organisms.
Deduce the mode of life of a given organism from observed characteristics.
II. TOLERANCE:
Discuss why living things possess a range of tolerance to environmental factors.
 List the abiotic factors that impose tolerance on organisms.
Depict tolerance range with a graph.
III. ADAPTATION:
State that adaptation may be a modification in response to environmental factors.
Describe the availability of water as the principal factor for plant and animal distribution.
List examples of adaptation to environmental factors.
IV. POLLUTION:
Define pollution.
Name air pollutants and their sources.
Enumerate the harmful effects of pollutant.
State effects of detergents, insecticides, artificial fertilizers and herbicides on aquatic and terrestrial organisms.
Identify poor sewage system as a source of pollution.
Name domestic and industrial wastes that pollute land and water.
Identify the decay of organic matter (e.g. dead animals and plants) as a source of pollution.

Biological Association.
This is the food relationship interactions between organisms in an ecosystem, which may be beneficial, neutral or harmful.
Any close and prolonged living together or association of two or more organisms of the same or different species which may be temporary or permanent, harmful, beneficial, or neutral to one or more or all the partners is termed symbiosis.
Types of Symbiosis:
Mutualism;
Parasitism;
Commensalism;
Competition.

Mutualism: A type of relationship in which two different kinds of organisms live together to the benefit of each other. Examples are:
Lichens: This is an association between alga and fungus. The alga provides food for the fungus through its photosynthetic activity, while the fungus provides water through rain water which is
used by alga to photosynthesis its food, it (fungus) also provides for the alga protection against physical damage and drying up.

Mycorrhiza: This is an association between a fungus and the root of a higher plant. The fungi act as root hairs and helps in the transfer of inorganic nutrients from the soil into the plant, while the plant provides the fungus with organic nutrients.
Insect pollinated flowers and insect pollinator: The flower supplies the nectar which the insect feeds upon, while the insect brings about effective reproduction in the plant by pollinating it.

Herbivorous animals and cellulose digesting bacteria in its intestine: These bacteria digest the cellulose of leaves and convert the digested cellulose to sugar which is absorbed by the herbivore, while the herbivore provides shelter and nutrients for the bacteria in the rumens and colon.

Nitrogen fixing bacteria in the root nodules of leguminous plants: The bacteria enter the root of a leguminous plant, causing cell division due to nodules formation, more so, the Rhizobium (the bacterium) fixes nitrogen directly into then plant, and hence, increasing the nitrogen requirement of leguminous plants. While the plant through its root provides nutrients for the growth of the bacteria.

Cattle and tick birds: Tick birds remove blood-sucking flies and ticks from the hides of cattle, in this case, the birds get their food by eating the ticks, while the cattle benefit by having their parasitic infestation reduced.


2. Parasitism: A type of relationship in which two different kinds of organisms live together to the benefit of one (i.e. the parasite) and the detriment of the other (i.e. host). Examples are:

Man and the ascaris/or tapeworm: The ascaris (i.e. roundworm) or tapeworm lives in the small intestine of man where it derives its nutrients, protection and habitat. The man who is the host suffers because he loses to the parasite part of the food he has eaten and digested. This is an example of endoparasitism because the parasite lives inside the body of the host.

Dog and the tick: The tick lives on the surface of the dog where it derives its food (i.e. nutrients) through sucking of the dog blood. The dog who is the host suffers anaemia because he loses to the parasite its blood. This is an example of ectoparasitism because the parasite lives on the outer surface of the host body.

Mistletoe/ or dodder (Cuscuta)/ or witch weed (Striga) and the flowering plant: The mistletoe/or dodder/ or witch weed are parasitic plants that live on flowering plants. The parasite derives support, and also absorbs water and mineral salts  from the flowering plant, while the host loses and harmed by losing to the parasite part of the water and mineral salts that it has absorbed.  This is also an example of ectoparasitism.

Effects of parasite on the host:
It damages the host's tissues.
It kills the host due to damages done to the tissue and due to toxic substances secreted.
Poor growth of the host.
 Discomfort.
 Weakness of the body or structure.
Lack of resistance to diseases.

Parasitic fungi: Some fungi are parasitic to green plants. Examples are:
Ustilago on maize.
Puccinia on maize, wheat or barley.
Phytophthora palmivora on cocoa.
Phytophthora infestans on tomato/potato causing blight
Alternation on tomato.

How parasites (endoparasites) enter the hosts:
Wounds.
Natural openings such as mouth, anus, nostril, ear, eyes in animals and stomata or lenticel in plants.

General adaptation of parasite: A parasite must:

be able to secrete enzymes to dissolve tissues of the host for easy penetration. This is common to endoparasites;
be able to cling or attach to the host's body surfaces (either internally or externally);
have organs that can penetrate through the host's body surface and absorb nutrients. This is common to ectoparasites;
have boring organs which will enable it to enter the body of the host. This is common to endoparasites.

Adaptation of gut parasites e.g. tapeworm, ascaris:

Presence of attachment organs onto the walls of the host gut. Such attachments are hooks and suckers in tapeworm;
ability to respire aerobically or anaerobically;
production of anti-enzymes to neutralize the host's enzymes;
possession of hard cuticles which cannot be digested by host's digestive enzymes;
presence of large surface area to small volume ratio for easy absorption of host's digested food.

How parasitic plants such as Mistletoe and Dodder are adapted to their parasitic life:
They grow on the stem of their host; they penetrate into the host using their sucker; absorb the nutrients from the host; using their sucker called haustoria.

How ectoparasite animals are adapted to their parasitic life:

They have an attachment structures such as claws, suckers and hooks, that enable them to cling to their hosts. Once they attach to the host's body surface, they pierce the host's outer tissues with their modified mouthparts; they suck blood of animals and secrete anti-coagulants to prevent blood clotting or the sap of plants if it is a plant parasite.
Examples of animal ectoparasite that feed on animals are leech, tick, bedbug.
Example of animal ectoparasite that feeds on plants sap is aphids.

Other example of plant parasite is Cassytha.


Assignment:
1. Discuss the life cycle of tapeworms.
2. Differentiate between the following; Tania solium and Tania saginata. Draw and label fully their diagrams.
3. Differentiate in a tabular form, parasitism and saprophytism.

3.    Commensalism: A type of relationship between two organisms of different species in which one of the organisms benefited (i.e. commensal) while the other is neither benefited nor harmed (i.e. host). Examples are:

Remora fish (shark-sucker) and shark: The remora attaches itself to the underside of the shark. The remora feeds on the scraps/left over of shark food. It (remora) also gets protection, and shelter from the shark, whereas the shark is neither harmed nor benefited as a result of the presence of the remora fish.

Oyster and crab: The crab gets shelter/habitation in the oyster shell, whereas the oyster is not harmed.

Epiphyte and a tree: The epiphyte gets a site where it can get enough sunlight to cary out photosyntheses, whereas the tree is not affected.

Dispersal of the fruits of some plants by animals: The fruit of Triumfetta is dispersed by passing animals such as sheep. Triumfetta plant benefits by having its fruits dispersed to a new environment while the animal is not harmed.

Kite and trees: A kite builds its nest on the branches of big trees like Iroko. The tree provides the Kite shelter, whereas the tree does not gain anything from the Kite nor harmed.

Sea cucumber and Fierasfer: The fish called Fierasfer lives in the rectum of sea cucumber. The fish comes out frequently to feed and returns to the rectum by poking the anus of the sea cucumber and enters with its tail. The fish gains shelter and the sea cucumber does not gain nor harmed.

Assignment
Deduce that there is no mutualism neither commensalism that will not lead to parasitism.

4. Competition: This is a type of association between a number of organisms of the same or different species for resources in limited supply such as food, water, space, light, suitable temperature, and mates.

Types of Competition.
There are two types of competition namely:
Intraspecific competition; and
Interspecific competition.

Intraspecific competition: This type of competition involves organisms of the same species. Examples include: planting of flowers or any other plants or crops too close together in a flower bed or space or heap, the plants will compete for space, light, water,  gases, and soil nutrients.

Effect of intraspecific competition: stunted growth and poor flowering and death if not checked. In a nutshell, overcrowding results in intraspecific competition.


How plants and animals have been able to solve problem of intraspecific competition:

To avoid intraspecific competition, overcrowding is solved, hence, plants disperse their spores, seed and fruits by various dispersal mechanism, while animals emigrate, while in human, birth control methods are adopted.

Interspecific competition: This type of competition involves two or more organisms of different species using the same limited resources.
 Effects of interspecific competition:

The stronger competitor may drive the weaker ones into extinction;
One species may enjoy competitive superiority in some regions while the other may be competitively superior in other regions with different environmental conditions.

Examples of interspecific competition include: 1. Two species of duck weeds, Lemma gibba, and Lemma polyrrhiza which grow equally when alone, but L. gibba always replaces L. polyrrhiza when they are grown together. 2. Two species of Paramecium, namely P. caudatum and P. aurelia. 3. Flowering plants and grasses.

The term allelopathy: This is an interaction in which one organism releases a chemical substance(s) into an environment causing a harmful effect on other organisms. For example, the release of chemical substances from the male inflorescence of maize flower inhibits the growth of other grasses near that area while the seed germination of maize is not affected. The maize plant has shown superiority over other plants, hence it will eliminate other plants.

Tolerance.
Tolerance is the ability of a living thing to successfully cope (withstand) with the extreme variations (upper and lower) limits of an environment which affect their survival.
Tolerance Range
This is the range between upper/maximum and lower/minimum limits of abiotic factors affecting the survival of living organisms in a particular area or habitat. Any abiotic factors affecting the organisms below or beyond this limits result in death of the organisms. For example, in most animals, the minimum temperature (i.e. abiotic) limit is 0°C and the maximum limit is 42°C . Their tolerance range is 0°C to 42°C. Anything below 0°C (the lower lethal temperature) and above 42°C (the upper lethal temperature) results to death!

Physiological Stress
 This is a phenomenon which occurs as a result of subjecting an organism beyond its optimum range (the range within which the species' growth and reproduction are at their peaks) which results in a steady fall in its growth and reproductive rate.

Geographic Range
This is the presence of a particular species only in a particular area or geographical region which is within their minimum and maximum limits of their tolerance range.  For example some organisms are limited only to arctic temperate or tropical regions due to temperature factor.

Abiotic factors that impose tolerance on organisms.
Temperature
pH
Soil type
Water//rainfall
Topography/altitude
Pressure
Sunlight/light
Air
Wind
Relative humidity/atmospheric humidity.
Graph showing tolerance range, optimum range and population size.

Adaptation
Adaptation is the ability of an organism to survive and reproduce successfully in any given environment or habitat over a long period of time due to possession of structural, functional or behavioral features.
Plants and animals possess certain features which enable them to adapt to either aquatic or terrestrial habitats.

Adaptation of plants to aquatic environment
Plants that live successfully in water are called hydrophytes. They include Eichornia (water hyacinth), water lily (Nymphaea lotus), Nuphar, red mangrove (Rhizophora racemosa), white mangrove (Avicenna spp.), Raphia palm, Pistia stratiotes(water lettuce), Elodea, Potamogeton, Duckweed ((Lemna) etc.
Adaptation include:
Possession of waxy cuticles on leaves to prevent wetting, e.g. water lettuce.
Possession of long stem and flower stalk to expose the flowers and leaves, e.g. water lily
Possession of air floats in the leaves and stems for buoyancy e.g. water hyacinth
Possession of breathing roots for gaseous exchange e.g. white mangrove
Possession of air spaces in the tissues for buoyancy e.g. water lettuce
Presence of chloroplasts on the leaves and stems                   for photosynthesis/manufacturing of food
Variable leaf shapes to prevent a minimum resistance to water currents and increase the surface area for water and mineral absorption e.g. Potamogeton
Flowers are raised above water for the purpose of pollination

Adaptation of plants to terrestrial environment
Plants living on land can be grouped into two, based on their need for water. These groups include:
Mesophytes: These are plants that live in a moderate condition of water supply (i.e. neither too dry nor too wet), e.g. cashew tree, oil palm tree, maize, yam, cassava, cocoyam, sweet potato
Xerophytes: These are plants that need very small amount of water to live e.g. Desert plants such as Cactus, Euphorbia, Acacia, Aloe, Portulaca.

Adaptation of mesophytes to their environment
Possession of large and flattened leaves to increase gaseous exchange
Possession of waxy cuticle to minimize water loss
Presence of stomata on the leaves for gaseous exchange
Presence of chloroplasts for photosynthesis
Possession of numerous leaves to enhance better photosynthesis
Adaptation of xerophytes to their environment
Presence of succulent stems for water storage e.g. Cacti, Euphorbia, and Opuntia
Presence of succulent leaves to conserve water e.g. Bryophyllum
Possession of deep tap root with extensive lateral roots to source for water e.g. Acacia, Baobab
Leaves are reduced to spine (e.g. in Cactus), or thorns (e.g. in Acacia), or reduced to scale-like structure (e.g. in Casuarina i.e whistling pine) to reduce rate of water loss/transpiration
Possession of thick bark to prevent destruction of parts due to fire outbreak e.g. Baobab
Presence of sunken stomata or lower number of stomata to reduce water loss


Adaptation of animals to terrestrial environment
Possession of hairs, in mammals, feathers in birds and scales in reptiles to regulate body temperature
Presence of lungs for respiration
Presence of sweat glands for excretion and thermoregulation
Presence of skin (e.g. Mammals) and exoskeleton (cuticle) in insects for protection against injury and desiccation
Possession of pairs of limbs to escape predator
Adaptation of animals to aquatic environment
Presence of lateral line to detect vibrations in water, hence adaptation to escape predator
Presence of fins (e.g. Fish) and webbed digits (e.g. Toad) to facilitate swimming
Presence of gills (e.g. Fish) and siphon-like tubes (Mosquito larva) for breathing
Possession of streamlined body to offer minimum resistance to water flowing over them
Presence of suckers or hairs for attachment to vegetation to avoid being swept away by water current e.g. Leech
Possession of nicitating membrane over eye in fishes and presence of eyelids in toads and frogs
Ability to burrow and remain in moist habitats to escape predators e.g. Annelids, clams, and snails

Adaptation of some organisms

Adaptation of toad or frog for food, protection and movement

(A) for food
It possesses special olfactory organ in the head for smelling/perceiving the odometer of its food
It has the ability to draw eyes in so that they make bulges in the root of the mouth which help to prevent their prey from escaping and help in swallowing
The tongue is attached at the front of the mouth which can be rapidly extended to capture/trap prey
The tongue is long and sticky to help hold the prey.

(B) for protection
The skin is slimy with mucous gland which makes the animal difficult to be caught by predators
Slimy fluid keeps the skin moist and prevents the skin from drying up
Toad  has poison glands on the skin which is poisonous and distasteful to the predators
Cryptic coloration to prevent them from being noticed by enemies and predators
The colour can be altered to match the type of background.

(C) for movement
Presence of powerful muscular hind limb to hop/jump, hence escape predators
Absence of tail facilitates hopping or jumping movement
Webbed hind limb can be used as paddle for efficient swimming in water
The stout and short nature of fore limb absorbs shock on landing and for propping up the front end of the body on landing after a jump or hop
Presence of streamlined body for easy movement and swimming
Adaptation of chameleon/lizard
Possession of long, sticky tongue for capturing preys
Possession of claws on the feet for holding objects on which it walks
Possession of powerful eyes to see preys and predators easily
Possession of scales to prevent desiccation
In chameleon, there is ability to change the colour of the body in order to hide from its predators.

Assignment
Discuss the adaptation of the following organisms to their environment:
Endoparasite e.g. Tapeworm
Tilapia fish
Tadpole