BIOLOGY 3 Marks Question

Plastic containers, paper, electronic goods, left over food, food package, disposable glasses, cup plates, polythenes, excreta, soap and detergent waste are the wastes that one can generate at home, school or during trips to other places. Yes, we can easily reduce waste through judicious use of material by changing our habits & life styles.
Out of these, polythene and plastic material are hard to dispose off as they are non- biodegradable and they can be recycled back.

Eutrophication: It is excessive growth of algae, plants and animals in water bodies due to the nutrient enrichment particularly with nitrogen and phosphorus. It is both natural and accelerated. It leads to loss of bio-diversity and cuases chemical accumulation in food chain and ageing of water body.

Ground water depletion and replacement: Ground water depletion, a term often defined as long term water level declines caused by sustained ground water pumping, is a key issue associated with ground water use. Many areas of India experiencing ground water depletion.
The most servere consequence of excessive ground water pumping is that the water table, below which the ground is saturated - with water, can be lowered. If ground water level declines too far, then the well owner might have to deepen the well, drill a new well, or at least attempt to lower the pump.

1. Any discarded material that emits radiations is called radioactive waste. Radiations, emitted by nuclear waste is extremely damaging to biological organisms. It causes mutations to occur at a very high rate, resulting in various disorders like cancer. At high doses, nuclear radiation is lethal. The Defunct ships are dead ships that are no longer in use. Such ships are broken down for scrap metal in countries such as India and Pakistan. These ships are a source of various toxicants such as asbestos, lead, mercury etc. Thus, they contribute to solid wastes that are hazardous to health.
2. Defunct ships are dead ships that are no longer in use. Such ships are broken down for scrap metal in countries such as India and Pakistan. These ships are a source of various toxicants such as asbestos, lead, mercury etc. Thus, they contribute to solid wastes that are hazardous to health. E-wastes or electronic wastes generally include electronic goods such as computers etc. Such wastes are rich in metals such as copper, iron, silicon, gold etc. These metals are highly toxic and pose serious health hazards. People of developing countries are involved in the recycling process of these metals and therefore, get exposed to toxic substances present in these wastes.
3. Municipal wastes includes homes, offices, schools, hospitals etc. It is collected and disposed off by the municipality. These generally consists of paper, leather textile, rubber, glass, etc. Sanitary landfills are used to dump these wastes.

Women and communities have played a major role in environmental conservation movements.

• Case study of the bishnoi community: he Bishnoi community in Rajasthan strictly believes in the concept of living peacefully with nature. In 1731, the king of Jodbpur ordered his ministers to arrange wood for the construction of his new palace. For this purpose, the minister and the workers went to bishnoi village. There, a Bishnoi woman called Amrita Devi along with her daughter and hundreds of other Bishnois showed the courage to step forward and stop them from cutting trees. They embraced the trees and lost their lives at the hands of soldiers of the king. This resistance by the people of the village forced the king to give up the idea of cutting trees.
• Chipko movement: The Chipko movement was started in 1974 in the Garhwal region of the Himalayas. In this movement, the women from the village stopped the contractors from cutting forest trees by embracing them.

Biological magnification: Increase in concentration of persistent chemical at successive trophic levels is called eutrophication. This happens because a toxic substance accumulated by an organism can not be metabolized or excreted, and is thus passed onto next trophic level, e.g., DDT.

1. Natural ageing of lake is called as eutrophication. Its caused due to gradual accumulation of organic matter over a period of time.
2. Due to uncontrolled human activities like deposition of waste into the water bodies, there is an increase in the organic matter. Thus polluting the water.
3. The human activities accelerated the accumulation of organic matter, thus resulting is early aging of lake which is known as accelerated eutrophication.

1. What the villagers saw and are delighted about is algal bloom over a stationary water body. This algal bloom will cut off the supply of light and oxygen to the submerged flora and fauna of the water body. It will outcompete the water bodies flora and fauna for nutrients and will rapidly grow and deplete other organisms in the given water body ecosystem of necessary nutrients. This will quickly lead to the death, decay and destruction of the already existing water body ecosystem.
2. The flushed out and washed nutrients from the excess fertilisers of the nearby fields had accumulated and promoted the sudden burst in the growth of algal bloom on the water body. This phenomenon is often termed as Cultural or Accelerated Eutrophication.

Effects of sewage discharge on river are:

1. A sharp decline in dissolved oxygen and increase in BOD. Low oxygen levels in the water cause death of fish and other aquatic creatures.
2. Algal bloom which results from the presence of organic matter in water.

It causes:

1. Deterioration of the water quality.
2. Fish mortality.
3. Toxicity to humans and animals.

3. Biological magnification of a few toxic substances, as DDT causing harmful effects in living species.
4. Accelerated eutrophication, i.e. ageing of lakes and other water bodies due to human activities.

Rapid deforestation, massive burning of fossil fuel, have significantly increased the rate of release of carbon dioxide, polluting atmosphere, this green house gas, contributes to global warming.

Enrichment of water body by excessive nutrients is known as eutrophication.
The events of eutrophication are as follows:

High BOD of a water body indicates more number of micro-organisms in water, resulting in bad quality of water/death of aquatic creatures, more polluting potential.
Lower BOD of water body indicates less number of micro-organisms in water, good quality of water/aquatic life flourishes, less polluting potential.

1. A - algae/planktonic (free floating) algae.

B - fish/aquatic animals.

2. Due to excessive loading of nutrients/fertilizers from adjacent agriculture land resulting in increase in nutrients.
3. Decrease in dissolved oxygen (DO), increase in BOD, fish mortality, unpleasant odour/eutrophication.

An algal bloom is the phenomenon of excessive growth of planktonic forms in a nutrient rich water body. As the planktonic species multiply on the surface they form a layer that eventually covers the entire surface of the water body.
They block sunlight, which does not reached submerged aquatic plants that may have a role in supplying necessary nutrients to other aquatic life forms and keeping the water clean. Some algal species can release toxic substances.
Due to the high respiratory needs of such a huge concentration of biomass on the surface, the biological oxygen demand (BOD) of the water body increases, causing many of the life forms to die, their carcasses further contribute to the deterioration of the quality of the water content.

CNG/Compressed Natural Gas.
It burns more efficiently unlike diesel or petrol, very little of it is left unburnt, cannot be adultered, cheaper than petrol or diesel.

1. Particulate matter will pollute the air.
2. Use of CNG/Phasing out of old vehicles/Use of unleaded petrol/Use of low sulphur fuel/Use of catalytic converters/Application of stringent pollution level norms.

1. a = conformers.
2. Response of the regulators.
3. Maintain homoeostasis by physiological means, others either migrate or suspend activities.
4. Regulators.

1. Emission of greenhouse gases, absorb IR radiation from earth’s surface/emit it again to earth, the cycle continues, till the earth’s surface has no long wave radiations to emit.
2. Deleterious changes in the environment, odd climatic changes, melting of polar/Himalayan ice caps, rise in sea level, flooding/submerging of coastal areas.

Toxicants like DDT entered the trophic levels of the food chain, accumulated as it can neither be metabolised nor be excreted, toxicants disturb Ca metabolism, result in thinning of egg shells, premature breaking of eggs, population declined.

Use of CNG as the fuel, use of unleaded petrol, low-sulphur petrol/diesel, use of catalytic converter in the vehicles, phasing out of old vehicles.

1. Increase in level of greenhouse gases, molecules of these gases do not allow the infrared radiation of the earth to escape into space; this heat is radiated back, causing global warming.
2. Consequences - Polar ice caps and glaciers will melt, rise in sea level, mutation of DNA.

Biological magnification: The phenomenon through which certain pollutants get accumulated in tissues in increasing concentrations, along the food chain.DDT concentration increases in the phytoplankton relative to the concentration in water, zooplankton contained greater DDT than phytoplankton, in different fish the DDT concentration increased relative to the concentration in zooplankton, birds showed greater DDT concentration relative to that in fish.

Eutrophication: Process of nutrient enrichment of water, and consequent loss of species diversity.Consequences: Excess nutrients cause profuse growth of algae (algal bloom)/ blue-green algae causing oxygen deficiency in water.
Aquatic animals (e.g., fish) may die due to toxicity/ lack of oxygen.
Because photosynthesis which oxygenates the water ceases at night.

It. has electrode wires maintained at a very high voltage which produce a corona that releases electrons.

These electrons get attached to the dust particles and gives them a net negative charge. The collecting plates are grounded to attract the negatively charged dust particles' Thus, when the air passes through the collecting plate, it gets cleaned. Velocity of air between the-plares.is maintained at low value to allow the dust to fall on the collecting plate.

1. A: Planktonic algae, Decomposers

B: Fish, other aquatic animals.

2. Presence of large amount of nutrients like nitrogen and phosphorus.
3.  

• The growth of planktonic algae (algal bloom) causes deterioration of water quality and fish mortality.
• The decomposers acting on the dead plants and animals (organic matter) consume a lot of oxygen (increased BOD) and this causes mortality of fish and other aquatic animals.

1. BOD-Biochemical Oxygen Demand.
2. It indicates the addition of lot of organic matter; microorganisms involved in the biodegradation of organic matter in the water body consume a lot of oxygen and as a result, there is a sharp decline in the dissolved oxygen content downstream from the point of addition of effluent from the factory. This causes mortality of fish and other aquatic organisms.
3. When the amount of organic matter decreases and the microbes do not need oxygen for decomposition, the BOD decreases. Thus, aquatic organisms will start flourishing.

Multipurpose trees are that which are grown for more than one purpose or benefits. They may provide food in the form of fruit, seeds, or roots; and also provides firewood, medicines, fibres, etc.

1. Neem (Azadirachta indicd): Used as insect repellent, antibiotic, firewood and windbreaks.
2. Coconut palm (Cocos nucifera): Used for food, purified water (juice from inside the coconut), roof thatching, firewood, shade and rope making.

1. Yes, it is True.
2. Two applications of solar energy are; using solar cells to produce electricity, using solar cooker to cook food, using solar heater for hot water.
3. A cell which converts solar energy into electric energy is known as photovoltaic cell.

• BOD is the amount of oxygen required by the decomposer micro-organisms for decomposing the organic matter in the water.
• Higher the BOD, higher is the quantity of organic matter in the water body.
• If more organic matter is there, the microbes also flourish in the water body and increase their number.

1. It indicates that the sugar factory releases organic waste in the water body. To degrade the organic matter, microbes utilise the dissolved oxygen in the water, thereby, reducing the levels of dissolved oxygen and increasing the BOD.
2. In this part of river, the dissolved oxygen will be depleted making it difficult for aquatic species to survive. It can result in death of fishes in severe cases.

1. A-algae/ planktonic (free floating) algae.

2. Due to excessive loading of nutrients or fertilisers from adjacent agricultural land results increase in nutrients.
3. Effects: decrease in dissolved oxygen (DO), increase in BOD, fish mortality, unpleasant odour/ eutrophication.

S. No.	Biological Oxygen Demand (BOD)	Chemical Oxygen Demand (COD)
(i)	It is the amount of oxygen required for microbial breakdown of organic matter.	It is the amount of oxygen required for oxidation of both biodegradable and non-biodegradable organic matter in the water.
(ii)	Its value is less than COD.	Its value is more than BOD.

Higher biological oxygen demand shows that the dissolved oxygen in water bodies is much reduced and thus aquatic animals will die.

1. The management of non-biodegradable waste is of great concern as comparison to biodegradable waste because non biodegradable waste cannot be degraded by microbes and get accumulated in the environment. Biodegradable waste can be degraded by microbes into simpler form in which it can be used in ecosystem.
2. Two ways to organise 'zero garbage day' is as follows

1. Tell them about 'zero garbage day'.
2. Remind them rules to organise the day and also telling them importance of this day.

Trees and shrubs are effective in reducing noise level. Planting trees and shrubs near the boundary walls of buildings helps in reducing noise level and act as dust catchers. Such a line of trees along the boundary or along the roadside is also called sound barrier.

The word hybrid itself suggests the combination of two. Hybrid Vehicle technology is the technology which allows the vehicle to run on dual mode like petrol and CNG.Advantages of hybrid vehicle technology:

• As CNG is a green fuel, the fossil fuels are conserved.
• Reduction in environmental pollution.
• CNG is cheaper than petrol and diesel.
• CNG can’t be adulterated like petrol or diesel.

Six harmful effects of noise on human population are:

1. Sleeplessness.
2. Stress.
3. Increased rate of heartbeat and hypertension.
4. Breathing problems.
5. Damage of ear drums impairing hearing ability permanently.
6. Gastric problems-nausea.
7. Emotional disturbance

After green revolution, the use of inorganic fertilisers, etc., has increased to enhance the crop productivity. Pesticides, fungicides, herbicides are being increasingly used to serve this Purpose.
These chemical substances are toxic to non-target organisms and also pollute the soil and water bodies. They cause problems like eutrophication, biomagnification and soil pollution.

Snow-blindness is also known as photokeratitis. It happens because of exposure of eyes to UV-B radiation. Burning sensation, pain and increased tears are common symptoms of snow-blindness. The person suffering from snow-blindness feels that his eyes are full of sand.

1. With the rapid development of technology, as more and more electronic products are produced which is driving the ever-increasing production of e-wastes,
2. Following point can be explained to students to address the awareness issues.

1. Appropriate use of information technology equipment.
2. Safe disposal of e-waste.

3. Developed countries have exploited the developing countries with respect to e-waste managements. The information technology is more advanced in developed countries. They produce many equipment and export them to developing countries that leads to enormous collection of e-wastes in that countries.

1. The pattern A is depicted by microorganisms and pattern B is depicted by fishes or any other aquatic organism.
2. As the lake is adjacent to an agricultural land extensively supplied with fertilisers, the run-off water from the field will result in increase in nutrients of lake. Thus, number of microorganisms will rise to degrade organic matter.

Realising the significance of participation by local communities, the Government of India in 1980s has introduced the concept of Joint Forest Management (JFM) so as to work closely with “the local communities for protecting and managing forests. In return for their services to the forest, the communities get benefit of various forest products (e.g., fruits, gum, rubber, medicine, etc.), and thus the forest can be conserved in a sustainable manner.