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Kerala Plus Two Botany Chapter Wise Questions and Answers Chapter 8 Environmental Issues

Plus Two Botany Environmental Issues One Mark Questions and Answers

Question 1.
CPCB stand for
(a) Central pollution consistent board
(b) Central particulate collection & analysis board
(c) Central pollution Control Board
(d) Central phenomenon coexisting Board (pollution)
Answer:
(c) Central pollution Control Board

Question 2.
Catalytic converters may contain expensive metals like……….as catalytic in automobiles
(a) Platinum
(b) Palladium
(c) Rhodium
(d) All of these
Answer:
(d) All of these

Question 3.
The participation of local communities helps to conserve the forest in sustainable manner. Name the recently started project of Govt, of India.
Answer:
In 1980s Government of India has introduced the concept of Joint Forest Management (JFM).

Question 4.
According to the Central Pollution Control Board, particles that are responsible for causing great harm to human health are of diameter:
(a) 2.50 micrometers
(b) 5.00 micrometers
(c) 10.00 micrometers
(d) 7.5 micrometers
Answer:
(a) 2.50 micrometers

Question 5.
Match the items in column I and column II and choose the correct option:

(a) A-ii, B-i, C-iv, D-iii
(b) A-iii, B-ii, C-iv, D-i
(c) A-iii, B-iv, C-i, D-ii
(d) A-iii, B-i, C-iv, D-i
Answer:
(c) A-iii, B-iv, C-i, D-ii

Question 6.
Three-mile Island, Chernobyl incidents are typical example for………pollution
(a) Sound
(b) Radioactivity
(c) Water
(d) Physical
Answer:
(b) Radioactivity

Question 7.
Match correctly the following and choose the correct option

The correct matches is:
(a) i-C, ii-D, iii-A, iv-B
(b) i-A, ii-C, iii-B, iv-D
(c) i-D, ii-A, iii-B, iv-C
(d) i-C, ii-D, iii-B. iv-A
Answer:
(a) i-C, ii-D, iii-A, iv-B

Question 8.
Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unbumt hydrocarbons into:

(a) carbon dioxide and water
(b) carbon mono oxide
(c) methane
(d) carbon dioxide and methane
Answer:
(a) carbon dioxide and water

Question 9.
In the modern world there are different types of substance that may cause pollution. A prominent waste in the modern computer world is “e-waste” The “e-waste” stand for
(a) Eliminated waste
(b) Eroded waste
(c) Electronic waste
(d) Enriched waste
Answer:
(c) Electronic waste

Question 10.
Humans, as well as other animals, have been dumping their wastes into the environment for thousands of years. What is the reason that this appears to be such a problem today?
Answer:
The human population is increasing rapidly, produc-ing more wastes, and a significant amount of the wastes are non-biodegradable.

Question 11.
Air pollution is maximally caused by
(a) Household detergents and pesticides
(b) Automobile exhausts and chemicals from industry
(c) Sewage and pesticides
(d) Sewage and industrial effluents
Answer:
(b) Automobile exhausts and chemicals from industry

Question 12.
Observe the figure given below. Identify the equipment and write its use.

Answer:
Scrubber: A Scrubber can remove gases like sulphur dioxide.

Question 13.
Government of India has instituted an award for individuals or communities from rural areas who have shown extraordinary courage and dedication in protecting wild life. Name that award.
Answer:
Amrita Devi Bishnoi Wildlife Protection Award.

Question 14.
Ecological sanitation is a sustainable system of handling human excreta, using dry composting toilets. Write the advantages of this method.
Answer:
It is Hygienic .efficient, cost effective and human excreta can be recycled into a natural fertilizer.

Question 15.
Choose the correct answer. Substances that cause biomagnification are
(a) Mercury and DDT
(b) Mercury and Phosphorus
(c) DDT and Phosphorus
(d) Phosphorus and nitrogen
Answer:
(a) Mercury and DDT

Question 16.
Observe the relationship between the first two terms and fill in the blank. Green house effect: carbon dioxide; ozone depletion:…………..
Answer:
Chlonofluorocarbons.

Question 17.
Choose the correct statement regarding biomagnification in an aquatic ecosystem.
(a) Decrease in concentration of the toxicant in successive tropic levels.
(b) Higher concentration of toxicant is seen in the first trophic level.
(c) Bird population is least affected.
(d) Causes decline in bird population.
Answer:
(d) Causes decline in bird population.

Question 18.
In 1986 Govt, of India passed Environment Act. Write the purpose of its implementation.
Answer:
To protect and improve the quality of our environment (air, water, and soil).

Question 19.
The participation of local communities helps to conserve the forest in sustainable manner. Name the recently started project of Govt, of India.
Answer:
In 1980s Government of India has introduced the concept of Joint Forest Management (JFM).

Question 20.
Give the term for reradiating of heat radiations by atmosphere dust, water vapours, CO-₂ CH-₄, O₂, etc.
Answer:
Green house effect

Question 21.
How CFCS cause the depletion of Ozone shield?
Answer:
By producing active chlorine which breaks ozone.

Plus Two Botany Environmental Issues Two Mark Questions and Answers

Question 1.
Expand CPCB – Write its significance.
Answer:
CPCB – Central Pollution Control Board.
CPCB – Aims for controlling particulate matter in the air. According to CPCB the particulate size 2.5 micrometers or less than in diameter (PM 2.5) are responsible for causing greatest harm to human health.

Question 2.
Working condition of electrostatic precipitator is given. By analysing the figure explain the process.

Answer:
At high voltage the electrons produced are attached to dust particles giving them a net negative charge. These charged dust particles are attracted by collecting plates. Then reducing the velocity of air between the plates which help the dust to fall.

Question 3.
Pollutant free Metropolitan cities can be raised by the use of CNG.

1. Expand CNG?
2. What are the?

Answer:
1. CNG is compressed natural gas.

2. advantages of CNG:

• CNG is better than diesel
• It burns most efficiently
• CNG is cheaper than petrol or diesel
• It cannot be adulterated like petrol or diesel.

Question 4.
Montreal protocol is a procedure signed at Montreal (Canada) in 1987.

1. Identify the environmental issue related to this.
2. Which is the chemical causing the environmental problem?

Answer:

1. Ozone hole
2. Chloro fluro carbons release active chlorine atoms which results in degradation of the ozone in the stratosphere.

Question 5.
“Pollutant free Metroes” – Can this be achieved in future?

OR

Pollutant free Metropolitan cities can be raised by the use of CNG. What does CNG implies? Can you suggest the priorities and limitations of CNG?

Answer:
CNG is compressed natural gas. It burns more efficiently than Petrol and diesel, thus brings down the amount of pollutants from automobiles (unburnt hydrocarbons).

CNG is cheaper than petrol or diesel. It cannot be siphoned out by thieves and adultered like petrol or diesel.

The problem in using CNG as fuel is the difficulty of laying down pipelines to deliver CNG through distribution points.

Question 6.
If motor vehicles are equipped with catalytic converter the pollution rate can be reduced.

1. Give reason.
2. Catalytic converters have its limitations. Mention the limitations.

Answer:
1. Catalytic converters are used in motor vehicles to reduce pollutants. Catalytic converters convert unburnt hydrocarbons into CO₂ and water. The catalytic converter uses expensive metals like Platinum, Palladium or rhodium as catalysts.

2. These catalysts are inactivated if leaded petrol is used.

Question 7.
Particulate and gaseous pollutants along with harmless gases are released from the thermal power plants.

1. Name any two harmless gases released.
2. Name the most widely used device of removing particulate pollutants from the air. Explain how the device is used.

Answer:
1. NO₂ & O₂.

2. Electrostatic precipitator
It has electrodes which are maintained at several 1000 watts which releases electrons. These electron attach to dust particle giving them a net -ve charge. The collecting plates attract the charged dust particle. The velocity of air between the plates are lowered to allow dust to fall.

Question 8.
Higher BOD could lower the D.O.

1. Do you agree with the statement.
2. Give reason.

Answer:
1. Yes.

2. Higher BOD lower the D.O. content of water. D.O. is the dissolved 02 content of water. When organic content is increased in water the D.O. is consumed for its oxidation by bacteria which is referred as BOD (Biochemical Oxygen demand) when B.O.D. is greater the D.O. becomes low.

Question 9.
Pesticide DDT was used to control insect such as mosquitoes and agricultural pests. But DDT persisted in the environment and transported from one trophic level to higher trophic levels.

1. Name the phenomenon and explain it.
2. What happens to the concentration of DDT in each trophic level?

Answer:
1. Biomagnification.
Biomagnification refers to increase in concentration of the toxicant at successive trophic levels.

2. Non biodegradable toxic substance accumulated by an organism cannot be metabolised or excreted and it is passed to the next higher trophic level.

Question 10.
Sewage from common hospitals if disposed to water bodies may cause the outbreak of serious water-borne diseases.

1. Mention 2 water-borne diseases.
2. Which is the popular method used to remove hospital waste?

Answer:

1. Dysentry, typhoid, jaundice, etc.
2. Incineration

Question 11.
Match the following.

Answer:

1. Catalytic converters – Air pollution
2. Polyblend – Plastic wastes
3. Organic farming – Agro chemicals
4. Sanitary land fills – Solid wastes

Question 12.
Solid waste can create a major problems in metro cities.

1. Which is the best way for the safe disposal of the solid waste
2. Classify solid waste into 3 groups, which is the alternative remedy for the use of plastic

Answer:
1. Sanitary land fills.

2. The Solid wastes can be categorised into 3 types

• bio degradable
• Recyclable
• non-biodegradable.

The biodegradable waste material can be disposed in deep pits for natural break down. Recycling of material is made easy by the separation done by rag pickers.

Non-biodegradable waste should reduced by using eco-friendly packaging & natural fiber carry bags. State government can play important role by applying laws for reducing the use of plastics.

Question 13.
Integrated organic farming is a zero waste procedure.

1. Do you agree with the statement.
2. Give reason.

Answer:
1. Yes.

2. Integrated organic farming is a cyclical zero waste procedure, where waste products from one process are cycled and act as nutrients for other processes. This allows the maximum utilization of resources and increases the efficiency of production.

For example if dung is used as manure for the crop, the crop waste can be used to create compost which in turn can be used as fertilizer after generating energy needs of the farm.

Question 14.
Analyse the situation given below and comment on it. “Fertilizers from a paddy field flows to nearby pond.’’
Answer:
Presence of large-amount of nutrients caused by sewage disposal causes excessive growth of planktonic algae which imparts distinct color & decreases quality of water & increases mortality of fishes.

Question 15.
Rag pickers do a great job for our nation. Justify this statement.
Answer:
The Solid wastes can be categories into 3 types

• biodegradable
• Recyclable
• non-biodegradable.

The biodegradable waste material can be disposed in deep pits for natural break down. Recycling of material is made easy by the separation done by rag pickers.

Question 16.
Ecologist argued that organic fertilizers are better for the soil than the chemical fertilizers, (hint – organic fertilizers:- green manures, cattle dung, biofertilizers). Write your opinions.
Answer:
Organic fertilizers are better for the soil as they do not cause pollution of soil and water. Chemical fertilizers which drained into the water bodies will cause eutrophication and algal blooms.

They also cause increase in BOD and lead to the destruction aquatic flora & fauna. Organic fertilizers are cheaper they tend to remain in the soil for long period.

Question 17.
Ahmed khan in Bangalore proved himself a good citizen in using his talents in solving a social issue. Comment on his contribution.
Answer:
Ahamed khan in Bangalore who is a plastic sac manufacturer effectively use poly blend – a fine powder produced from recycled plastic & mixed it with bitumen that is used to lay roads.

By doing so he could enhance the water repellent property of bitumen & which in turn help to road life by three times. It also reduced pollution caused by plasticis. It is an example for the effective way for recycling non biodegradable – plastic.

Question 18.
The concentration of DDT like toxins are higher in man and eagle.

1. Name the process.
2. Give the reason

Answer:
1. Biomagnification

2. Non bio degradable chemical which accumulate in the body of organism and is passed on to the organisms belonging to the next trophic level. Human beings & Eagle belong to the last trophic level of the food chain. Hence the bio magnification threaten human life.

Question 19.

1. Identify the process
2. Find out the reason for these.

Answer:
1. Biomagnification.

2. The concentration of DDT is increased at successive trophic levels. It starts at 0.003 ppm in water, it can ultimately can reach 25 ppm in fish-eating birds, through biomagnification.

High concentrations of DDT disturb calcium metabolism in birds, which causes the thinning of eggshell and their premature breaking, causing decrease in bird populations.

Question 20.
Integrated organic farming is a zero waste procedure. Do you agree with the statement. Justify.
Answer:
Yes. Integrated organic farming is a cyclical zero waste procedure, where waste products from one process are cycled and act as nutrients for other processes. This allows the maximum utilization of resources and increases the efficiency of production.

Question 21.
Solid waste can create a major problems in metro cities.

1. Which is the best way for the safe disposal of the solid waste
2. Classify solid waste into 3 groups, which is the alternative remedy for the use of plastic

Answer:
1. Sanitary land fills

2. The Solid wastes can be categorised into 3 types

• biodegradable
• Recyclable
• non-biodegradable.

Non-biodegradable waste should reduced by using eco-friendly packaging & natural fiber carry bags.

Question 22.
Ahmed khan in Bangalore proved himself a good citizen in using his talents in solving a social issue. Comment on his contribution.
Answer:

• Ahmed Khan in Bangalore has found a solution for problem of accumulating plastic waste.
• Polyblend, a fine powder of recycled modified plastic, is mixed with the bitumen that is used to lay roads.
• Bitumen is a water repellant substance helps to increase road life.
• The raw material for creating Polyblend is any plastic film waste that brought about by rag pickers.

Question 23.
In north- eastern state of India major hectors of Forest land is degraded by a mode of cultivation.

1. Name the cultivation method
2. Explain the procedure of this cultivation

Answer:
1. Jhum cultivation.

2. In Jhum cultivation or slash & burn cultivation, forest land is converted to agricultural land by cutting and burning trees, ash obtained is used as fertilizer for crop cultivation and other land is used for grazing cattle. The process repeated and it leads to deforestation.

Question 24.
What are Euro II norms?
Answer:

1. Sulphur be controlled at 350 ppm in diesel and 150 ppm in the petrol.
2. Aromatic hydrocarbons are to be contained at 42% of concerned fuel.

Question 25.
It has been recorded that the temperature of the earth’s atmosphere has increased by 0.6°C.

1. What has caused this increase?
2. Explain its consequences.

Answer:
1. Increase in the level of green house gases causes global warming.

2. Its consequences:

• Polar ice caps and glaciers will melt
• rise in sea level

Question 26.
Air pollution causes serious health problems in men, in industries ECP is a fitted in place of exhaust coming from smokestack to control pollution.

1. Which is the device used to control Sulphur Dioxide pollution?
2. Name the agency of Government of India monitor air pollution.

Answer:

1. Scrubber
2. CPCB (Central pollution control board)

Question 27.
Higher concentration of DDT is found in third trophic level than first trophic level

1. Name the phenomenon associated with the accumulation of DDT
2. Bird population is decreased by the accumulation of DDT. How is it occurs?

Answer:

1. biomagnification
2. DDT affects the calcium metabolism of birds, causes the thinning of egg shell and premature breaking that it result the reduction in bird population.

Question 28.
Many low lying land become submerged in coming centuries due to the increasing temperature of atmosphere

1. Name two greenhouse gases causes global warming
2. Write down the measures to reduce the emission of greenhouse gases

Answer:
1. Carbon dioxide and chioro fluoro carbon

2. Measures to reduce the emission of greenhouse gases:

• Cutting down the use of fossil fuels
• Reduce deforestation activities.

Question 29.
Plastic film waste that is used to made modified recycle plastic by Ajmal Khan in collaboration with RV College of Engineering

1. Name the product formed after the recycling of film waste
2. Name the water repellent substances is mixed with modified a plastic to lay down Road in Bangalore city Corporation

Answer:

1. Polyblend
2. Bitumen

Question 30.
There is a balance between production and degeneration of ozone in the stratosphere.

1. Name the gas that disturbs this balance.
2. Explain how this balance is disrupted?

Answer:

1. Chlorofluorocarbons (CFCs)
2. In stratosphere ,UV rays act on CFCs and release active Cl atoms, that degrades ozone releasing molecular oxygen.

Question 31.
The amount of biodegradable organic matter in sewage water can be estimated by measuring BOD.

1. Expand BOD
2. Write the impact of the discharge of sewage into a river

Answer:

1. BOD – Biochemical Oxygen Demand
2. Polluted water contains microorganisms they consume lot of oxygen from water for the biodegradation of organic material that Causes sharp decline in dissolved oxygen.

Question 32.
Radiation by nuclear waste is extremely dangerous to organisms.

1. Write any two dangers.
2. Write the recommendations for the storage of nuclear waste.

Answer:

1. Causes mutation at a very high rate At high doses nuclear radiation is lethal
2. Nuclear waste must be stored after sufficient pre-treatment. It must be done in suitable shielded containers buried within the rocks, about 500m deep below the earth’s surface.

Question 33.
There is a balance between production and degeneration of ozone in the stratosphere.

1. Name the gas that disturbs this balance.
2. Explain how this balance is disrupted?

Answer:

1. Chlorofluorocarbons (CFCs)
2. In stratosphere, UV rays act on CFCs and release active Cl atoms, which degrades ozone releasing molecular oxygen.

Question 34.
Algal bloom and eutrophication are the two effects of water pollution. Write the differences between the two.
Answer:
1. Algal bloom:
Excessive growth of planktonic algae due to the presence of large amount of nutrients in water.

2. Eutrophication: Natural aging of a lake by nutrient enrichment of its water.

Question 35.
Match the items of column A with B.

Answer:

Question 36.
A number of human activities contribute to deforestation.

1. Write any one such activity.
2. Write the consequences of deforestation.

Answer:
1. Cutting trees for timber and firewood.

2. consequences of deforestation:

• Increase carbon dioxide concentration in the atmosphere
• Loss of biodiversity due to habitat destruction
• Disturbs hydrologic cycle
• Causes soil erosion

Question 37.
In 1980s the Government of India has introduced JFM to conserve forests.

1. Expand JFM.
2. Write its significance.

Answer:

1. Joint Forest Management.
2. Participation by local communities for protecting and managing forest and these communities get benefit of various forest products.

Question 38.
Catalytic converters are fitted into automobiles for reducing emission of poisonous gases into the atmosphere. Write its working in reducing pollution.
Answer:
As the exhaust from the automobiles passes through the catalytic converter, hydrocarbons are converted into harmless carbon dioxide and water. Carbon monoxide is changed into carbon dioxide.

Plus Two Botany Environmental Issues Three Mark Questions and Answers

Question 1.
As a part of project work, a group of students collected water samples from different locations. Water samples and its BOD contents are given below.

1. Analyse the data given below and find out the sample which is highly polluted.
2. Give reason. Expand BOD.

Answer:

1. Sample. A is highly polluted.
2. BOD (Biochemical Oxygen demand).- refers to the amount of O₂ that is consumed when organic matter is oxidised by bacteria. If greater the BOD of water, the rate of pollution is high.

Question 2.
Global warming leads to so many hazards in the environment.

1. What are the green house gases?
2. How does it leads to global warming
3. Suggest any three methods to control it.

Answer:
1. Green house gases- CFC, N₂O, CH₄, CO.

2. In the atmosphere green house gases causes re radiation of infrared radiation & results in the over heating of earth. This is called global warming. Global warming causes changes in the climate Eg. EL Nino effect, Increased melting of polar ice caps rise in sea levels & submerging of coastal areas.

3. Suggest any three methods to control it:

• Cutting down the use of fossil fuel,
• Improving efficiency of energy usage,
• Reducing deforestation, planting trees

Question 3.
Ramu is comparing the graph given in the magazine and recognized that the content of aromatic hydrocarbons, CO, and NOx were decreased from 1997 to 2006 period. Give the reason of your findings.
Answer:
The new auto fuel policy introduced by the government of India is to reduce the sulphur,carbon monoxide and aromatics content in petrol and diesel fuels. The above mentioned things can be put in practice by different engine norms.

1. Bharat Stage II (equivalent to Euro-llnorms)
2. Euro III emission specifications
3. Euro-IV

Question 4.
A factory drains its waste water into the nearby lake. It has caused algal bloom.

1. How was the algal bloom caused?
2. What would be the consequences?
3. Name the phenomenon that caused it?

Answer:

1. Nutrients of waste water causes extensive growth of planktonic algae or free floating algae (algal bloom).
2. Algae use oxygen .biochemical oxygen demand go high, high fish mortality, deterioration of water quality.
3. Eutrophication.

Question 5.
The existence of human beings is under great threat due to the uncontrolled emission of green house gases. Can you suggest any 2 remedial measures to reduce this effect?
Answer:
The emission of green house gases can be reduced by cutting down use of fossil fuel, improving the efficiency of energy usage, reducing deforestation planting trees & slows down the growth of human population.

Question 6.
The balance between the formation and degradation of ozone disrupt due to the overuse of chloro fluoro carbons.

1. Name the degraded product of chlorofluorocarbon causes of ozone depletion
2. Which is the unit used to measure ozone thickness in stratosphere
3. Give two diseases affects men due to ozone depletion

Answer:
1. Active chlorine
2. Dobson (Du)
3. Two diseases affects men due to ozone depletion:

• snow blindness
• cataract

Question 7.
In Kerala, the major source of atmospheric pollution comes from automobile sector.

1. Expand CNG
2. State some novel practical steps to minimize this type of pollution.
3. Which is the govt, agency monitor pollution?

Answer:
1. CNG -Compressed Natural Gas.

2. Air pollution can be controlled by using lead free petrol & by using catalytic converters. The catalytic converters convert unburned hydro carbons into CO₂, H₂O, CO & nitric oxide are converted to CO₂ & N₂ gas.

3. CPCB (Central pollution control board).

Question 8.
Ozone balance has been disrupted due to enhancement of ozone degradation by CFC’s.

1. Enumerate the role of Cl in O₃ depletion.
2. Give a note on Montreal protocol.

Answer:
1. Ozone is found in the stratosphere It acts as shield by absorbing UV radiation from the sun. UV rays are injurious to living organisms since DNA & proteins of living organism are affected by UV rays. The refrigerators use CFC.

The CFC’s discharged into the atmosphere it reaches the stratosphere. In stratosphere UV rays act on them releasing chlorine atom. Chlorine degrade ozone and releasing molecular oxygen. As the chlorine atom are not consumed in this reaction they remain in the stratosphere & will have permanent & continuing effect on ozone level.

2. Recognizing the deleterious effects of ozone depletion an international treaty known as Montreal Protocol was signed at Montreal(canada) in 1987 & is effective from 1989. This protocol emphasizes to control the emission of ozone depleting substances.

Question 9.
Night blindness is caused by the deficiency of Vitamin. What is the cause of snow blindness.
Answer:
Due to ozone hole the UVB rays reach the earth and its high dose causes inflamation of cornea called snow blindness, cataract, etc. Such an exposure permanently damage the cornea.

Question 10.
Discuss the role of women and communities in protection and conservation of forests.
Answer:
Amrita devi bishnoi wild life protection award (in the name of lady who sacrificed her life for protecting trees), chipko movement( women belonging to garhwal showed courage by hugging trees to protect them from axe of contractors).

Question 11.
If the ESP is not fitted across the way of exhaust come out from thermal power plant. How does it affect humans.
Answer:
The particulate matter present in exhaust spread the air and causes respiratory problems like asthma, chronic bronchitis, hay fever, etc.

Question 12.
Two years ago, the lake was pure, clean and rich in variety of organisms. While now it is colourless, rich in algae and have a dirty smell. Name the pollutants and the phenomenon.
Answer:
The pollutans are phosphatic and nitrogenous in organic fertilisers. The phenomenon is called eutrophication.

Question 13.
Hundred metre surroundings of hospitals and schools are considered as silent zone. Justify it.
Answer:
It is considered as silent zone because in hospitals sound intensity increases the heart beat altering respiratory patterns of patients etc.but in schools it affects the teaching and learning process.

Question 14.
In 1990, the ozone thickness in a particular area was 190 Du while in 2001 and 2005 it was decreased to 150 Du and 135 Du respectively.

1. What is the causes of fall of Du level.
2. Which is the good ozone situated and named so?

Answer:
1. Itis due to the increased emission of chlorofluro carbons. It causes the upset of balance between formation and degradation of ozone and results in ozone depletion or thinning of ozone layer.

2. Ozone found in stratosphere filter uv rays coming into the earth.

Question 15.
CO and SO₂ are pollutants but they are different from, DDT. BHC etc. Do you agree. Give justifications of your answer.
Answer:
Yes. The former pollutants are gaseous, biodegradable and inorganic but latter are organic and non biodegradable.

Question 16.
What you meant by the auto fuel policy of Govt, of India? Name the latest reformed engine norm.
Answer:
The aim of auto fuel policy is to decrease the emission of sulphur, carbon monoxide and aromatics content in petrol and diesel fuels. Euro-IVnorms- April 1, 2010.

Question 17.
Now a days the acuumulation of plastic waste is the major problem because such wastes are non biodegradable. In some places it is used for beneficial purpose

1. Name the mixtures used by Ahmed Khan to lay down roads in Bangalore.
2. How was it minimized the accumulation of solid wastes?

Answer:

1. Polyblend and bitumen.
2. The raw material for creating Polyblend is any plastic film waste. So the accumulation of plastic wastes can be controlled.

Question 18.
Thermal Power plants are inevitable in an industrial and densely populated country like our-what harm they do to the environment? Also mention any precaution that could be taken to save our environment.
Answer:
Hot effluents of thermal power plants are generally released in the nearby water bodies. This causes rise in temperature of such water bodies which causes deoxygenation of water leading to decomposition of organic wastes and killing of aquatic animals. Thermal water pollution can be checked by employing dry or wet cooling towers.

Question 19.
Accumulation of solid waste (e-waste) is the major problem in developed countries.

1. What do you mean by e-waste?
2. Give its ill effects.

Answer:

1. It is formed of irreparable computers and other electronic goods.
2. During manual recycling of such waters in the developing countries the workers are exposed to toxic compounds present in them.

Question 20.
It is said that the use of refrigerators cause ozone depletion.

1. How is it possible?
2. Explain the process of ozone depletion.
3. Name any one treaty signed in the international level to control this phenomenon.

Answer:
1. The refrigerators emit CFC (Chloro flora carbon).

2. The CFC’s discharged into the atmosphere reaches the stratosphere. In stratosphere UV rays act on them releasing chlorine atom, chlorine Degrade ozone releasing molecular oxygen. As the chlorine atom are not consumed in this reaction they remain in the stratosphere and have permanent and continuing effect on ozone level.

3. Montreal protocol and Kyoto protocol.

Question 21.
Mention the two major environmental issues of global nature.
Answer:

1. Increasing greenhouse effect.
2. Depletion of ozone in the stratosphere.

Question 22.
Thermal power plants are inevitable in an industrial and densely populated country like ours. What harm do they do to the environment? Also mention any precaution that could be taken to save our environment.
Answer:

1. They release particulate and gaseous air pollutants, hot thermal waste kills organisms sensitive to high temperature, indigenous flora ad fauna lose.
2. Use of electrostatic precipitator.

Question 23.
1. On seeing bad state of roads in your locality, as a student, you have recommended to the Municipal corporation to use polyblend.

• What is poly blend? Point out its raw material.
• How will it be advantageous?

2. What are e-wastes? Explain the method of their disposal.
Answer:
1.

• It is a fine powder of recycled modified plastic. This mixture is mixed with bitumen used to lay roads. Raw material – Plastic film waste
• Blends of polyblend and bitumen, when used to lay roads, enhances the bitumen’s water repellent properties and helps to increase road life.

2. Irreparable computers and other electronic goods are known as e-wastes. Burried in landfills or incinerated.

Question 24.
Eutrophication is the main problem in of rivers due to the adding of more and more nitrates and phosphates.

1. How does it affect aquatic water body
2. What is algal bloom?
3. How does it related to D.O. in water bodies.

Answer:

1. It change the colour and quality of water and causes the mortality of fish
2. Presence of large amounts of nutrients in waters also causes excessive growth of planktonic(free-floating) algae, called an algal bloom
3. This results in the decrease of D.O. in water.

Question 25.
DDT content in the water of a lake, that supplies drinking water to the nearby villages, is found to 0.0Q3ppm. The kingfishers of that area are reported to have2ppm DDT.

1. Why has the concentration increased in these birds?
2. What harm will this cause to bird population?
3. Name the Phenomenon.

Answer:
1. Increase in concentration of DDT (non biodegradable) from the water bodies (0.003ppm) to the final consumers like kingfishers (2ppm) is due to increase in cone, of DDT in successive tropic levels (eg. Phytoplankton → Zooplanktons → Fishes → King Fishers) of food chain.

2. It affects ca metabolism and finally premature breaking of egg and declining bird population.

3. Biomagnification.

Question 26.
Observe the figure below.

1. Identify the greenhouse gases 1,2 and write their percentage of contribution to total global warming.
2. Write any four measures to control global warming.

Answer:
1. greenhouse gases 1,2 and write their percentage of contribution to total global warming:

• CO₂ – 60%
• CFCs 14%

2. four measures to control global warming:

• Cutting down use of fossil fuel
• Improving efficiency of energy usage
• Reducing deforestation
• Planting trees

Question 27.
Presence of large amounts of nutrients in water cause excessive growth of plankton.

1. Name this process.
2. Write the dangers caused by this process.

Answer:
1. Algal bloom.

2. Dangers caused by this process:

• Imparts a distinct colour to the water bodies
• Deterioration of the water quality
• Fish mortality
• Toxic to human beings and animals.

Question 28.
Pollutants from man’s activities like effluents from the industries and homes accelerate the aging process of lakes.

1. Name this phenomenon.
2. Write any four harmful effects of this process.

Answer:
1. Cultural or Accelerated eutrophication.

2. Any four harmful effects of this process:

• Over stimulate the growth of algae
• Cause unpleasant odor
• depletes dissolved oxygen
• Death of fish

Question 29.
CNG is better than diesel. Substantiate this statement writing any four advantage of CNG. Expand CNG.
Answer:
1.

• CNG bums most efficiently
• Cheaper than petrol or diesel
• Cannot be siphoned off by thieves
• cannot be adulterated like petrol or diesel

2. Compressed Natural Gas

Question 30.
Observe the flow chart given below.

1. Fill in the blanks 1 and 2.
2. Identify the process illustrated in the flow chart.

Answer:
1.

• Small fish (DDT 0.5 ppm)
• Large fish (DDT 2 ppm)

2. Biomagnification

Question 31.
People in the town of Areata created an integrated waste water treatment within a natural system. Explain the method.
Answer:
The cleaning of waste water is conducted in two stages. In the first stage conventional sedimentation, filtering, and chlorine treatment are given.

Through this step all materials present in water can be removed except dangerous pollutants like dissolved heavy metals.

In the second stage this heavy metal containing water is passed through a series of six connected marshes over 60 hectares of marshland.

In marshy area, plants, algae, fungi, and bacteria were seeded, they can neutralise, absorb and assimilate the pollutants as the water flows through the marshes, after this process water gets purified naturally.

Question 32.
Match the items of column A with B and C.

Answer:

Plus Two Botany Environmental Issues NCERT Questions and Answers

Question 1.
Match the items given in column A and B.

Answer:
(a) – (ii)
(b) – (i)
(c) – (iii)
(d) – (iv)

Question 2.
Write critical notes on following:

1. Eutrophication
2. Biological magnification
3. Ground-water depletion and ways for its replenishment.

Answer:
1. Natural aging of a lake by nutrient enrichment of its water.

2. Biomagnification, also known as bio amplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain.

3. The level of ground water is falling day by day due to high demand in urban areas as well as in agriculture. Due to over use of surface water, people rely on ground water for irrigation, drinking, and industrial use.

About 85% of rural water supply and more than 50% of urban and industrial supply is mined. This results in depletion of ground water.

Ground water can be replenished by-

1. Rain water harvesting
2. Reduction in consumption and waste.

Question 3.
Why ozone hole forms over Antarctica? How will enhanced ultraviolet radiation affect us?
Answer:
Decline in the thickness of ozone layer over a restricted area is called ozone hole. It was first discovered over Antarctica. Antarctica air is completely isolated from the rest of the world by natural circulation of wind called as Polar Vertex.

CFCs released in the atmosphere slowly enters the stratosphere and wind push them towards the poles. Environmental conditions prevailing in Antarctica during winter months are conductive for the formation of ozone hole.

During winter months, lack of sunlight and low temperature facilitates the formation of ice clouds, which provide the catalytic surface for the reaction of chlorine.

Effect of Ultraviolet Rays

1. UV-B radiations are very harmful.Coronea of eye absorbs these radiations and becomes inflamed. This disorder is known as ‘snow blindness’ cataract and leads to diminishing of eye sight.
2. UV-B radiations damage skin cells and cause skin cancer.

Question 4.
Discuss the role of women and communities in protection and conservation of forests.
Answer:
Women and tribal communities have played a significant role in protection and conservation of forests. Amritha devi Devi Bishnoi Wild Lide Protection Award, has instituted by government of India for individuals and rural communities for their contribution in protection of wild life.

In 1731, a woman Amritha Devi showed exemplary courage by hugging a tree to prevent its cutting. Her three daughters and hundreds of other Bishnoi followed her. They were killed by soldiers of Jodhpur.

Question 5.
What measures, as ah individual, you would like to reduce environmental pollution?
Answer:

1. I will use those articles which are either disposable or can be recycled.
2. I would help in tree plantation in my school and surroundings.
3. I will minimize the use of fossil fuels.

Plus Two Botany Environmental Issues Multiple Choice Questions and Answers

Question 1.
The maximum biological magnification of DDT through food web is seen in.
(a) Bacteria
(b) Algae
(c) Man
(d) Higher plants
Answer:
(c) Man

Question 2.
Eutrophication leads to death of fish due to
(a) Increased O₂ content
(b) Increased algae content
(c) Decreased algae content
(d) Decreased O₂ content
Answer:
(d) Decreased O₂ content

Question 3.
Match the following:-

(a) 1 – d, 2 – c,  3 – b, 4 – a
(b) 1 – a, 2 – d,  3 – c,  4 – b
(c) 1 – a, 2 – b,  3 – c,  4 – d
(d) 1 – c, 2 – d,  3 – a, 4 – b
Answer:
(c) 1 – a, 2 – b,  3 – c,  4 – d

Question 4.
Nitrogen oxides produced from the emission of automobiles and power plants are the source of fine air borne particles which lead to
(a) photochemical smog
(b) dry acid deposition
(c) industrial smog
(d) wet acid deposition
Answer:
(d) wet acid deposition

Question 5.
Drinking of mineral water with very low level of pesticides (about 0.02 ppm) For long periods may
(a) produce immunity against mosquito
(b) cause leukemia (blood cancer) in
(c) cause cancer of the intestine
(d) lead to accumulation of pesticide residues in body fat
Answer:
(d) lead to accumulation of pesticide residues in body fat

Question 6.
The soil pollutants that affect the food chain and food web by killing microorganisms and plants are
(a) nitrogen oxides
(b) pathogens chemical fertilizers
(c) agricultural waste
(d) pesticides
Answer:
(d) pesticides

Question 7.
In a coal-fired power plant, electrostatic precipitators are installed to control emission of
(a) SO
(b) NOX
(c) SPM
(d) CO
Answer:
(c) SPM

Question 8.
Green-house effect is due to the presence of
(a) ozone layer in the atmosphere
(b) moisture layer in the atmosphere
(c) CO₂ layer in the atmosphere
(d) infrared light reaching the earth
Answer:
(c) CO₂ layer in the atmosphere

Question 9.
Which one of the following pairs pf organisms are exotic species introduced in India?
(a) Ficusreligiosa, Lantana camara
(b) Lantana camara, water hyacinth
(c) water hyacinth, Prosopis cineraria
(d) Nile perch, Ficusreligiosa
Answer:
(b) Lantana camara, water hyacinth

Question 10.
A lake with an inflow of domestic sewage rich in organic waste may result in
(a) drying of the lake very soon due to algal bloom
(b) an increased production of fish due to lot of nutrients
(c) death of fish due to lake of oxygen
(d) increased population of aquatic food web organisms
Answer:
(c) death of fish due to lake of oxygen

Question 11.
A substantial fall in C02 and S02 level has been found in Delhi between 1997 and 2005 due to
(a) use of purified, unleaded petrol
(b) use of purified, unleaded diesel
(c) use of Compressed Natural Gas (CNG) in public transports
(d) use of LiquifiedPetroleam Gas (LPG) in public transports
Answer:
(c) use of Compressed Natural Gas (CNG) in public transports

Question 12.
Electrostatic precipitator is used to remove
(a) CO
(b) particulate matter
(c) lead
(d) secondary pollutant
Answer:
(b) particulate matter

Question 13.
CNG is used to control
(a) water pollution
(b) air pollution
(c) radioactive pollution
(d) thermal pollution
Answer:
(b) air pollution

Question 14.
Major pollutant present in automobile exhaust is
(a) lead
(b) CO
(c) CO₂
(d) hydrocarbon
Answer:
(b) CO

Question 15.
If there is no green house gases present in an atmosphere, the average temperature of earth surface is
(a) 100c
(b) 1000 c
(c) 00 c
(d) -150 c
Answer:
(d) -150 c

Question 16.
Deforestation activities and forest fires leads to the rise in global temperature, it is due to
(a) increase in CO level
(b) decrease in CO level
(c) increase in CO₂ level
(d) decrease in CO₂ level
Answer:
(c) increase in CO₂ level

Question 17.
A geing of lake is mainly caused by the accumulation of nutrients such as
(a) N₂ & P
(b) N₂ & P
(c) P & Ca
(d) Ca & N₂
Answer:
(b) N₂ & P

Question 18.
Appearance of hole in strato spheric ozone layer is caused by the emission of green gases, it is due to the reaction between
(a) O₃ and Cl
(b) O₃ and F
(c) O₂ and F
(d) O₂ and Cl
Answer:
(a) O₃ and Cl

Question 19.
The pollutant that seriously affect the marble monuments mainly contains the chemical have the nature is
(a) acidic
(b) basic
(c) neutral
(d) none of the above
Answer:
(a) acidic

Question 20.
Chlorinated hydrocarbons enters through one trophic level and its concentration is increased as ppm in successive trophic levels, its nature is
(a) biodegradable
(b) non biodegradable
(c) degradable on combustion
(d) not degradable on combustion
Answer:
(b) non biodegradable

Question 21.
Increase in noise level above particular dB affect the hearing abilities, that is
(a) 20 dB
(b) 60 dB
(c) 80 dB
(d) 150dB
Answer:
(d) 150dB

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Kerala Plus Two Botany Chapter Wise Questions and Answers Chapter 7 Ecosystem

Plus Two Botany Ecosystem One Mark Questions and Answers

Question 1.
The 10% law is associated with an important function of an ecosystem is
(a) Productivity
(b) Nutrient cycling
(c) Decreases the calorific value in successive trophic levels
(d) Increases the calorific value in successive trophic levels.
Answer:
(c) Decreases the calorific value in successive trophic levels

Question 2.
In the second step of trophic level, the energy storage is primarily associated with
(a) gross primary productivity
(b) net primary productivity
(c) secondary productivity
(d) none of the above
Answer:
(c) secondary productivity

Question 3.
If the energy storage at second trophic level is 4000 KJ what is the energy level of primary and secondary carnivore?
Answer:
In primary carnivore level the energy storage is 400 KJ while in second carnivore level it is 40 KJ.

Question 4.
Give an example for gaseous and sedimentary cycle
Answer:

• Gaseous cycle -Nitrogen cycle
• Sedimentary cycle – Phosphorus cycle

Question 5.
Which is the community next to lichen that occur in xerarch succession.
Answer:
Moss stage

Question 6.
In food chain transfer of energy takes place from one tropic level to the next is
(a) 5%
(b) 10%
(c) 15%
(d) 20%
Answer:
(b) 10%

Question 7.
The second trophic level in a lake is………….
(a) Phytoplankton
(b) Zooplankton
(c) Benthos
(d) Fishes
Answer:
(b) Zooplankton

Question 8.
Food chain in which microorganisms breakdown the food formed by primary producers
(a) Parasitic food chain
(b) Detritus food chain
(c) Consumerfoodcahin
(d) Predator food cahin
Answer:
(b) Detritus food chain

Question 9.
What is true of ecosystem?
(a) Primary consumers are least dependent upon producers
(b) Primary consumers out number producers
(c) Producers are more than primary consumers
(d) Secondary consumers are the largest and most powerfull
Answer:
(c) Producers are more than primary consumers

Question 10.
Which of these statements is correct?
(a) The base of the energy pyramid contains the largest trophic level.
(b) About 10% of energy available in food is actually incorporated into any trophic level.
(c) Humans are at the top of energy pyramids.
(d) All of these
Answer:
(d) All of these

Question 11.
The energy pyramid is always upright because the energy content
(a) decreases in successive trophic levels
(b) increases in successive trophic levels
(c) increases from the base to the top
(d) decreases from primary consumer to secondary consumer only
Answer:
(a) decreases in successive trophic levels

Question 12.
Which one of the following is not coming under decomposition
(a) catabolism
(b) anabolism
(c) mineralization
(d) the surface area of detritus increases
Answer:
(b) anabolism

Question 13.
Most useful step of decomposition for plants is
(a) mineralization
(b) catabolism
(c) humification
(d) fragmentation of detritus
Answer:
(a) mineralization

Question 14.
Food chains are not always linear, it is branched in some steps. Name the network of food chains.
Answer:
The network of the food chain is called food web.

Question 15.
The biotic community along with physical environment forms an interacting system called………..
Answer:
Ecosystem

Question 16.
If the energy storage at second trophic level is 4000 KJ what is the energy level of primary and secondary carnivore?
Answer:
In primary carnivore level the energy storage is 400 KJ while in second carnivore level it is 40 KJ.

Question 17.
Cite an example of an inverted ecological pyramid.
Answer:
Pyramid of number in tree ecosystem & pyramid of biomass in sea ecosystem is inverted.

Question 18.
Which among the following equation is related with net primary productivity?
(a) GPP + R = NPP
(b) NPP + GPP = R
(c) GPP – R = NPP
(d) R + R = GPP
Answer:
(c) GPP-R = NPP

Question 19.
Find out the stage given below which is not included in hydrarch succession.
(a) Forest
(b) Phytoplanktons
(c) Lichens
(d) Marsh-Meadow
Answer:
(c) Lichens

Question 20.
Which among the following decomposers.
(a) Autotrophs
(b) Saprotrophs
(c) Heterotrophs
(d) Herbivores
Answer:
(b) Saprotrophs

Question 21.
Which one of the following is a primary consumer in an aquatic ecosystem.
(a) Phytoplanktons
(b) Aquatic birds
(c) Zooplanktons
(d) Large Fishes
Answer:
(d) Zooplanktons

Plus Two Botany Ecosystem Two Mark Questions and Answers

Question 1.
GPP-R= NPP is an equation indicating productivity. Illustrate the terms denoted in the equation.
Answer:
GPP is the gross primary productivity which is the rate of production of organic matter during photosynthesis. R- is the respiration loses which is the amount of GPP utilized by plants in respiration. NPP is the available biomass for the consumption to hetrotrophs. (Herbivores and Decomposers).

Question 2.
Decomposition is the breakdown of complex organic matter into inorganic substances like C0₂, Water, etc.

1. Identify the gas which is most essential for decomposition.
2. Find out any two conditions which inhibit decomposition.

Answer:

1. Oxygen
2. Low temperature Anaerobiosis

Question 3.
Vast area of vegetation is destroyed mostly by fires and it results in clearing of lush vegetation. How long it takes to re-form climax community. Name the process is related in the above case.
Answer:
Time taken is about 50-100 years in case of a grassland and about 100-200 years for a forest. Secondary succession.

Question 4.
Healthy ecosystems are the base for a wide range of goods and services. Find out any four ecosystem services provided by a healthy forest ecosystem.
Answer:

1. Purify air and water
2. Mitigate drought and floods
3. Cycling of nutrients
4. Generate fertile soils

Question 5.
Differentiate between Standing state and Standing Crop.
Answer:
1. Standing crop
The amount of living material present in each trophic level.

2. Standing state
The amount of nutrients like carbon, nitrogen, phosphorus, calcium, etc present in the soil at a given time.

Question 6.
Distinguish between Grazing food chain and Detritus food chain.
Answer:
1. Grazing food chain
It starts with producers. In aquatic ecosystem major fraction of energy flow take place through GFCthan DFC.

2. Detritus food chain
It starts with detritus. In terrestrial ecosystem major fraction of energy flow take place through DFC than GFC.

Question 7.
Xerarch succession is mainly occurs in desert conditions

1. Name the pioneefspecies on a bare rock.
2. How do pioneer species help in establishing the next type of vegetation.

Answer:

1. Lichens
2. They secrete carbonic acid and dissolve rocks. This process forms soil to help growth of mosses.

Question 8.
Energy flow is always unidirectional, never return back. Do you agree. Give the justification of your answer.
Answer:
Yes. The flow of energy is based on thermodynamic laws.lt starts from producers and flows through successive trophiclevels, The efficiency of energy transfer from one trophic level to the next is 10%.

Question 9.
A Volcano erupted in Hawaii, and lava covered land that had been framed for centuries. Eventually, new lichens, and then plants, grew on the lava.

1. Is this an example of primary or secondary successions?
2. Give the reason also.

Answer:

1. This is an example of primary succession
2. Because it begins from a state of little or no life.

Question 10.
Decomposition is the process in which complex dead matters are broken down into simpler inorganic substances,

1. Name the step of decomposition in which biological activity not found?
2. Chemical composition of detritus influence decomposition why?

Answer:

1. Humification
2. If the detritus rich in Lignin and c.hitinthe rate of decomposition is very slow but it is rich in nitrogenous compounds and Sugars the rate of decomposition is very high.

Question 11.
Decaying Biomass is formed through the process of decomposition, from which different types of mineral ions are released based on the mineralisers act on it.

1. Name the microorganisms that helps to release phosphate and nitrate into the soil
2. Give an example for nutrient cycling that helps in the photosynthesis of land plants.

Answer:

1. Phosphate solubilizing bacteria and nitrifying bacteria
2. Carbon cycle

Question 12.
In Barren lands succession continuous and forms climax vegetation after many years

1. Name the Pioneer community formed.
2. Which is the community comes next to Pioneer community?

Answer:

1. lichen
2. bryophytes

Question 13.
Productivity is one of the key function of an ecosystem, it varies in different ecosystems.

1. Distinguish between primary productivity and secondary productivity.
2. Some Terrestrial ecosystem shows abundant and least productivity. Name it.

Answer:

1. Primary productivity is associated with producers while secondary productivity is associated with consumers.
2. Abundant productivity is found in tropical rainforest Least productivity is found in desert.

Question 14.
How can you differentiate primary productivity from secondary productivity?
Answer:

1. Primary productivity-productivity at producer level
2. Secondary productivity – productivity at consumer level

Question 15.
Mention the functions of ecosystem.
Answer:

• Productivity
• Decomposition
• Energy flow
• Nutrient cycling

Question 16.
Connect the terms in the column A with suitable definition given below and fill up column B.

(a) Rate of biomass production.
(b) Rate of storage of organic matter by producers in excess of their metabolic consumption.
(c) Rate of production of organic matter by plants during photosynthesis.
(d) Rate of formation of new organic matter by consumers.
Answer:

1. b
2. c
3. a
4. d

Question 17.
Measurement of biomass in terms of dry weight is more accurate than fresh weight. Why?
Answer:
Fresh Weight contains weight of water present inside the cells as cell sap. Whereas dry weight is the actual weight of the materials making up the body of the organism.

Question 18.
Leaching, detritus, catabolism, humification, fragmentation, mineralization, detritivores, humus. Given above are the terms involved in the process of decomposition. Arrange them in the correct sequence.
Answer:
Detritus? detritivore? fragmentation? leaching? catabolism? humification? humus? Mineralization.

Question 19.
The given table shows the dry weight of different trophic levels of forest ecosystem.

1. From the given data construct a pyramid of biomas.

2. if you select Lake ecosystem to construct pyramid of biomas, it contain producers (Phytoplanktons), Herbivores (Short lived fishes) and Carnivores (Long lived fishes) with dry weight 2mgm-3, 7mgm-3 and 9mgm-3 respectively. From the data construct a pyramid of biomas.
Answer:
1.

2.

Question 20.
Energy is an important key functional component of ecosystem and pyramid of energy is always upright.

1. Do you agree with this statement.
2. Give reason.

Answer:

1. Yes
2. Energy transfer in a pyramid follows the ll nd law of thermodynamics . It also obeys the 10 % law (only 10 % of energy is transferred to each tropic level from the lower tropic level).

Question 21.
In nature there is no independent food chain.

1. Do you agree with the statement? Justify?
2. Decomposers have important role in nutrient cycling. Substantiate.

Answer:
1. Yes. The members of one food chain depends the members of other food chains and forms interconnections.

2. Detritus or dead remains are broken down by detritivores catabolism results in breaking down of complex molecules by decomposers. This results in the formation of mineral nutrients into the soil, thereby recycling of nutrients are achieved.

Question 22.
While visiting a forest, Ranjan’s grandfather told that long back it was a pond.

1. Name the phenomenon takes place here.
2. Write down the different stages of that process.

Answer:

1. Hydrach
2. Phytoplankton stage – Submerged plant-stage – Submerged free floaloting plant stage – Reed swamp stage – Marsh meadow stage — Scrub stage – Forest stage.

Question 23.
Human activities have a significant role in carbon cycle.

1. Do you agree with the statement?
2. Mention the environmental hazard caused by excess release of CO₂?

Answer:
1. Yes.

2. Deforestation activities and massive burning of fossil fuels increase the amount of CO₂ in the atmosphere that causes reradiation of reflected solar radiations. This leads to heating of the troposphere called green house effect.

Question 24.
Ecological succession and species evolution would have been a parallel process. Justify.
Answer:
As succession gives to the replacement of one community by another and establishment of dominant species it can be considering as parallel steps to evolution.

Question 25.
Sedimentary cycle that occure in lithosphere

1. Give an example for sedimentary cycle.
2. Give a flow chart representing the above cycle.

Answer:
1. Phosphorous cycle.

2. The cycle consists of following steps.

Question 26.
The atmosphere contains only about 1% of total global carbon. But carbon cycle is an gaseous cycle since the reservoir is atmospheric CO₂. Justify.
Answer:
71% of carbon is found dissolved in oceans which regulates the amount of CO₂ in the atmosphere. Fossil fuels also represents a reservoir of carbon. Carbon cycle is considered as gaseous cycle since the cycling occurs through atmosphere, ocean and through living and dead organisms.

The CO₂ is released to the atmosphere by burning of fuels, processing of waste materials in land and ocean and hence it act as a reservoir of CO₂ in an ecosystem.

Question 27.
Why is the length of a food chain in an ecosystem generally limited to 3-4 trophic levels?
Answer:
Energy requirement for maintenance of body rises successively with higher level. As 90% energy is lost when it moves from one trophic level to the next, the residual energy decreases drastically within 2-3 trophic levels, as a result an ecosystem can support only limited number of trophic levels.

Question 28.
Name the type of food chain responsible for the flow of larger fraction of energy in aquatic and a terrestrial ecosystem respectively. Mention one difference between two food chains.
Answer:
In an aquatic ecosystem GFC is the major conduits for energy flow where as in terrestrial ecosystem a much larger fraction of energy flow through the detritus food chain than through the GFC. Detritus food chain may be connected with the grazing food chain at some levels.

Difference between two food chains:
Detritus food chain always start with dead organic matter where as GFC starts with plants.

Question 29.
A volcano erupted in Hawaii, and lava covered land that had been framed for centuries. Eventually new lichens and then plants grew on the lava.

1. Is this an example of primary or secondary successions?
2. Give the reason.

Answer:

1. Yes
2. This is an example of primary succession because this begins from a state of little or no life.

Question 30.
Distinguish between grazing and detritus food chain. Name the type of food chain helps in the flow of major fraction of energy through aquatic ecosystem.
Answer:

• The food chain start with producers are called grazing food chain.
• It start with dead organic matters is called detritus food chain.
• In an aquatic ecosystem, majorfraction of energy flow occurs through GFC.

Question 31.
In lake ecosystem .biomass of trophic levels are different

1. Do you agree the pyramid of biomass is inverted.
2. Give reason.

Answer:

1. Yes
2. In lake ecosystem producers are phyto-planktons. The short lived and long lived fishes are arranged above the lelvel of producers.Here biomass is increased from base to the top of pyramid.

Question 32.
How much PAR is used by producers for gross primary productivity?
Answer:
Of the incident solar radiation less than 50 percent of it is photosynthetically active radiation(PAR. Plants capture only 2-10 per cent of the PAR for gross primary productivity.

Question 33.
Differentiate between a detrivore and a decomposer giving an example of each.
Answer:
Detrivores are the primary consumers of a detritus food chain which feed upon the detritus and include protozoan, bacteria, and fungi, while decompers form the last trophic level of both detritus and grazing food chains and break down complex organic compounds of dead plants and animals and include bacteria and fungi.

Question 34.
Why is the length of a food chain in an ecosystem generally limited to 3-4 trophic levels?
Answer:
Energy requirement for maintenance of body rises successively with higher level. As 90% energy is lost when it moves from one trophic level to the next, the residual energy decreases drastically within 2 – 3 trophic levels. As a result an ecosystem can support only a limited number of trophic levels.

Question 35.
Due to uncontrolled excessive hunting the population of tigers in a forest becomes zero. What are the long term effects of this situation on the population of deer in that forest.
Answer:
The reduction in predator population may result in the increase of prey population (deer), since they are not preyed upon. Increase in the number of deer will lead to overgrazing, hence, shortage of herbs and eventually reduction in the number of deer.

Question 36.
A Volcano erupted in Hawaii, and lava covered land that had been framed for centuries. Eventually, new lichens, and then plants, grew on the lava. Is this an example of primary or secondary successions? Give the reason also.
Answer:
This is an example of primary succession Because this begins from a .state of little or no life.

Question 37.
How can you differentiate primary productivity from secondary productivity?
Answer:

1. Primary productivity-productivity at producer level
2. Secondary productivity – productivity at consumer level

Question 38.
Observe the flow chart on functional components of ecosystem given below.

1. Identify the components given as A and B
2. What is stratification?

Answer:
1. components given as A and B:
A = Energy flow
B = Nutrient cycling

OR

A = Nutrient cycling
B = energy flow

2. Vertical distribution of different species occupying different levels.

Question 39.
Observe the food chain given below. Grass? Goat? Man

1. Identify the type of food chain,
2. How does it differ from detritus food chain?

Answer:

1. Grazing Food Chain
2. Grazing food chain starts with producers while detritus food chain starts with dead organic matter.

Question 40.
Given below is the flow chart of ecological succession occur in water bodies.

1. Identify the stages A, B, C, D, E and F
2. What is this succession called?

Answer:
1. The stages A, B, C, D, E, and F:

• A = Submerged plant stage
• B = Submerged free floating plant stage
• C = Reed-swamp stage
• D = Marsh-meadow stage
• E = Scrub stage
• F = Forest stage

2. Hydrarch succession

Question 41.
Given below is a simplified model of a nutrient cycling in a terrestrial ecosystem.

1. Identify the cycle?
2. How does it differ from a gaseous cycle?

Answer:

1. Phosphorus cycle
2. This cycle starts from earth’s crust(lithosphere) but gaseous cycle exists in atmosphere.

Question 42.
Decomposition of detritus is a complex process. Decomposition has various steps. Identify the steps given below and fill the blanks.

Answer:

1. Fragmentation
2. Leaching
3. Catabolism
4. Humification

Question 43.
Decomposition is the breakdown of complex organic matter into inorganic substances like CO₂, Water, etc.

1. Identify the gas which is most essential for decomposition.
2. Find out any two conditions which inhibit decomposition.

Answer:

1. Oxygen
2. Low temperature, Anaerobiosis.

Question 44.
In most ecosystems, all the pyramids of number, biomass, and energy are upright. Suggest on occasion each where the pyramid of number and pyramid of biomass are inverted.
Answer:
When a big tree is considered as an ecosystem- pyramid of number is inverted. Pyramid of biomass in sea is also inverted.

Question 45.
Ecological pyramids express the food or energy relationship between organisms, Write any three limitations of ecological pyramids.
Answer:

1. In some cases same species may belong to two or more trophic levels
2. It does not represent food web
3. Saprophytes are not given any place

Question 46.
Analyze the table given below and fill in the blanks suitably.

Answer:

1. Standing crop
2. The amount of nutrients presents in the soil or eosystem at any given time

Question 47.
Match the items of column A with column B
VAnswer:
(a) – (v)
(b) – (iii)
(c) – (ii)
(d) – (i)

Question 48.
Human activities have significantly influenced the carbon cycle by increasing the amount of C02- production. Justify this statement with minimum two points.
Answer:

1. It lead to rapid deforestation.
2. Massive burning of fossil fuel for energy and transport.

Question 49.
Given below is simplified mode of a biogeochemical cycle.
Fill up the blanks a), b), c) and d)

Answer:

1. Rock minerals
2. Producers
3. Consumers
4. Detritus

Question 50.
Construct a pyramid of biomass using the data given below.
PC 37Kgm^-2 TC 1.5Kgm^-2
PP 809Kgm^-2 SC 11Kgm^-2
Answer:

Question 51.
Carbon cycle and phosphorus cycle are two common biogeochemical cycles. Write any three differences between these two cylces.
Answer:

Plus Two Botany Ecosystem Three Mark Questions and Answers

Question 1.
Primary succession is a long term process, while secondary succession is a short term process.

1. Do you agree?
2. Give reasons.
3. Name the pioneer species in hydrarch succession

Answer:
1. Yes.

2. In primary succession development of forest climax on a barren land may take about 1,000 years but in secondary succession it takes 50 – 100 years in case of a grassland and about 100 – 200 years for a forest.

3. Phtoplanktons.

Question 2.
Succession on different habitat are different in nature

1. Name the pioneer species on a bare rock.
2. How do they help in establishing the next type of vegetation?
3. Mention the type of climax community that will ultimately get established.

Answer:

1. Lichens are the pioneer species:
2. They absorb water due to their spongy structure and secrete carbonic acid which loosens rock particles and help in weathering of rocks and soil formation; thus, they pave way to some small plants like bryophytes.
3. The climax community will be a forest.

Question 3.
Most of the existing communities are evolved through a series of intermediate stage.

1. Name three plant communites that appear during ecological succession.
2. Elucidate the dynamic changes that happens in a water body.

Answer:
1. three plant communites that appear during ecological succession:

• Pioneer community
• Serai community (transitional community)
• Climax community

2. Phytoplankton stage? Submerged plant stage? Submerged free floating plant stage? Reed swamp stage? Marsh meadow stage? Scrub stage? Forest stage.

Question 4.
If decomposition not occur in nature huge amount of detritus of plants and animals may fill our ecosystems, it is seriously harm to living organisms of our environment

1. Define decomposition
2. Give the steps
3. Decomposers are known as scavengers of earth”. Justify.

Answer:
1. Breaking down of complex organic matter into simple inorganic substance like C02, H20 and Nutrients is called decomposition.

2. Decomposition steps are

• Fragmentation – It is the breaking down of detritus into smaller particle by the detrivores like earthworm.
• Leaching – Precipitation of water soluble or inorganic nutrient into soil horizon.
• Catabolism – It is the degradation of detritus into simple inorganic substances by the action of micro organism.
• Humification – It is the accumulation of dark coloured amorphous substance called humus. Humus serve as the reservoir of nutrients.
• Mineralization – The degradation of humus & release of nutrients from it by microbes is called mineralization.

3. Decomposers split the complex detritus into simple inorganic compounds while doing so they also bring about nutrient cycling. The degradation of detritus into simple organic substances by micro organism involves catabolic process. Without micro organism the earth would have been filled with dead organisms.

Question 5.
In an ecosystem there is unidirectional flow of energy and cyclic flow of matter.

1. Do you agree with the statement.
2. Give reason?
3. Mention the significance of standing crop and standing state in this contest.

Answer:
1. Yes.

2. Energy in an ecosystem flows unidirectionally from producers to different consumers through different tropic level. The constant supply of matter (nutrients like C, N„, P, Ca, etc.) are never lost from the ecosystem. Their constant supply is maintained by nutrient cycling.

3. The mass of living material in a tropic level at a particular time is a standing crop. The amount of nutrients present in a soil at a given time is called standing state.

Question 6.
Robert Constanza and his colleagues put price tags on nature’s life-support services. Price tag of US $ 33 trillion a year

1. What is meant by, ecosystem services? Give example.
2. Which is the most price lagged ecosystem service in nature?

Answer:
1. The product ecosystem process

• Generate fertile soil
• Pollinate crops

2. Soil creation is the most prize tagged ecosystem service.

Question 7.
Decomposition is largely an oxygen requiring process. Rate of decomposition depend upon many factors.

1. What are the factors influence the rate of decomposition
2. Explain it.

Answer:
1. The factors influencing the rate of decomposition are:

• Chemical nature of detritus
• Climatic condition (temperature and soil moistures)

2. Detritus which is rich in N₂ and water soluble substances like sugar decompose quickly than detritus containing lignin and chitin.

Warm and moist environment favour decomposition whereas low temperature and anaerobic condition inhibit decomposition.

Question 8.
The number of individuals in grass land ecosystem is given below.
Grass – 5842,000
Grasshopper – 7,08,000
Frogs – 3,54,000
Snakes – 3

1. Draw a pyramid representing the relationship of the given organisms in terms of number.
2. Give justification for the shape of pyramid.

Answer:
1.

2. The pyramid is an upright one the largest number being producers (grasses) forms the base of the pyramid. The Herbivores or primary consumer at the next level (grass hopper) are second to producers in number.

The third layer is occupied by secondary consumers (Frogs) which are smaller in number compared to the primary consumer. The tertiary consumer (snakes) are the least in number and occupies the top most level. Thus an upright pyramid is obtained.

Question 9.
Food chain ensures unidirectional flow of energy from producerto different levels of consumers. Construct a food chain? Is the flow of energy obey the law of thermodynamics?
Answer:

Yes, the first law of thermodynamics states that energy can neither be created nor destroyed; it can be converted from one form to another. In an ecosystem the plants capture 2-10% of PAR (Photosynthetically active radiation) from the sun.

The solar energy captured by plants flows through different organisms of an ecosystem in the form of food energy. This unidirectional flow of solar energy in accordance with 10% law.

Question 10.
Most of the existing communities are evolved through a series of intermediate stage.

1. Substantiate the above statement with the process involved in the above phenomenon.
2. Elucidate the dynamic changes that happens in a water body.

Answer:
1. Plant succession:
The gradual & predictable change in species composition or communities of a given area is called ecological successions. It occurs due to the change of communities in response to environmental changes. Important features of ecological successions are

• Invasion of a bare area by pioneer community
• sequence of communities that successfully change or modify the particular area called seres
• change in the diversity of species and organism in the successive serai communities
• formation of climax community.

2. Phytoplankton stage → Submerged plant stage → Submerged free-floating plant stage → Reed swamp stage → Marsh meadow stage → Scrub stage → Forest stage.

Question 11.
In an ecosystem flow of energy through successive trophic levels decreases, this is very common in aquatic and terrestrial habitat.

1. Write down the first and second thermodynamic laws supports energy flow
2. What do you meant by 10% law

Answer:
1. In first law of thermodynamics energy can be transferred from one state to other while in second law of thermodynamics energy losses in the form of heat.

Question 12.
The average price tag of US is 22 trillion US dollars a year.

1. What does this data indicate?
2. How is it related to GNP?'(Gross National Production)
3. Which is the most price lagged ecosystem service in nature?

Answer:
1. Ecosystem are the base of wide range of economic, environmental and aesthetic goods and services. The products of ecosystem process are named as ecosystem services.

These services are usually taken for granted because they are free. Researches have tried to put prize tags on nature’s life support services in order to understand the values of services provided by nature.

2. Gross national production is the value of human resources and services of a particular country. It is only half the value of ecosystem services.

3. Soil creation is the most prize tagged ecosystem service.

Question 13.
Primary productivity varies in different types of ecosystems.

1. What is meant by primary productivity.
2. Give reason with suitable examples.

Answer:
1. Primary productivity is the amount of biomass or organic matter produced during photosynthesis. The gross primary productivity is the rate of production of organic matter during photosynthesis.

A considerable amount of GPP is utilized by plant in respiration. The gross primary productivity – Respiration losses is the net primary productivity.

2. In some ecosystems producers number and nutrient content are not stable.

Question 14.
In most ecosystems, all the pyramids are upright. But there are exceptions to this generalisation.

1. Give any of the cases where pyramid of number and biomass becomes inverted.
2. What is detritus food chain?

Answer:
1. The pyramid of number in a tree ecosystem is inverted. The primary producer tree is a single unit. The consumers like insects, small birds & large birds are the primary consumers secondary consumers &territory consumers respectively.

Thus the no. of consumer in tree ecosystem is more than that of the producer. The pyramid of biomass in sea is inverted because the biomass of fishes (Consumers) exceeds that of phytoplankton (producer).

2. Food chain starts with detritus called as detritus food chain.

Plus Two Botany Ecosystem NCERT Questions and Answers

Question 1.

1. Plants are called as_____because they fix carbon dioxide.
2. In an ecosystem dominated by trees, the pyramid (of numbers) is_____type.
3. In aquatic eco systems, the limiting factor for the productivity is_______
4. Common ditritivores in our eco system are______
5. The major reservoir of carbon on earth is______

Answer:

1. Producers
2. Upright
3. Availability of sunlight.
4. Earthworm
5. Ocean

Question 2.
Which one of the following has the largest population in a food chain______
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers
Answer:
The decomposers can have the maximum population but they are excluded from food chain, hence the correct answer is – (a) Producers

Question 3.
The second trophic level in a lake is______
(a) Phytoplankton
(b) Zooplankton
(c) Benthos
(d) Fishes
Answer:
(b) Zooplankton

Question 4.
What is the percentage of photosyntheticaliy active radiation (PAR) , if incident solar radiation is considered 100%?
(a) 100%
(b) 50%
(c) 1-5%
(d) 2-10%
Answer:
(b) 50%

Question 5.
Give an account for flow of energy in an ecosystem.
Answer:
1. Flow of energy in an ecosystem is unidirectional from producers to consumers.

2. The flow of energy obeys the laws of the thermodynamics 2-10% of radiant energy (50% of which reaches the earth) is photosyntheticaliy active radiation. It travels through different tropic levels from producers in the form of food energy.

The producers convert radiant energy into chemical energy which is stored as biomass. When energy flows from one tropic level to another only 10% of the total energy is transferred, as certain amount of energy is utilized by the organism belonging to a particulartropic level.

Plus Two Botany Ecosystem Multiple Choice Questions and Answers

Question 1.
Which one of the following is not used for construction of ecological pyramids?
(a) Dry weight
(b) Number of individuals
(c) Rate of energy flow
(d) Fresh weight
Answer:
(d) Fresh weight

Question 2.
Which of the following is expected to have the highest value (gm/m2/yr) in a Grassland ecosystem?
(a) Secondary production
(b) Tertiary production
(c) Gross production
(d) Net production
Answer:
(c) Gross production

Question 3.
Which of the following ecosystem types has the highest annual net primary Productivity?
(a) Tropical rain forest
(b) Tropical deciduous forest
(c) Temperate evergreen forest
(d) Temperate deciduous forest
Answer:
(a) Tropical rain forest

Question 4.
An ecosystem, which can be easily damaged but can recover after some time if damaging effect stops, will be having
(a) low stability and high resilience
(b) high stability and low resilience
(c) low stability and low resilience
(d) high stability and high resilience
Answer:
(a) low stability and high resilience

Question 5.
The minimum number of components required for an ecosystem to survive
(a) Producer and primary consumer
(b) Producer and decomposer
(c) primary Consumer and decomposer
(d) primary and secondary Consumer
Answer:
(b) Producer and decomposer

Question 6.
In plant succession, when climax is reached, the net productivity
(a) continues to increase
(b) becomes halved
(c) becomes stable
(d) becomes zero
Answer:
(c) becomes stable

Question 7.
Detrivores are
(a) detritus eating vertebrates
(b) detritus eating fungus
(c) detritus decomposing bacteria
(d) detritus eating invertebrates
Answer:
(d) detritus eating invertebrates

Question 8.
How fig tree is benefited to its pollinator wasp?
(a) Pollens are edible
(b) Wasp lays eggs in fig fruits
(c) Floral petal resembles female to pseudo coupulate
(d) All of these
Answer:
(b) Wasp lays eggs in fig fruits

Question 9.
Which of the following contribute to the carbon cycle?
(a) Photosynthesis
(b) Respiration
(c) Fossil fuel combustion
(d) All of these
Answer:
(d) All of these

Question 10.
Weathering of rocks makes phosphorous available to
(a) Decomposers
(b) Consumers
(c) Producers
(d) All of the above
Answer:
(c) Producers

Question 11.
The 10% law associated with an important function of an ecosystem is
(a) productivity
(b) nutrient cycling
(c) decreases the calorific value in successive trophic levels
(d) increases the calorific value in successive trophic levels.
Answer:
(c) decreases the calorific value in successive trophic levels

Question 12.
In the reductive process, the conversion of nitrogen into ammonia occurs by
(a) nitrosomonas
(b) rhizobium
(c) nitrococcus
(d) pseudomonas
Answer:
(b) rhizobium

Question 13.
The primary productivity is least in
(a) coral reef
(b) grassland
(c) coniferous forest
(d) desert
Answer:
(d) desert

Question 14.
Choose the correct arrangement of plant communities
(a) marsh meadow stage, free floating stage, scrub stage and forest stage
(b) free floating stage, marsh meadow stage, scrub stage and forest stage
(c) marsh meadow stage, free floating stage, scrub stage and forest stage
(d) marsh meadow stage, woodland stage, scrub stage and forest stage
Answer:
(b) free floating stage, marsh meadow stage, scrub stage and forest stage

Question 15.
In the second step of trophic level, the energy storage is primarily associated with
(a) gross primary productivity
(b) net primary productivity
(c) secondary productivity
(d) none of the above
Answer:
(c) secondary productivity

Question 16.
Detritus is the
(a) dead remains of plants only
(b) dead remains of plants and animals
(c) excretory products of animals
(d) both b and c
Answer:
(d) both b and c

Question 17.
The plants efficiency of N₂ absorption is promoted when the nitrogen source available in the form of
(a) NO^3-
(b) NO^2-
(c) NH⁴⁺
(d) none of the above
Answer:
(a) NO^3-

Question 18.
Which one of the following process is associated with oxidation
(a) ammonification
(b) nitrification
(c) denitrification
(d) none of the above
Answer:
(b) nitrification

Question 19.
PAR belongs to the wavelength of
(a) 300-400 A0
(b) 400-700A0
(c) 600-800A0
(d) 700-1000A0
Answer:
(b) 400-700A0

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