Plus Two Botany Chapter Wise Previous Questions Chapter 8 Environmental Issues

Kerala State Board New Syllabus Plus Two Botany Chapter Wise Previous Questions and Answers Chapter 8 Environmental Issues.

Kerala Plus Two Botany Chapter Wise Previous Questions Chapter 8 Environmental Issues

Question 1.
Destruction of forest leads to the increase of CO, in atmosphere. Recently Govt, of India instituted an award for individuals or communities from rural areas that shown extraordinary courage and dedication in protecting wildlife. (MARCH-2010)
a) Identify the award.
b) Comment on deforestation and reforestation.
Answer:
a) Amrita Devi Bishnoi award
b) Deforestation cutting down of forest trees Reforestation replanting trees which are already destroyed.

Question 2.
Industrial effluents and domestic sewage seriously affect fresh water bodies. For protecting aquatic life Govt, of India recently declared an animal as National aquatic animal. (MARCH-2010)
a) Identify the animal.
b) Distinguish biomagnification from eutrophication.
Answer:
a) Dolphin
b) Bio magnification is the increase in the amount of non biodegradable substance in successive trophic level in a food chain.
Eg: DDT Eutrophication is the overgrowth of aquatic plants as a result of accumulation of nutrients in water body.

Question 3.
In 1990s, Delhi ranked 4th among the most polluted cities of the world. But now air quality of Delhi has significantly improved mainly by switching vehicles from diesel to CNG. (MAY-2010)
a) Expand CNG.
b) CNG is betterthan diesel. Comment.
Answer:
a) Compressed Natural Gas
b) CNG is compressed natural gas. It burns more efficiently than Petrol and diesel, thus brings down the amount of pollutants from automobiles (unbumt hydrocarbons).

Question 4.
Greenhouse effect is a naturally occuring phenomenon that is responsible for heating of earth’s surface and atmosphere. (MAY-2010)
a) Explain greenhouse effect.
b) What will happen if there is absolutely no greenhouse effect over earth’s surface ?
Answer:
a) The greenhouse gases such as CO₂, N₂0, Methane present in the atmosphere will reradiate the reflected infrared radiations. Thus raising the temperature of earth.
b) It will affect the climate of earth as the greenhouse effect causes melting of snow in the polar regions. This will in turn determine the level of water in the sea.

Question 5.
Arrange the following words into suitable categories in the given table. (MARCH-2011)
Algal bloom, Catalytic converter, Eichhornia, Electrostatic precipitator

Answer:

Question 6.
Geetha resides in a city nearby a lake. Water from this lake was used for various domestic purposes earlier. Now-a-days. this water has become turbid and is with an unpleasant odour. (MARCH-2011)
a) What can be the reason for this ?
b) Name the scientific term that explains this effect.
Answer:
a) Nutrient enrichment
b) Eutrophication or Aging of lake

Question 7.
As Head of the Vehicle Department, issue a notice to vehicle owners to observe any two measures to reduce vehicular air pollution and record the merits and demerits of CNG. (MAY-2011)
Answer:
Use of catalytic converter.
Use of lead-free petrol or diesel.
Merits of CNG
1) It burns most efficiently,
2) It is cheaper than petrol or diesel, cannot be siphoned off by thieves and adulterated like petrol or diesel.
Demerits of CNG
It is difficult of laying down pipelines to deliver CNG through distribution points/pumps and ensuring uninterrupted supply.

Question 8.
increase in green house gases. Name two green house gases. (MAY-2011)
Answer:
Green house gases – CO₂ and CFC

Question 9.
The increased use of chemicals like CFCs (Chloro fluro carbons) cause adverse ecological impacts. Why CFCs are considered harmful to the environment? Mil It causes the depletion of ozone layer. (MARCH-2012)
Answer:
CFC is considered as green house gas.lt causes global warming.
The incoming UV rays cuases many diseases like skin cancer,snow blindness etc.

Question 10.
Meena an environmental activist, noticed a gradual decline in the’population of birds in the open agricultural fields near her place. She has heard of the excessive use of pesticides like DDT around that area. (MARCH-2012)
a) What might have led to the decline of bird population in that area?
b) Name the process that has caused this phenomenon.
Answer:
a) It disturbs calcium metabolism in birds due to accumulation of DDT and causes the thinning of egg shell. lt affects the premature breaking of egg.
b) Biomagnification.

Question 11.
Ammu read in the newspaper that, BOD of a water body in a nearby village was high and there is algal bloom. (MAY-2012)
a) What is BOD ?
b) What is algal bloom ?
c) Can you give possible reason for these phenomenon?
Answer:
a) Biological oxygen demand
b) Inceased algal population
c) It is due to the accumulation of inorganic nutrients like phosphate and nitrate in water body

Question 12.
Enviornmentalists usually says: There are many causes for biodiversity losses’. Illustrate four major causes of biodiversity loss. (MARCH-2013)
Answer:
i) Habitat loss and fragmentation
ii) Over-exploitation
iii) Alien species invasions
iv) Co-extinctions

Question 13.
In a study conducted, the concentration of DDT was found to increase in the successive trophic levels, The results of the study is shown below: (MAY-2013)

Answer:
Biomagnification
High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of eggshell and their premature breaking, eventually causing decline in bird populations.

Question 14.
An article in the newspaper reports that ‘Refirigerants like Chlorofluorocarbons (CFCs) pose threat to the environment’. How CFCs are harmful to the environment? (MARCH-2014)
Answer:
CFC (CCI2F2) splits in the presence of UV and release active chlorine. This active chlorine breaks ozone molecule into O₂ and (O) .It causes the thinning of stratospheric good ozone and harmful UV rays reaches earth surface.

Question 15.
Now a days many farmers are interested in organic farming. What is meant by organic farming? Can you suggest any two advantages of organic farming?  (MARCH-2014)
Answer:
It is the cyclical, sustainable and zero-waste procedure.
Advantageous
1) No need of chemical fertilizers.
2) No need of insecticides and pesticides.
3) Never kills microorganisms in the soil.

Question 16.
An aquatic ecosystem having luxurious growth of cyanobacteria (Algal bloom) leads to eutrophication.  (MARCH-2015)
a) What kind of pollutants cause algal bloom to colonize the aquatic ecosystem?
b) What are the consequences of eutrophication?
Answer:
a) Waste water contains contains large quatities of nutrients.
b) It causes ageing of lake and damage to indigenous flora and fauna.

Question 17.
During the past century, the temperature of the earth has increased by 0.6°C, most of it during the last few decades. Rise in temperature causes deleterious changes in the environment, thus leading to increased melting of polar ice caps as well as other places like Himalayan snow caps. Suggest any two control measures that will reduce global warming?  (MARCH-2015)
Answer:
1) Cutting down use of fossil fuel
2) limproving efficiency of energy usage
3) Reducing deforestation
4) Planting trees and slowing down the growth of human population.

Question 18.
Observe the diagram and answer the following:  (MAY-2015)

a) Suggest the reasons for the presence of DDT in the water.
b) Fish eating birds of this area have higher DDT concentration in their body. Justify.
c) What will be the impact of DDT in the birds?
OR
United Nations Framework convention on climate change, an international treaty signed by 194 countries to cooperatively discuss global climate change and its impact.
As a science student,
a) What is global warming?
b) Explain the reasons and give suggestions to control global warming?
Answer:
a) Use of pesticide in agricultural field
b) DDT is accumulated in successive trophic level and finally its concentration is very high fish eating birds.
c) DDT affect calcium metabolism, that causes thinning of eggshell and premature breaking of egg. Hence the bird population is decreased.
OR
a) Increasing the temperature of earth surface due to green house effect is called global warming
b) The incoming radiations of sunlight reaches the earth’s surface re-emits heat in the form of infrared radiation but part of this does not escape into space as atmospheric gases (e.g., carbon dioxide, methane,CFCand nitrogen oxides) absorb a major fraction of it. This cycle is repeated many a times and temperature of earth increases it leads to global warming.
It is reduced by

1. cutting down use of fossil fuel.
2.  improving efficiency of energy usage.
3. reducing deforestation.
4. planting trees and slowing down the growth of human population.

Question 19.
Increase in the concentration of toxicants at successive trophic level is called _____.  (MARCH-2016)
a) BOD
b) Biomagnification
c) Eutrophication
d) Algal Bloom
Answer:
b) Biomagnification

Question 20.
The major pollution in the environment is caused by automobiles. Expand the term CNG. Mention any two of its merits. (MARCH-2016)
Answer:
CNG – compressed natural gas It burn efficiently
It is cheaper than diesel and petrol

Question 21.
Temperature is generally increasing making the earth a hot plate. Mention any two measures to control global warming. (MARCH-2016)
Answer:
Cutting down the use of fossil fuel
Improving the efficiency of energy usage

Question 22.
Quantity of pollutants increase in successive trophic levels. Observe the flowchart regarding biomagnifications of DDT in an aquatic food chain and answerthe following: (MAY-2016)
a) What is biomagnification?
b) What are the consequences of biomagnification?

Answer:
a) Non bio degradable chemicals which accumulate in the body of organism and is passed on to the organisms belonging to the next trophic level, the increase in the concentration of toxicants at successive trophic level and finally concentration become high in last trophic level of the food chain.
b) 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 23.
Adequate waste management is an environment issue to be considered. Discuss the advantages of Eco-san toilet. (MAY-2016)
Answer:
it is a sustainable system for handling human excreta, using dry composting toilets.
This is a practical, hygienic, efficient and cost- effective solution to human waste disposal.

Question 24.
A common cause of deforestation is slash and burn agriculture. (MARCH-2017)
a) What is the common name attributed to such type of cultivation?
b) Explain how this type of cultivation is practised?
Answer:
a) phytoplankton stage
b) Submerged plant stage
c) Submerged free floating plant Stage
d) Reed swamp stage
f) Marsh – meadow stage
g) Scrub stage
h) Forest stage

Question 25.
Particulate matter in polluted air is removed by the application of electrostatic precipitator. Explain the working principle of lectrostatic precipitator. (MARCH-2017)
Answer:
At high voltage the electrons produced in an instrument 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. Electrostatic precipitator which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant.

Question 26.
Among the following which one Is used for reducing the emission of poisonous gases from automobiles (MAY-2017)
a) Landfills
b) Catalytic converter
c) Electrostatic precipitator
d) Earmuffs
Answer:
Catalytic converter

Question 27.
Nutrient enrichment in a fresh water lake leads to (MAY-2017)
eutrophication.
a) What happens during eutrophication?
b) How dissolved oxygen level is affected as a result of this?
Answer:
a) Due to accumulation of nitrate and phosphate into the lake, leads the rapid growth of algae, that changes the colour and quality of water.
It depletes the oxygen content of water and finally causes the death of aquatic organs.
b) Due the death and decay of algae, dissolved oxygen content is decreased in lake that causes the mortality of fish and other aquatic organs.