Text Book Back Questions and Answers - Chapter 8 Environmental Issues 12th Biology Botany Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

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On April 24, 2024, 11:35 AM

Environmental Issues
Text Book BackQuestions and Answers
Question 1.
Which of the following would most likely help to slow down the greenhouse effect?
(a) Converting tropical forests into grazing land for cattle.
(b) Ensuring that all excess paper packaging is buried to ashes.
(c) Redesigning landfill dumps to allow methane to be collected.
(d) Promoting the use of private rather than public transport.
Answer:
(d) Promoting the use of private rather than public transport.
Question 2.
With respect to Eichhornia
Statement A: It drains off oxygen from water and is seen growing in standing water.
Statement B: It is an indigenous species of our country.
(a) Statement A is correct and Statement B is wrong.
(b) Both Statements A and B are correct.
(c) Statement A is correct and Statement B is wrong.
(d) Both statements $\mathrm{A}$ and $\mathrm{B}$ are wrong.
Answer:
(a) Statement A is correct and Statement B is wrong.
Question 3.
Find the wrongly matched pair.
(a) Endemism - Species confined to a region and not found anywhere else.
(b) Hotspots - Western ghats
(c) Ex-situ Conservation - Zoological parks
(d) Sacred groves - Saintri hills of Rajasthan
(e) Alien sp Of India - Water hyacinth
Answer:
(d) Sacred groves - Saintri hills of Rajasthan

Question 4.
Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancer?
(a) Ammonia
(b) Methane
(c) Nitrous oxide
(d) Ozone
Answer:
(d) Ozone
Question 5.
One green house gas contributes $14 \%$ of total global warming and another contributes $6 \%$. These are respectively identified as
(a) $\mathrm{N}_2 \mathrm{O}$ and $\mathrm{CO}_2$
(b) $\mathrm{CFCs}$ and $\mathrm{N}_2 \mathrm{O}$
(c) $\mathrm{CH}_4$ and $\mathrm{CO}_2$
(d) $\mathrm{CH}_4$ and $\mathrm{CFCS}$
Answer:
(b) $\mathrm{CFCs}$ and $\mathrm{N}_2 \mathrm{O}$
Question 6.
One of the chief reasons among the following for the depletion in the number of species making endangered is
(a) over hunting and poaching
(b) green house effect
(c) competition and predation
(d) habitat destruction
Answer:
(d) habitat destruction
Question 7.
Deforestation means
(a) growing plants and trees in an area where there is no forest
(b) growing plants and trees in an area where the forest is removed
(c) growing plants and trees in a pond
(d) removal of plants and trees
Answer:
(d) removal of plants and trees

Question 8 .
Deforestation does not lead to
(a) Quick nutrient cycling
(b) Soil erosion
(c) alternation of local weather conditions
(d) Destruction of natural habitat weather conditions
Answer:
(a) Quick nutrient cycling
Question 9.
The unit for measuring ozone thickness
(a) Joule
(b) Kilos
(c) Dobson
(d) Watt
Answer:
(c) Dobson
Question 10.
People's movement for the protection of environment in Sirsi of Karnataka is
(a) Chipko movement
(b) Amirtha Devi Bishwas movement
(c) Appiko movement
(d) None of the above
Answer:
(c) Appiko movement
Question 11.
The plants which are grown in silivpasture system are
(a) Sesbania and Acacia
(b) Solenum and Crotalaria
(c) Clitoria and Begonia
(d) Teak and sandal
Answer:
(a) Sesbania and Acacia
Question 12.
What is ozone hole?
Answer:
The decline in the thickness of the ozone layer over restricted area is called Ozone hole.

Question 13.
Give four examples of plants cultivated in commercial agroforestry.
Answer:
Casuarina, Eucalyptus, Teak, Malai vembu.
Question 14.
Expand CCS.
Answer:
Carbon Capture and Storage.
Question 15.
Hpw do forests help in maintaining the climate?
Answer:
Forests play a major role in regulating the $\mathrm{CO}_2$ level in the atmosphere. As the result global warming in highly reduced.
Question 16.
How do sacred groves help in the conservation of biodiversity?
Answer:
These are the patches or grove of cultivated trees which are community protected and are based on strong religious belief systems which usually have a significant religious connotation for protecting community. Each grove is an abode of a deity mostly village God Or Goddesses like Aiyanar or Amman.
448 grooves were documented throughout Tamil Nadu, of which 6 groves (Banagudi shola, Thirukurungudi and Udaiyankudikadu, Sittannnavasal, Puthupet and Devadanam) were taken up for detailed floristic and faunistic studies. These groves provide a number of ecosystem services to the neighbourhood like protecting watershed, fodder, medicinal plants and micro climate control.
Question 17.
Which one gas is most abundant out of the four commonest greenhouse gases? Discuss the effect of this gas on the growth of plants?
Answer:
Carbondioxide is the most abundant greenhouse gas. Increase in $\mathrm{CO}_2$ level in the air decreases the uptake of nitrogen components leading to protein deficiency and chlorophyll formation.
Question 18.
Suggest a solution to water crisis and explain its advantages.
Answer:
Rainwater harvesting is the accumulation and storage of rain water for reuse in-site rather than 

allowing it to run off. Rainwater can be collected from rivers, roof tops and the water collected is directed to a deep pit. The water percolates and gets stored in the pit. RWH is a sustainable water management practice implemented not only in urban area but also in agricultural fields, which is an important economical cost effective method for the future. Environmental benefits of Rain Water Harvesting:
1. Promotes adequacy of underground water and water conservation.
2. Mitigates the effect of drought.
3. Reduces soil erosion as surface run-off is reduced.
4. Reduces flood hazards.
5. Improves groundwater quality and water table / decreases salinity.
6. No land is wasted for storage purpose and no population displacement is involved.
7. Storing water underground is an eco-friendly measure and a part of sustainable water storage strategy for local communities.
Question 19.
Explain afforestation with case studies.
Answer:
Afforestation is planting of trees where there was no previous tree coverage and the conversion of non-forested lands into forests by planting suitable trees to retrieve the vegetation. Example: Slopes of dams afforesed to reduce water run-off, erosion and siltation. It can also provide a range of environmental sendees including carbon sequestration, water retention. The Man who Single Handedly Created a Dense Forest

Jadav "Molai" Payeng (bom 1963) is an environmental activist has single-handedly planted a forest in the middle of a barren wasteland. This Forest Man of India has transformed the world's largest river island, Majuli, located on one of India's major rivers, the Brahmaputra, into a dense forest, home to rhinos, deers, elephants, tigers and birds. And today his forest is larger than Central Park.

Former vice-chancellor of Jawahar Lai Nehru University, Sudhir Kumar Sopory named Jadav Payeng as Forest Man of India, in the month of October 2013. He was honoured at the Indian Institute of Forest Management during their annual event Coalescence. In 2015, he was honoured with Padma Shri, the fourth highest civilian award in India. He received honorary doctorate degree from Assam Agricultural University and Kaziranga University for his contributions.

Question 20.
What are the effects of deforestation and benefits of agroforesty?
Answer:
Effects of deforestation:
1. Burning of forest wood release stored carbon, a negative impact just opposite of carbon sequestration.
2. Trees and plants bind the soil particles. The removal of forest cover increases soil erosion and decreases soil fertility. Deforestation in dry areas leads to the formation of deserts.
3. The amount of runoff water increases soil erosion and also creates flash flooding, thus reducing moisture and humidity.
4. The alteration of local precipitation patterns leading to drought conditions in many regions. It triggers adverse climatic conditions and alters water cycle in ecosystem.
5. It decreases the bio-diversity significantly as their habitats are disturbed and disruption of natural cycles.
6. Loss of livelihood for forest dwellers and rural people.
7. Increased global warming and account for one-third of total $\mathrm{CO}_2$ emission.
8. Loss of life support resources, fuel, medicinal herbs and wild edible fruits.
Benefits of agroforestry:
1. It is an answer to the problem of soil and water conservation and also to stabilise the soil (salinity and water table) reduce landslide and water run-off problem.
2. Nutrient cycling between species improves and organic matter is maintained.
3. Trees provide micro climate for crops and maintain $\mathrm{CO}_2$ balanced, atmospheric temperature and relative humidity.
4. Suitable for dry land where rainfall is minimum and hence it is a good system for alternate land use pattern.
5. Multipurpose tree varieties like Acacia are used for wood pulp, tanning, paper and firewood - industries.
6. Agro-forestry is recommended for the following purposes. It can be used as Farm Forestry for the extension of forests, mixed forestry, shelter belts and linear strip plantation.