Biodiversity and Conservation Important Questions for CBSE Class 12 Biology Conservation of Biodiversity
1.Reasons for Conservating Biodiversity
There are various reasons for conservation of biodiversity. These can be grouped as:
(i) Narrowly Utilitarian Arguments
(a) Humans derive several direct economic benefits from nature such as food (cereals, pulses and fruits), firewood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins and perfumes) and products of medicinal utilities.
(b) More than 25% of drugs sold today are derived from plants and about 25,000 species of plants are used by native people as traditional medicines.
(ii) Broadly Utilitarian Arguments
(a) Biodiversity plays a major role in many ecosystem services that are provided by nature.
(b) Some of them are:
- Production of oxygen Amazon forest is estimated to produce, 20% of the total oxygen in the atmosphere through photosynthesis.
- Pollination Ecosystem provides pollinators like bees, bumblebees, birds and bats.
- Aesthetic pleasures like walking through thick woods, watching spring flowers in full bloom or waking up to koel or bulbul’s song in the morning.
(iii) Ethical Reasons
(a) Every species has an intrinsic value, even if it may not be of current or any economic value to us.
(b) We have a moral duty to care for their well being and pass on our biological legacy in good order to future generations.
2. Biodiversity Conservation Methods
The two basic approaches of biodiversity conservation are:
- In situ conservation (on-site conservation).
- Ex situ conservation (off-site conservation).
- Insitu conservation involves protection of species in their natural habitat.
(i) Biodiversity hot spots are regions with high levels of species richness and high degree of endemism (that is species confined to that region are not found anywhere else).
- The total number of biodiversity hot spots in the world are 34.
- These hot spots are regions of accelerated habitat loss.
- Three hot spots which cover India’s, biodiversity regions are Western Ghats and Sri Lanka, Indo-Bunna and
- These hot spots can reduce the ongoing mass extinctions by almost 30%.
(ii) Protected areas are ecologically unique and biodiversity rich regions. These are legally protected as biosphere reserves, national parks and sanctuaries.
- India has 14 biosphere reserves, 90 national parks and 448 wildlife sanctuaries.
- The first national park set up in India was Jim Corbett National Park.
(iii) Sacred groves are forest areas set aside, all the trees and wildlife within it are venerated and given total protection.
Some of the sacred groves in India are:
- Western Ghat regions of Karnataka and Maharashtra.
- Khasi and Jaintia Hills in Meghalaya.
- Aravalli Hills of Rajasthan.
- Sarguja, Chanda and Bastar areas of Madhya Pradesh.
2.Ex situ conservation involves placing of threatened animals and plants in special care units for. their protection.
(i) Zoological parks, botanical gardens and wildlife safari parks serves this purpose.
(ii) There are many animals that have become extinct in the wild but continue to be maintained in zoological parks.
(iii)
Cryopreservation
(preserving at -196°C) technique is used to preserve sperms, eggs, animal cell, tissue and embryos and to store them for longer times in gene banks, seed banks, etc.
(iv) In vitro propagation of plants is carried out by applying tissue culture method.
3.Conventions on biodiversity The conservation of biodiversity is a collective responsibility of all the nations.
(i) Historic convention on biological diversity (The Earth Summit) was held in Rio de Janerio in 1992. It called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilisation of its benefits.
(iii) The World Summit on sustainable development was held in Johannesburg, South Africa in 2002, as a follow up in which 190 countries pledged their commitment to achieve by 2010. As a result, a significant reduction in the current rate of biodiversity loss at global, regional and local levels is achieved.
- The Red List The IUCN maintains a document called Red List or Red Data Book of taxa that are facing the risk of extinction.
The IUCN Red List categories are:
- Extinct (EX) with no individuals remaining, e.g. javan tiger, dodo and woolly mammoth.
- Extinct in the wild (EW) only surviving in captivity or in locations outside its historic range, e.g. Hawaiian crow, Socorro dove and Scimitar Oryx.
- Critically endangered (CR) extremely high risk of extinction in the wild, g. mountain gorilla, Bactrian camel, California condor and white rhinoceros.
- Endangered (EN) high risk of extinction in the wild, e.g. blue whale, giant panda, snow leopard and tiger.
- Vulnerable (VU) high risk of endangerment in the wild, e.g. African elephant, cheetah, polar bear and hippopotamus.
- Near Threatened (NT) likely to become endangered in the near future, e.g. American bison, jaguar, okapi and tiger shark.
- Least Concern (LC) lowest risk, no immediate threat to survival, e.g. giraffe, brown bear, gray wolf, house mouse, emperor penguin and human.
Out of these, four categories of species are included under threatened species- critically endangered, endangered, vulnerable and lower risk species. Two more categories are also added to them. These are rare species and indeterminate species.
- Rare species (R) are species with naturally small populations, either localised or thinly scattered, which are always at risk from pests/pathogens/predators/ exotic species. Clouded leopard (Neofelis nebulosa) of Himalayas is a rare species.
- Indeterminate species are in danger of extinction but the reason is not known, e.g. 3-banded Armadillo of Brazil, short eared rabbit of Sumatra, Mexican prarie dog.
Previous Years Examination Questions
1 Mark Questions
1.Write the importance of cryopreservation in conservation of biodiversity. [Delhi 2011]
Ans. Gametes of threatened species can be preserved in viable and fertile conditions for long periods by cryopreservation.
2.Mention one application of pollen bank. How are pollen stored in a bank? [Delhi 2008C]
Ans. Pollen banks can be used to store pollen grains like seed banks. Stored pollen grains can be used in pollen breeding programmes. Pollen grains can be stored in liquid nitrogen -196°C for many years.
2 Marks Questions
3. State the uses of biodiversity in modern agriculture. [All India 2011]
Ans . Uses of biodiversity in modern agriculture are:
(i) Humans obtain food, fibres, medicines and many industrial products from plants.
(ii) Wild varieties of plants are used for breeding to obtain disease and pest resistant crops with many desirable traits.
(iii) By exploring molecular, genetic and species level diversity for economically important products, rich biodiversity can be obtained.
4. Differentiate between insitu and exsitu approaches of conservation of biodiversity. [All India 2011]
Ans . Differences between in situ and ex situ approaches of conservation of biodiversity are:___
5. Biodiversity must be conserved as it plays an important role in many ecosystem services that nature provides. Explain any two services of the ecosystem. [Delhi 2010]
Ans . The two ecosystem services are:
(i) Forest ecosystem, mitigates droughts and floods.
(ii) The wildlife help in pollination of crops.
6. Why certain region have been declared as biodiversity hot spots by environmentalists of the world? Name any two hot spot regions of India. [Delhi 2010]
Ans. Certain regions are declared hot spots by the environmentalists because these regions have very high levels of species richness and high degree of endemism. Hot spots of India are Western Ghats and Sri Lanka, Himalayas and Indo-Burma
3 Marks Questions
7. There are many animals that have become extinct in the wild but continue to be maintained in zoological parks. ‘
- What type of biodiversity conservation is observed in this case?
- Explain any other two ways which help this type of conservation. [Delhi 2014]
Ans. (i) The animals maintained in zoological parks is an example of ex situ conservation, as it involves threatened animals in special conditions, away from natural habitat, in order to protect them.
(ii) The other ways of maintaining the endangered animals or species by ex situ conservation are botanical gardens and wildlife safari parks.
8. White Bengal tigers are protected in special settings in zoological parks. Tiger reserves are maintained in Western Ghats.
- How do these two approaches differ from each other? Mention the advantages of each one.
- What is the significance of cryopreservation technique? [All India 2010C]
Ans. White Bengal tigers are protected in special settings in zoological parks. This is called ex situ conservation, while tiger reserves are maintained in Western Ghats. This is called in situ
(i) For differences between two approaches, i.e. in situ conservation and ex situ conservation and their advantages.
(ii) Using cryopreservation technique:
- Gametes of threatened species can be preserved in viable and fertile conditions for long.
- Plants are propagated by tissue culture method.
- Eggs can be fertilised in vitro.
5 Marks Questions
9. (i) Why is there a need to conserve biodiversity?
(ii) Name and explain any two ways that are responsible for the loss of biodiversity. [All India 2014]
Ans .(i) The biodiversity needs to be conserved because of three categories: .
- Narrow utilarian includes most of the resources required for our day-io-day life, e.g. food, oil, clothes, firewood, drugs and medicines, industrial products all are derived from nature, thus needs to be conserved to reap more benefits.
- Broadly utilarian includes most of the ecosystem services provided to us by nature. Such as release of oxygen and fixation of C0 2 by photosynthesis in plants, pollination and dispersal of seeds, etc. Therefore, for the continuation of these services biodiversity needs to be conserved.
- Ethical reasons as it becomes our moral duty to take care of all living species in our surroundings irrespective of their economic importance and pass this biological legacy to our future generations.
(ii) The two ways that are responsible for the loss of biodiversity are:
- Habitat loss and fragmentation of natural habitats due to the natural reasons or human activities and pollution results in degradation of habitats, thereby threatening the survival of many species concerned.
- Co-extinction also leads to loss of biodiversity as when a species becomes extinct, the plant and animal species associated with it in obligatory way also become extinct, e.g. when a host organism (fish) becomes extinct, the parasites exclusive to it also becomes extinct
10. (i) Why is there a need to conserve biodiversity?
(ii) Name and explain any two ways that are responsible for the loss of biodiversity. [All India 2014]
Ans. (i) The biodiversity needs to be conserved because of three categories: .
- Narrow utilarian includes most of the resources required for our day-io-day life, e.g. food, oil, clothes, firewood, drugs and medicines, industrial products all are derived from nature, thus needs to be conserved to reap more benefits.
- Broadly utilarian includes most of the ecosystem services provided to us by nature. Such as release of oxygen and fixation of C0 2 by photosynthesis in plants, pollination and dispersal of seeds, etc. Therefore, for the continuation of these services biodiversity needs to be conserved.
- Ethical reasons as it becomes our moral duty to take care of all living species in our surroundings irrespective of their economic importance and pass this biological legacy to our future generations.
(ii) Hot spots are regions exhibiting high degree of endemism and great species richness, therefore designating these areas as ‘biodiversity hot spots’ allows their maximum protection and reduce the ongoing extinction by about 30%.
Such hot spot regions in India are Western Ghats and Himalayas.
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