Biodiversity and Conservation Class 12 Important Questions and Answers Biology Chapter 15

Biodiversity and Conservation Class 12 Important Questions and Answers Biology Chapter 15

IMP QUE 12TH BIO
Published on By Amresh Academy

   

Class 12 Biology Chapter 15 Important Questions Biodiversity and Conservation

Question 1.
Identify A and B in the figure given below representing proportionate number of major vertebrate taxa. (Delhi 2014)
    
Answer:
In the mentioned diagram, among the major vertebrate taxa
A-represents mammals.
B-represents ambhibians.

Question 2.
Write the level of biodiversity represented by a mangroves. Give another examples falling in the same level. (Delhi 2014C)
Answer:
The mangroves represent biodiversity at ecological level. Other examples of ecological diversity are deserts, rainforests, coral reefs, etc.

    

Question 3.
Name the type of biodiversity represented by the following
(i) 1000 varieties of mangoes in India.
(ii) Variations in terms of potency and concentration of reserpine in Rauwolfia vomitoria growing in different regions of “Himalayas. (All India 2013)
Answer:
(i) Genetic diversity
(ii) Genetic diversity.

Question 4.
Name the type of biodiversity represented by the following
(i) 50000 different strains of rice in India,
(ii) Estuaries and alpine meadows in India. (Delhi 2013)
Answer:
(i) Genetic diversity
(ii) Ecological diversity.

Question 5.
Why is tropical environment able to support greater species diversity? (Delhi 2011C)
Answer:
Tropical latitudes have less seasonal variations and constant environment which promote niche and greater species diversity.

Question 6.
Eichhornia crassipes is an alien hydrophyte introduced in India. Mention the problem posed by this plant. (All India 2010C)
Answer:
Water hyacinth (Eichhomia) introduced in India is threatening the existing aquatic life in ponds and lakes, etc., as it clogs the stagnant waterbodies very fast, thus, the native species are threatened.

Question 7.
The Amazon rainforest is referred to as the lungs of planet. Mention any one human activity which causes loss of biodiversity in this region. (All India 2010C)
Answer:
Human activities causing loss of biodiversity in Amazon rainforest are as follows

  • Many plants are cut in Amazon rainforest for cultivation of soybeans.
  • Forests are converted to grasslands for raising beef cattle.

Question 8.
India has more than 50000 strains of rice. Mention the level of biodiversity it represents. (Delhi 2010; Outside Delhi 2010)
Answer:
India has more than 50000 strains of rice which shows the genetic level of biodivesity of rice.

Question 9.
How is an alien species invasion considered as one of the cause of biodiversity loss? Support you answer with the help of an example. (All India 2019)
Or
Alien species invasions is one of the causes of biodiversity loss. Explain with the help of an example. (All India 2012C)
Or
With the help of an example, explain how alien species invasion causes biodiversity loss (Delhi 2011)
Or
Alien species are a threat to native species. Justify taking examples of an animal and a plant alien species. (All India 2010)
Or
Sometimes alien species affect the indigenous organisms leading to their extinction. Substantiate this statement with the help of any two examples. (Delhi 2010C)
Answer:
Alien species become invasive, compete with the native species and cause extinction of indigenous species.

  • Introduction of Nile perch into Lake Victoria leads to extinction of more than 200 species of cichlid fish in that lake.
  • Carrot grass (Parthenium) and Lantana introduced in our country have become invasive and cause environmental damage. They pose a threat to the native species of plants in our forests.

Question 10.
Substantiate with the help of one example that in an ecosystem mutualists.
(i) tend to coevolve and
(ii) are also one of the major causes of biodiversity loss. (Delhi 2019)
Answer:
(i) In nature mutualists often co-evolve such as mediterranean orchid Ophrys. Ophrys employs sexual deceit to get pollinated by a species of bee. One petal of flower resembles to female bee. If female bee changes its colour pattern even slightly the success of pollination will be reduced unless orchid flower coevolves to maintain resemblance with female bee.

(ii) Coextinction is the one of the Evil Quartet in which organism with obligatory relationship like plant pollinator mutualism will result in extinction of one partner, if other is eliminated in nature.

Question 11.
Identify the areas labelled i, ii, iii and iv in the pie chart given below representing the biodiversity of plants showing their proportionate number of species of major taxa. (2018C)
    
Answer:

  • Lichens
  • Algae
  • Fungi
  • Mosses

Question 12.
Mention the kind of biodiversity of more than a 1000 varieties of mangoes in India represent. How is it possible? (Delhi 2016)
Answer:
The different varieties of mangoes in India represent genetic diversity.
It occurs because India lies within tropical latitudes where, the environment is constant and predictable. Also, more solar energy is available which leads to higher productivity.

    

Question 13.
List four causes of biodiversity loss. (Delhi 2014C)
Answer:
The four causes of biodiversity loss are as follows

  • Habitat loss and fragmentation
  • Overexploitation
  • Alien species invasions
  • Coextinctions.

Question 14.
What is meant by alien species invasion? Name one plant and one animal alien species that are a threat to our Indian native species. (All India 2013)
Answer:
Intentional or chance introduction of exotic species into new Islands or countries by man is called alien species invasion.

For example, Nile perch introduced into Lake Victoria in East Africa caused loss of more than 200 species of cichlid fish. Plant alien species-Lantana camara and animal alien species-Clarias gariepinus have posed threat to our Indian native species.

Question 15.
“Stability of a community depends on its species richness.’ Write how did David Tilman show this experimentally. (Outside Delhi 2013)
Answer:
The stability of a community depends on species richness. This was confirmed by David Tilman. Through his ecology experiments Tilman showed

  • The plots with more species showed less year-to-year variations in total biomass.
  • Plots with increased diversity showed higher productivity.

Question 16.
Where would you expect more species biodiversity in tropics or in polar regions? Give reasons in support of your answer. (Outside Delhi 2013)
Or
Giving two reasons explain why there is more species biodiversity in tropical latitudes than in temperate ones. (All India 2010)
Answer:
Biodiversity is more in tropical latitudes than in temperate or in polar regions. The reasons are (any two)

  • Speciation is a function of time. The temperate regions were subjected to frequent glaciation in the past, while the tropics have remained undisturbed and so had longer time to evolve more species diversity.
  • More solar radiation is available in tropical region. This leads directly to more productivity and indirectly to greater species diversity.
  • The environment of tropics is less seasonal and relatively more constant and predictable, which encourages niche specialisation and species diversity.

Question 17.
State the use of biodiversity in modern agriculture. (Outside Delhi 2011)
Answer:
The use of biodiversity in agriculture is immense. It is a source of hybrids, GM plants, biopesticides, organic farming, biofertiliser, improved varieties of plants, disease resistant plants. It also promotes sustainable management of agricultural resources, conservation and farming of all wild and native varieties of plants, etc.

Question 18.
Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species. (Delhi 2011)
Answer:
Overexploitation of natural resources or over hunting of animals has led to extinction of particular species, e.g. Steller’s sea cow and passenger pigeon.
Other examples of human driven extinction include Dodo bird due to habitat fragmentation.

Question 19.
The given graph shows species-area relationship. Write the equation of the curve A and B explain. (All India 2011)
    
Answer:
The equation for the curve A is S = C4Z where, S- Species richness,
A – Area,
C – Y-intercept,
Z – Slope of line (regression coefficient)
(i) Alexander von Humboldt observed that within a region, species richness increased with increasing explored area, but only up to a limit.
(ii) The relation between species richness and area for a wide variety of taxa like angiosperms, birds, fishes, etc., turns out to be a rectangular hyperbola.

Question 20.
Explain, taking one example, the effect of coextinction on biodiversity. (Delhi 2011c)
Answer:
Coextinction means that when a species is going to become extinct, the plant and animal species associated with it in an obligatory relationship also gets extinct. For example, coevolved plant-pollinator mutualism as in case of Pronuba yuccasella and Yucca. If one partner is on the verge of extinction, the other partner will also get extinct.

Question 21.
How does overexploitation of beneficial species affect biodiversity? Explain with the help of one example. (Delhi 2011C)
Answer:
Human beings when overexploite any plant/animal species, it affects their population size. The marine fish population around the world are declining due to overharvesting. It results in endangering the continued existence of some commercially important species. In the last 500 years, extinction of Stellar’s sea cow and passenger pigeon were due to the overexploitation of these animals by humans.

Question 22.
In the biosphere, immense biological diversity exists at all levels of biological organisation. Explain any two levels of biodiversity. (All India 2010)
Answer:
Levels of Biodiversity in Biosphere

  • Genetic diversity It refers to the diversity of genes within a species. For example, there are more than 50000 genetically different strains of rice in India.
  • Species diversity It refers to the number of different species within a given region. For example. Western Ghats have a greater amphibian species diversity than Eastern Ghats.

    

Question 23.
List the features that make a stable biological community. (All India 2010)
Answer:
Features of Stable Biological Community

  • It should not show much variation in productivity from year-to-year.
  • It should be resistant or resilient to occasional disturbances both natural and man-made.
  • It must be resistant to invasions of alien species. (Any two)

Question 24.
Write any two hypothesis put forth by ecologists explaining the existence of greater biodiversity in tropical regions than in temperate regions. (Foreign 2010)
Answer:
For two hypothesis put forth by ecologists explaining the existence of greater biodiversity in tropical regions, than in temperates. Refer to Answer No. 16.

Question 25.
Explain any two most important levels of biological organisation showing biodiversity with the help of an example each. (Delhi 2019, 2018)
Or
Explain the levels of biodiversity at genetic, specific and ecological levels with the help of one example each. (Delhi 2016)
Answer:
Genetic diversity A single species shows diversity at the genetic level over its distributional range. For example, the genetic variation shown by the plant Rauwolfia vomitoria growing in the different Himalayan ranges might be due to its potency and concentration of reserpine.

Species diversity It is the diversity at species level and it is affected by species richness and species evenness. For example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats.
Ecological diversity It is the diversity at ecological level and is dependent on genetic and species diversity.
At the ecosystem level, India shows diversity with its deserts, rainforests, mangroves, coral reefs and alpine meadows.

Question 26.
(i) India has greater ecosystem diversity than Norway. Do you agree with the statement? Give reasons in support of your answer.
(ii) Write the difference between genetic biodiversity and species biodiversity that exists at all the levels of biological organisation. (2018)
Answer:
(i) India is one of the twelve megadiversity regions of the world with 8.1% of genetic resources of the world. Since, India is placed in the tropical part of the world it exhibits more species diversity than the regions of temperate zones.
India, with much of its land area in the . tropical latitudes, has more than 1200 species of.birds. Greenland, Norway is away from tropics, so it exhibits less biodiversity.

(ii) Differences between genetic and species biodiversity are as follows

Genetic DiversitySpecies Diversity
It is related to the number of genes and their alleles found in organisms.It is related to the number and distribution of species found in an area.
It is a trait of a species.It is a trait of community.
It influences biotic adaptability and distribution of species in diverse habitats.It influences interactions and stability of the community.

Question 27.
Name and describe any three causes of biodiversity losses. (Delhi 2017)
Or
Name and explain any two ways that are responsible for the loss of biodiversity. (Foreign 2014)
Causes of biodiversity losses are as follows

  • Habitat Loss and Fragmentation : The main cause of extinction of species is the v destruction of their habitat. For example, tropical rainforests once covering more than 14% of the land surface, now cover only 6% of land area.
  • Overexploitation of natural resources byhumans results in degradation and extinction of the resources. For example, Steller’s sea cow, passenger pigeon and many marine fishes have become extinct in last 500 years.

Question 28.
Write the importance of species diversity to the ecosystem. Support your answer with the finding of Tilman. (Delhi 2016)
Answer:

  • Ecologists for many years, believe that communities with more species are more stable than those with less species. Greater species diversity ensures natural sustainability for all life forms.
  • David Tilman’s long term ecosystem experiments using outdoor plots provided answers to stability of a biological community and species richness in that community. Tilman found that plots with more species showed less year-to-year variation in total biomass. He also showed in his experiments that increased diversity contributed to higher productivity.

Question 29.
Since the origin of life on earth, there were five episodes of mass extinction of species.
(i) How is the ‘Sixth extinction’, presently in progress, different from the previous episodes?
(ii) Who is mainly responsible for ‘Sixth Extinction’?
(iii) List any four points that can help to overcome this disaster, outside (Delhi 2014)
Answer:
(i) The current species extinction rate is estimated to be 100-1000 time faster than in the pre-human era.
(ii) All activities performed by human beings for survival and maintenance of their lifestyle.
(iii) Point that can help to overcome this disaster are as follows

  • Preventing habitat loss and fragmentation.
  • Checking overexploiting.
  • Preventing alien species invasion.
  • Preventing coextinction.
  • Conservation/protection of species.

    

Question 30.
The following graph shows the species-area relationship. Answer the following questions as directed.
(i) Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him.
(ii) Write the situations as discovered by the ecologists when the value of Z (slope of the line) lies between
    
(a) 0.1 and 0.2
(b) 0.6 and 1.2
What does Z stand for?
(iii) When would the slope of the line B become steeper? (All India 2014)
Answer:
(i) Alexander von Humboldt studied the relationship shown in above graph. He observed that the species richness in an area increased with an increase in exploring area, up to a certain limit only.
(ii) (a) Ecologists have observed that when the value of Z lies between 0.1-0.2 then the Species are considered for a small or average area.
(b) When the value of Z lies between 0.6-1.2, the area considered is very large. Z represents the slope of the line, i.e. regression coefficient.
(iii) The slope of the line B will become steeper when very large areas such as continents are considered for species area relationship.

Question 31.
Explain giving three reasons, why tropics show greatest levels of species diversity? (All India 2014)
Or
List the reasons that account for the greater biological diversity in tropics. (Foreign 2012)
Answer:
For reasons why tropics have greatest species diversity. Refer to Answer No. 16.

Question 32.
Alien species are highly invasive and are a threat to indigenous species. Substantiate this statement with any three examples. (All India 2012)
Answer:
For Allien species invasion. Refer to Answer No. 27 (iii).

Question 33.
Taking one example each of habitat loss and fragmentation, explain how are the two responsible for biodiversity loss. (All India 2012)
Answer:
For fragmentation and habitat loss, Refer to Answer No. 27 (i).

Question 34.
(i) Explain the species-area relationship using the graphical representation given below.
    
(ii) Explain giving reasons why there is greater biodiversity in tropical regions of the earth. (All India 2012c)
Answer:
(i) Alexender von Humboldt studied species-area relationship. He observed that within a region, the species richness increased with increasing area upto a certain limit.
(ii) Ecologists have discovered that the value of Z lies in the range of 0.1-0.2 regardless of taxonomic group or region. When species-area relationship is considered for a large area like a whole continent, regression coefficient Z or slope of the line becomes steeper with Z-values in the range of 0.6-1.2.

For example, for fruit eating birds and mammals in tropical forests of different continent, the slope is found to be 1.15.

Question 35.
Explain by giving example, how coextinction is one of the causes of loss of biodiversity. List the other three causes also (without description). (foreign 2011)
Answer:
Coextinction is one of the causes of loss of biodiversity as when a species becomes extinct, the plant and,animal species associated with it in an obligatory manner, also become extinct.
For example,

  • In plant pollinator mutualism, extinction of one results in the extinction of other.
  • If a host fish becomes extinct, the unique parasites depending on it would also become extinct.

The other causes of loss of biodiversity are

  • Habitat loss fragmentation
  • Overexploitation
  • Invasion of alien species.

Question 36.
Explain rivet popper hypothesis. Name the ecologist who proposed it. (Foreign 2011)
Answer:
Rivet Popper Hypothesis

  • The hypothesis was proposed by Paul Ehrlich.
  • In an airplane (ecosystem), all parts are joined together using thousands of rivets (species).
  • If every passenger travelling in it, starts popping a rivet to take home (causing a species to become extinct), it may not affect the flight safety (proper functioning of ecosystem) initially, but as more and more rivets are removed, the plane becomes dangerously weak after some time.
  • Further, loss of rivets on the wings. (Key species that drive major ecosystem function) is obviously a more serious threat to flight safety than loss of a few rivets on the seats or windows inside the plane.

Question 37.
Why Western Ghats in India have been declared as biological hotspot? (Delhi 2015)
Answer:
Western Ghats have been declared as biological hotspot due to it is rich biodiversity and ecological condition favoring many species of plants and animals. Many endemic species of amphibians, reptiles and fishes are found in these regions.

Question 38.
Write the importance of cryopreservation in conservation of biodiversity. (Delhi 2011)
Answer:
The importance of cryopreservation in conservation of biodiversity is that gametes of threatened species can be preserved in viable and fertile conditions for long periods by cryopreservation.

Question 39.
Suggest two practices giving one example of each, that help to protect rare or threatened species. (All India 2017)
Answer:
Practices that help to protect rare threatened species are as follows

  • In situ (on-site) conservation involves protection of species in their natural habitat. In involves biosphere reserves, national parks, wildlife sanctuaries, sacred groves, etc,
  • Ex situ (off-site) conservation involves placing threatened animals and plants in special care units for their protection. Zoological parks, botanical gardens and wildlife safari parks serve this purpose.

    

Question 40.
Why are sacred groves highly protected? (All India 2016)
Answer:
Sacred groves are small patches of forests with special religious importance in a particular culture.

  • These are also mythologically important.
  • These are undisturbed forests without any human interventions.
  • These are highly protected hence, they include a number of rare, endangered and endemic species. (2)

Question 41.
list any four techniques where the principle of ex situ conservation of biodiversity has been employed. (All India 2015)
Answer:
Four techniques where principle of ex situ conservation of biodiversity has been employed are

  • Tissue culture
  • Cryopreservation
  • Botanical gardens
  • Zoological parks.

Question 42.
Why is there a need to conserve biodiversity? (Foreign 2014)
Answer:
The main reasons to conserve biodiversity are as follows

  • Narrowly utilitarian reasons These are obvious reasons as human derives multiple economic benefits like food, fibre, medicinal and industrial products, etc.
  • Broadly utilitarian reasons Biodiversity plays a major role in providing ecosystem services which cannot be given a price-tag, e.g. oxygen, pollination, aesthetic pleasure, etc.

Question 43.
State the uses of biodiversity in modern agriculture. (All India 2011)
Answer:
Uses of biodiversity in modern agriculture are –

  • Humans obtain food, fibres, medicines and many industrial products from plants.
  • Wild varieties of plants are used for breeding to obtain disease and pest resistant crops with many desirable traits.
  • By exploring molecular, genetic and species level diversity for economically important products, rich biodiversity can be obtained.

Question 44.
Differentiate between in situ and ex situ approaches of conservation of biodiversity. (All India 2011)
Answer:
Differences between in situ and ex situ approaches of conservation of biodiversity are as follows

In situ conservationEx situ conservation
This method involves protection of endangered species in their natural habitat.It involves placing of threatened animals and plants in special care unit out of their natural habitat for their protection.
It helps in recovering populations in the surroundings where they have developed their distinct features.It helps in recovering populations or preventing their extinction under stimulated conditions that closely resemble their natural habitats.
e.g. national parks, biosphere reserves, wildlife sanctuaries, etc.e.g. botanical gardens, zoological parks.

Question 45.
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)
Answer:
The two ecosystem services are

  • Forest ecosystem mitigates droughts and floods and provides oxygen.
  • The wildlife helps in pollination of crops, without which fruits/seeds are not produced.

Question 46.
Why certain regions have been declared as biodiversity hotspots by environmentalists of the world? Name any two hotspot regions of India. (Delhi 2010)
Answer:
Certain regions are declared hotspots by the environmentalists, because these regions have very high levels of species richness and high degree of endemism.
Hotspots of India are Western Ghats and Sri Lanka, Himalayas and Indo-Burma.

Question 47.
White Bengal tigers are protected in special settings in zoological parks. Tiger reserves are maintained in Western Ghat.
(i) How do these two approaches differ from each other? Mention the advantages of each one.
(ii) What is the significance of cryopreservation technique? (All India 2010C)
Answer:
(i) Zoological parks are man-made places where endangered species are kept and taken care of by specilised skilled persons. It helps to . prevent species extinction.
Tiger reserves are natural habitats of tigers in which they are protected in natural habitat. It helps in recovering population of the species where they have developed their distinctive features.
(ii) Cryopreservation is ex situ conservation technique in which tissues, organs, embryos, seeds gametes, pollens, etc., are stored at very low temperature of -196°C for future use.

    

Question 48.
List six advantages of ‘ex situ’ approach to conservation of biodiversity. (Delhi 2019)
Answer:
Ex situ conservation strategies help

  • To conserve those animals that have become extinct in wild, but can be maintained in zoological parks.
  • To preserve gametes of threatened species in viable condition through cryopreservation.
  • To propagate threatened plants via tissue culture.
  • To grow plants with recalcitrant seeds in orchards where all possible varieties are maintained.
  • To conserve seed of commercially important plants in seed banks.
  • To save endangered or threatened plant that needs urgent measure to save it from extinction in botanical gardens.

Question 49.
Explain the ‘ex situ conservation’ of biodiversity. How is the in situ conservation different from it? (2018C)
Answer:
For ex situ conservation, Refer to Answer No. 3 (ii) and for difference Answer No. 8.

Question 50.
In situ conservation can help endangered threatened species. Justify the statement. (Delhi 2017)
Answer:
In situ conservation involves the protection of species in their natural habitats. It helps in the conservation of threatened/endangered species via following means

  • Biodiversity hotspots are regions with high levels of species richness and high degree of endemism (i.e. species confined to that region are not found anywhere else). Hotspots cover less than 2% of the earth’s land area.
  • Protected areas are ecologically unique and biodiversity rich regions. These are legally protected as biosphere reserves, national parks and sanctuaries.
  • Sacred groves are forest areas set aside, all the trees and wildlife within it are venerated . and given total protection. These are religious and cultural places, which are protected.

Question 51.
Why should biodiversity be conserved? Explain giving three reasons. (Outside Delhi 2016C)
Answer:
Biodiversity should be conserved for the following reasons

  • The broadly utilitarian argument says that biodiversity plays a major role in many ecosystem services that nature provides.
  • The narrow utilitarian argument says that humans derive countless direct economic benefits from nature and products of medicinal importance.
  • The ethical argument for conserving biodiversity relates to what we owe to millions of plant, animal and microbe species with whom we share this planet.

Question 52.
Many plant and animal species are on the verge of their extinction because of loss of forest land by indiscriminate use by the humans. As a biology student what method would you suggest along with its advantages that can protect such threatened species from getting extinct. (Delhi 2015)
Answer:
As a biology student, I would suggest ex situ conservation approach for such animals. It involves placing the threatened animals and plants in special care units for their protection. It includes off-site collections (botanical gardens, zoological parks, etc.) and (gene banks, seed banks, tissue culture, etc).

Advantages of ex situ conservation are

  • Off-site collection can be used to restock depleted population, reintroduce species in the wild and restore degraded habitats.
  • It is useful in maintaining a large number of genotypes in small area, rapid multiplication of endangered species, through tissue culture, etc.

Question 53.
Compare narrowly utilitarian and broadly utilitarian approaches to conserve biodiversity, with the help of suitable examples. (Foreign 2015)
Answer:
Comparison between narrowly utilitarian and broadly utilitarian approaches are as follows

Narrowly utilitarian approachBroadly utilitarian approach
It includes most of the resources required for our day-to-day life.It includes most of the ecosystem services provided to us by nature.
e.g. food, oil, clothes, wood and drugs.e.g. release of O2 and fixation of CO2.

Question 54.
There are many animals that have become extinct in the wild but continue to be maintained in zoological parks.
(i) What type of biodiversity conservation is observed in this case?
(ii) Explain any other two ways which help this type of conservation. (Delhi 2014)
Answer:
(i) Zoological parks are an example of ex situ conservation, in which threatened animals are kept 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 cryopreservation.

In botanical garderns, plants are grown in special conditions. Threatened and critically endangered plant species are grown here.
In cryopreservation, gametes and seeds of threatened species are preserved in viable condition at the temperature of around -196° C.

Question 55.
The sacred groves of Aravalli Hills and Ooty botanical garden both aim at biodiversity conservation. How do they differ in their approaches? Explain. (All India 2013C)
Answer:
Sacred groves are undisturbed forest patches, surrounded by highly degraded landscapes where not even a “single human activity is allowed, e.g. sacred groves of Aravalli hill is protecting many endemic species.
In botanical gardens, the plants are raised outside their natural habitat under the supervision of skilled persons.

    

Question 56.
What are the two types of desirable approaches to conserve biodiversity? Explain with examples bringing out the difference between the two types. (Delhi 2012, All India 2012)
Answer:
Conservation of biodiversity meant the preservation of existing variable forms of life in their natural habitat, while deriving sustainable benefits from nature. It is done in situ (on-site) and ex situ (off-site). In situ preservation and conservation always aim to protect organisms in their natural habitats (e.g. sacred groves, biosphere reserves).

Ex situ conservation helps to protect threatened plants and animals. In this method, these organisms are placed outside the natural habitat and are promoted to reproduce.

Question 57.
(i) Why should we conserve biodiversity? How can we do it?
(ii) Explain the importance of biodiversity hotspots and sacred groves. (Delhi 2016)
Answer:
(i) For reasons, Refer to Answer No. 15 and for methods, Refer to Answer No. 18.
(ii) Importance of biodiversity hotspots and sacred groves Biodiversity hotspots are the regions of accelerated habitat loss. These can reduce the ongoing mass extinctions by almost 30%. Sacred groves are important in biodiversity conservation, as these are, naturally protected by the native population without much effort. In Meghalaya, the sacred groves are the last refuges for large number of rare and threatened plants.

Question 58.
(i) Explain the narrow utilitarian, broadly utilitarian and ethical arguments in favour of conservation of biodiversity.
(ii) How is designation of certain areas as hotspots a step towards biodiversity conservation? Name any two hotspots in India. (Delhi 2014C)
Answer:
(i) Refer to Answer No. 15.
(ii) Hotspots are regions exhibiting high degree of endemism and great species richness, therefore designating these areas as ‘biodiversity hotspots’ allows their maximum protection and reduce the ongoing extinction by about 30%. Such hotspot regions in India are Western Ghats and Himalayas.

Question 59.
(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)
Answer:
(i) The biodiversity needs to be conserved because of three reasons

  • Narrow utilitarian includes most of the resources required for our day-to-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 utilitarian includes most of the ecosystem services provided to us by nature. Such as release of oxygen and fixation of C02 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.
  • Coextinction 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 become extinct.

Question 60.
(i) Taking one example each of habitat loss and fragmentation, explain how are the two responsible for biodiversity loss.
(ii) Explain two different ways of biodiversity conservation. (Outside Delhi 2012)
Answer:
(i) (a) When large-sized habitats are broken or fragmented due to human settlements, building of roads, digging of canals, etc., animals requiring large territories and some animals with migratory habitats are badly affected.
(b) The Amazon rainforest (called the ‘lungs of the planet’) is being cut and cleared for cultivation of soybean or for conversion into grasslands for raising beef cattle.

(ii) There are two basic approaches for conservation of biodiversity
(a) In situ conservation (on-site conservation)
(b) Ex situ conservation (off-site conservation)

In situ conservation: It is the conservation and protection of biodiversity in its natural habitat.
It helps in recovering population in the surroundings where they have developed their distinctive features.
Example National parks, biosphere reserves, wildlife sanctuaries.

Ex situ conservation: It is the conservation of selected rare plants and animals in places outside their natural habitat.
It helps in recovering population or preventing their extinction under conditions that closely resemble their natural habitats.
Example Botanical gardens, zoological parks, wildlife safari parks, gene banks, etc.

Question 61.
A construction worker was not allowed to cut trees in a village due to protests made by villagers that the trees were sacred to them. Would you support them? What values do you gather from this instance?
Answer:
Yes, I would support them. The sacred groves are protected areas which are of religious and cultural value to native people.
Values shown by villagers are care and concern towards environment and courage.

    

Question 62.
During a class tour to a botanical garden, Mamta saw that many plant species were present there, which are no more found in the wild. She asked her teacher about how these rare species cultivated and protected in such areas?
(i) Botanical gardens and zoos, etc., represent which mode of biodiversity conservation?
(ii) Mention the factors responsible for the extinction of biodiversity.
(iii) What values do you observe in Mamta?
Answer:
(i) Ex situ mode of conservation, where threatened animals and plants are placed in special care units.
(ii) Overexploitation of resources, fragmentation of habitats and introduction of alien species with native flora and fauna.
(iii) Environment friendly, intelligent, observant and curious.

Label :
Amresh Academy

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