Biodiversity and conservation important questions

1. Western Ghats have a large number of plant and animal species that are not found anywhere else. Which of the following terms will you use to notify such species?

(a) Endemic (b) Vulnerable (c) Threatened (d) Keystone

Answer: (a)

2. Which is the National Aquatic Animal of India?

(a) Blue whale (b) Sea-horse (c) Gangetic shark (d) River dolphin

Answer: (d): River dolphin, found in holy river Ganga, Brahmaputra, Indus and their tributaries, is the National aquatic animal of India. Presence of river dolphin in Ganga indicates pure and fresh water.

3. Given below is representation of the extent of global diversity of vertebrates. What groups does the portions represent?

A B C D E

(a) Birds Reptiles Fishes Mammals Amphibians

(b) Mammals Birds Fishes Amphibians Reptiles

(d) Fishes Mammals Birds Reptiles Amphibians

Answer: (d)

4. Given here is a pie chart representation of the extent of global diversity of invertebrates. What groups the four portions (A-D) represent respectively?

A B C D

(a) Insects Crustaceans Other animal groups Molluscs

(b) Crustaceans Insects Molluscs Other animal groups

(d) Insects Molluscs Crustaceans Other animal groups

Answer: (d)

5. Which of the following represent maximum number of species among global biodiversity?

(a) Fungi (b) Mosses and Ferns

Answer: (a)

6. Which of the following has maximum genetic diversity in India?

(a) Mango (b) Wheat (c) Groundnut (d) Rice

Answer: . (d) : Genetic diversity is the diversity in the numbers and types of genes as well as chromosomes present in different species and the variations in the genes and their alleles in the same species. Oryza sativa (rice) has 32,000-50,000 genes.

7. Choose the right one which denotes genetic diversity.

(a) Chromosomes → Nucleotides → Genes → Individuals → Populations

(b) Populations → Individuals → Chromosomes → Nucleotides → Genes

(d) Nucleotides → Genes → Chromosomes → Individuals → Populations

Answer: (d)

8. Biodiversity of a geographical region represents

(a) endangered species found in the region

(b) the diversity in the organisms living in that region

(d) species endemic to the region.

Answer: (b)

9. The species diversity of plants on earth will be

(a) 2.4% (b) 22%

Answer: (b) : The number of known species in India is 1,42000 or roughly 8.1 % of the total though India has only 2.4% land area. The most interesting aspect of biodiversity is that more than 70% of all species are animals while plants account for only 22%.

10. Alexander von Humboldt described for the first time

(a) laws of limiting factor

(b) species area relationships

(d) ecological biodiversity

Answer: (b) : Alexander von Humboldt described species area relationship for the first time. He observed that within a region, species richness increases with increasing explored area, but only upto a limit.

11. Identify the ecologist from the given hints.

(i) He carried out long-term ecosystem experiments using outdoor plots.

(ii) In his experiments he showed that “increased diversity contributed to higher productivity”.

(a) Ahmed Khan (b) David Tilman

Answer: (b)

12. Species area relationship curve had been proposed by

(a) David Tilman (b) Edward Wilson (c) Paul Ehrlich (d) von Humboldt.

Answer: (d) : German naturalist and geographer Alexander von Humboldt while exploring the wilderness of South American jungles found that within a region the species richness increased with increasing area but upto a certain limit. On this basis, he proposed species area relationship curve. The relationship between species richness and area turned out to be rectangular hyperbola for a wide variety of taxa whether they are birds, bats, freshwater fish or flowering plants. On a logarithmic scale, it is a straight line. It is described by the equation: log S = log C + Z log A

13. The relation between species richness and area is described on a logarithmic scale by the equation_____ [where S = species richness, A = area, Z = slope of the line (regression coefficient), C= Y-intercept].

(a) log S = log C – Z log A

(b) log S = Z log A

(d) log S = log C

Answer: (c) : German naturalist and geographer Alexander von Humboldt while exploring the wilderness of South American jungles found that within a region the species richness increased with increasing area but upto a certain limit. On this basis, he proposed species area relationship curve. The relationship between species richness and area turned out to be rectangular hyperbola for a wide variety of taxa whether they are birds, bats, freshwater fish or flowering plants. On a logarithmic scale, it is a straight line. It is described by the equation: log S = log C + Z log A

14. Which of the following is the most important for animals and plants being driven to extinction?

(a) Alien species invasion

(b) Habitat loss and fragmentation

(d) Economic exploitation

Answer: (b) : Habitat loss and fragmentation is the most important cause driving animals and plants to extinction. When large habitats are broken into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habitats are badly affected, leading to population declines. The same can be applicable to the plant (forest) loss and degradation as millions of species are being cut and cleared for the expansion of agricultural land, harvesting timber, as well as overgrazing.

15. Decline in the population of indian native fishes due to introduction of Clarias gariepinus in river Yamuna can be categorised as

(a) co-extinction

(b) habitat fragmentation

(d) alien species invasion.

Answer: (d)

16. Which of the following is correctly matched?

(a) Aerenchyma – Opuntia

(b) Age pyramid – Biome

biodiversity

(d) Stratification – Population

Answer: (c) : Parthenium hysterophorus is commonly known as congress grass or carrot weed. It is herbaceous annual plant of Family Asteraceae. It is a deadly invasive, noxious weed infesting cropped and non-cropped areas. It rapidly colonises area replacing the native vegetation and causes a number of human health related problems such as skin allergy, rhinitis and eye irritations. Also, being toxic and unpalatable it causes fodder scarcity. Hence, it is considered a threat to the biodiversity.

17. Red list contains data or information of

(a) all economically important plants

(b) plants whose products are in international trade

(d) marine vertebrates only.

Answer: (c) : A red data book or red list is a catalogue of taxa facing risk of extinction. Red data book or red list was initiated in 1963.

18. Read the statements regarding a stable community and choose the correct option.

(i) Must be resistant to occasional disturbances.

(ii) Should show much variation in productivity from year to year.

(iii) Must be resistant to invasions by alien species.

(a) (i) and (ii) are correct.

(b) (i), (ii) and (iii) are correct.

(d) (i) and (iii) are correct.

Answer: (d) : Climax community is the stable, self perpetuating and final biotic community that develops at the end of biotic succession and is in perfect harmony with the physical environment. Climax community has maximum diversity and niche specialization. It should not show too much variation in productivity from year to year.

19. With respect to Eichhornia: Statement X : It drains off oxygen from water and is seen growing in standing water. Statement Y : It is an indigenous species of our country.

(a) Only statement X is correct and Y is wrong. (b) Both statements X and Y are correct.

Answer: (a) : Eichhornia is an alien or exotic species. This plant was introduced in India because of its beautiful flowers and shape of leaves. It can propagate vegetatively at a phenomenal rate and spread all over the water body in a short period of time. It drains off oxygen from water, which leads to death of fishes. It is also known as “Terror of Bengal”.

20. A species facing extremely high risk of extinction in the immediate future is called

(a) vulnerable (b) endemic

Answer: (c) : The taxon under critically endangered category are facing very high risk of extinction in the wild and can become extinct at any moment in the immediate future.

21. The organisation which publishes the Red

list of species is

(a) ICFRE (b) IUCN

Answer: (b) : IUCN is International Union of Conservation of Nature and Natural Resources which is now called World Conservation Union (WCU). It has its headquarters at Morges, Switzerland. It maintains a red data book or red list which is a catalogue of taxa facing risk of extinction. Red data book or red list was initiated in 1963. The Red list of year 2000 has made assessment of 18,000 species.

22. In IUCN Red List (2004) documents the extinction of 784 species includes

(a) 335 vertebrates, 360 invertebrates and 89 plants

(b) 337 vertebrates, 362 invertebrates and 88 plants

(d) 340 vertebrates, 357 invertebrates and 87 plants.

Answer: (c)

23. One of the chief reasons among the following for the depletion in the number of species making it endangered is

(a) over-hunting and poaching

(b) greenhouse effect

(d) habitat destruction.

Answer: (d) : Destruction of natural habitats causes the most serious threat to the biodiversity, endangering many animals. Habitats are destroyed/fragmented by many human activities like developmental work, deforestation, pollution, etc. Over hunting and poaching also have harmful effect.

24. Select the incorrect statement.

(a) Species diversity increases as we move away from the equator towards the poles.

(b) Stellar’s sea cow and passenger pigeon got extinct due to over exploitation by man.

(d) The historic convention on biological diversity was held in 1992.

Answer: (a) : Species diversity on earth is not uniformly distributed but shows interesting patterns. It is generally highest in the tropics and decreases towards the poles. Important explanations for the species richness of the tropics are: tropics had more evolutionary time they provide a relatively constant environment and they receive more solar energy which contributes to greater productivity.

26. The alien species introduced into Lake Victoria that was responsible for the extinction of Cichlid fishes is

(a) African catfish (b) water hyacinth (c) carrot grass (d) Nile perch

Answer: (d) : Nile Perch (a predator fish) was introduced in lake Victoria of Africa. It killed and eliminated ecologically unique assemblage of over 200 native species of small Cichlid fish.

27. The Earth Summit held in Rio de Janeiro in 1992 was called

(a) for immediate steps to discontinue use of CFCs that were damaging the ozone layer

(b) to reduce CO2 emissions and global warming

(d) to assess threat posed to native species by invasive weed species.

Answer: (c) : ‘The Earth Summit’ held in Rio de Janeiro in 1992, called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilisation of its benefits.

30. All of the following are included in ‘ex-situ conservation’ except

(a) wildlife safari parks (b) sacred groves (c) botanical gardens (d) seed banks.

Answer: (b) : Sacred groved come under in situ conservation and represent the pristine forest patches around places of worship which are held in high esteem by tribal communities. Cutting of trees and branches is prohibited due to religious reasons. Wildlife safari parks, botanical gardens and seed banks come under ex-situ conservation.

31. Which one of the following is related to ex-situ conservation of threatened animal and plants?

(a) Biodiversity hotspots

(b) Amazon rainforest

(d) Wildlife safari parks

Answer: (d) : Ex-situ conservation is conservation of selected rare or threatened animals and plants in places outside their natural homes. It includes offsite collections like botanical gardens, zoological parks, cryopreservation, tissue culture, wildlife safari parks and gene banks, etc.

32. The region of biosphere reserve which is legally protected and where no human activity is allowed is known as

(a) buffer zone ( b) transition zone (c) restoration zone (d) core zone.

Answer: (b)

33. How many hotspots of biodiversity in the world have been identified till date by Norman Myers?

(a) 17 (b) 25

Answer: (c) : Biodiversity hotspots are a method to identify those regions of the world where attention is needed to address biodiversity loss and to guide investments in conservation. The idea was first developed by Norman Myers in 1988 to identify tropical forests hotspots characterised both by exceptional levels of plant endemism and serious habitat loss which he then expanded to a more global scope. Currently, 34 biodiversity hotspots have been identified most of which occur in tropical forests.

34. Which of the following National Parks is home to the famous musk deer or hangul?

(a) Keibul Lamjao National Park, Manipur

(b) Bandhavgarh National Park, Madhya Pradesh

(d) Dachigam National Park, Jammu and Kashmir

Answer: (d)

35. World summit on sustainable development was held in

Answer: (c) : The World Summit on sustainable development was held in 2002 in Johannesburg, South Africa.

36. One of the following statements is incorrect with reference to biodiversity. Identify it.

(a) The areas with very few plant and animal species (low species richness) with no threatened species are called biodiversity hotspots.

(b) Biodiversity increases from higher altitudes to lower altitudes.

(d) Depletion in genetic diversity of crop plants is mainly due to the introduction of better varieties with high yield, disease resistance, etc.

Answer: (a) : Biodiversity hotspots are areas of high endemism and high level of species richness. They are determined mainly by three factors:

(i) Number of species/species diversity

(ii) Degree of endemism

(iii) Degree of threat

37. Which one of the following is not an in situ conservation method?

(a) National parks (b) Wild life sanctuary (c) Biosphere reserves (d) Zoological parks

Answer: (d) : Zoological parks, wildlife safari parks, botanical gardens, etc., are ex situ form of conservation of biodiversity.

38. Find the wrongly matched pair.

(a) Endangered species – Species confined to a region and not found anywhere else

(b) Hotspots – Western Ghats

(d) Ex situ conservation – Zoological parks

Answer: (a) : An endangered species is one which is liable to become extinct if not allowed to realise its full botic potential by providing protection from exotic species/human exploitation/habitat deterioration/depletion of food.

39. Which of the following is not an ex-situ conservation?

(a) Cryopreservation (b) Seed bank (c) Biosphere reserves (d) Botanical garden

Answer: (c)

40. Conservation of organisms in natural

habitat is called

(a) ex situ conservation

(b) in situ conservation

(d) none of these.

Answer: (b)

Case Based MCQs

Case I : Read the following passage and answer the questions from 41 to 45 given below.

Within a region, species richness increases with increasing explored area, but only upto a limit. The given graph explains this relationship.

41. What does the given figure show?

(a) Rivet-popper hypothesis

(b) Species-area relationship

(d) a-ecological diversity

Answer: (b)

42. Equation for relationship (A) between species richness and area is

(a) log S = log C + Z log A

(b) log C = log S + Z log A

(d) log S = log C + log A.

Answer: (a) : On a logarithmic scale, the relationship between species richness and area is a straight line. It is described by the equation log S = log C + z log A

43. What is the value of slope of line or regression coefficient Z for frugivorous birds?

(a) 0.1-0.2 (b) 1.15 (c) 0.01-0.1 (d) 0.6-1.2

Answer: (b) : The regression coefficient Z have a value of 1.15 for frugivorous birds and mammals of tropical forests of different continents.

44. The shape of curve for relationship between species richness and areas for a wide variety of taxa is

(a) straight line

(b) parabola

(d) bell shaped.

Answer: (c)

45. Who gave this concept of increase in species richness with increasing area?

(a) Humboldt (b) Odum

Answer: (a) : While exploring the wilderness of South American jungles, Alexander von Humboldt found that within a region, the species richness increased with increasing area but upto a certain limit.

Case II : Read the following passage and answer the questions from 46 to 50 given below.

Biosphere reserves are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional life style of tribals and domesticated plant/animal genetic resources. Each biosphere reserve has three zones-core, buffer and transition zone.

46. Which of the following is similar to biosphere reserve in terms of conservation?

(a) Gene banks

(b) Offsite collection

(d) Hotspots

Answer: (d) : Biosphere reserves and hotspots are in-situ methods of conservation

47. Refer to the given figure representing different zones of a biosphere reserve and select the correct option regarding it.

(a) A-Limited human activity is allowed such as for research and education.

(b) B-An active co-operation occurs between reserve management and local people for activities like cropping, settlements, etc.

(d) None of these

Answer: (d)

48. Refer to the given diagrammatic representation of a biosphere reserve.

Select the incorrect statement regarding X, Y and Z.

(i) X is devoted to strict protection of wildlife and no human activity is allowed in this zone.

(ii) In Y, only limited human activity (compatible with conservation) is allowed.

(iii) In X, commercial exploitation of natural resources is allowed.

(iv) Tourism is allowed in Y zone only.

(v) Zone Y helps to maintain the lifestyle of the tribal people living in the area.

(a) (iii), (iv) and (v) only

(b) (ii), (iii) and (v) only

(d) (ii), (iii) and (iv) only

Answer: (a) : In the given figure, X, Y and Z represent core zone, buffer zone and transition zone of biosphere reserve, respectively. No commercial exploitation of natural resources is allowed in core zone. Tourism is allowed in transition zone of biosphere reserve. Transition zone helps to maintain the lifestyle of the tribal people living in the area.

49. Biosphere reserves differ from national parks and wildlife sanctuaries because in the former

(a) human beings are not allowed to enter

(b) people are an integral part of the system

(d) living organisms are brought from all over the world and preserved for posterity.

Answer: (b) : Biosphere reserves have a transition zone where participation of local people for activities like settlements, cropping, recreation, forestry, etc. take place.

50. MAB Programme means

(a) Man and biosphere programme

(b) Man and biodiversity conservation programme

(d) none of these.

Answer: (a)

Short Answer Type Questions (SA-I)

1. What is an exotic species?

Answer: New species entering a geographical region are called exotic species.

2. About 200 species of cichlid fish became extinct when a particular fish was introduced in lake Victoria of Africa. Name the invasive fish

Answer: Nile perch

3. Name any three sites of sacred groves.

Answer : (i) Khasi and Jaintia hills in Meghalaya.

(ii) Aravall Hills of Rajasthan

(iii) Sarguja, Chanda and Bastar areas of Madhya Pradesh

4. Eichhornia crassipes is an alien hydrophyte introduced in India. Mention the problems posed by this plant.

Answer: Eichhornia crassipes, an alien hydrophyte was introduced in Indian waters due to aesthetic value but it turned out to be a problematic species. It has clogged water bodies resulting in death of aquatic plants and animals.

5. India has more than 50,000 strains of rice. Mention the level of biodiversity it represents.

Answer: When species show high diversity at the genetic level over its distributional range then the biodiversity is at genetic diversity level. The 50,000 strains of rice differ at genetic level.

6. Who proposed Rivet popper hypothesis?

Answer: The Rivet popper hypothesis was proposed by Stanford ecologist Paul Ehrlich7.

7. Name the type of biodiversity represented by the following:
(a) 1000 varieties of mangoes in India.
(b) Variations in terms of potency and concentration of reserpine in Rauwolfia vomitoria

growing in different regions of Himalayas

Answer: (a) Genetic diversity (b) Genetic diversity

8. Name the three zones of biosphere reserves.

Answer: Biosphere reserves have three zones:

Core or natural zone: Undisturbed and legally protected area where no human activity is allowed.

Buffer zone: Limited human activity like research, education and resource utilisation strategies are allowed. Transition zone: Outermost region where human activity like recreation, cropping, forestry, etc., are allowed.

9. Mention one application of pollen bank. How are pollens stored in a bank?

Answer: Pollen banks are used to maintain stocks of biodiversity. Pollens are stored in a bank at a very low temperature of –196°C in liquid nitrogen, i.e., by cryopreservation.

10. Sometimes introduction of an exotic species upsets native species of the ecosystem.
Substantiate the statement with two examples from India.

Answer: Exotic species often become invasive and drive away the local species. Water hyacinth was introduced in Indian waters due to its aesthetic value. However, it has clogged water bodies resulting in death of several aquatic plants and animals. Eupatorium odoratum has reduced the population of Tectona grandis in North-East.

11. (a) “India has greater ecosystem diversity than Norway”. Do you agree with the statement? Give reasons in support of your answer.

(b) Write the difference between genetic biodiversity and species biodiversity that exists
at all the levels of biological organisation.

Answer (a) Yes, India has a greater ecosystem diversity than Norway as India comes under the tropical region whereas, Norway lies in temperate region. Tropical regions account for greater biological diversity as they have deserts, rainforests, mangroves, coral reefs, wetlands, estuaries and alpine meadows than temperate regions. In tropical region, more solar energy is available that also promotes higher productivity and increased biological diversity.

(b) Differences between genetic and species biodiversity are as follows :

12. What is IUCN red list? Give any two uses of this list.

Answer: IUCN red list is a catalogue of taxa facing risk of extinction. The two uses of this list are:

(i) It provides awareness to the degree of threat to biodiversity.

(ii) It is useful in identification and documentation of species which are at high risk of extinction.

13. Differentiate between in situ and ex situ approaches of conserving biodiversity.

Answer: Differences between in situ and ex situ conservation are:

14. What is beta diversity in an ecosystem? What is the significance of large genetic diversity in a population ?

Answer: Beta diversity is diversity which develops due to change in habitat or community along environmental gradients like altitude, latitude, moisture gradient, etc. Higher beta diversity indicates the presence of unique habitats or unique communities in the region.

Genetic diversity enables a population to adapt to its environment and the changes occurring in the environment. Genetic diversity within a species is the basis of speciation or formation of new species.

15. What is alpha diversity in an ecosystem?

Answer: Alpha diversity is diversity present in organisms sharing the same community present in an area of more or less uniform habitat. Alpha diversity determines the stability of the community, as more diversity indicates better adjustment and interrelationships amongst the members of the community.
16. Where would you expect more species biodiversity– in tropics or in polar regions? Give reasons in support of your answer.

Answer: Tropics have more species biodiversity than the polar regions because of favourable environmental conditions as compared to polar regions where harsh conditions are prevalent. The reasons behind the maximum biological diversity of tropical regions are:

(i) Prolonged evolutionary time : Speciation is generally a function of time, unlike polar regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.

(ii) High productivity : There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity.

17. Giving two reasons explain why there is more species biodiversity in tropical latitudes
than in temperate ones.

Answer: The two reasons for more species biodiversity in tropical latitudes than in temperate ones are:

(i) Temperate region was subjected to frequent glaciations in the past, while tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.

(ii) Tropical environments, unlike temperate ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialisation and lead to a greater species diversity.

18. Mention the kind of biodiversity more than a thousand varieties of mangoes in India
represent. How is it possible?

Answer: “More than a thousand varieties of mango in India” exhibit genetic diversity. Genetic diversity represents the diversity in number and types of genes as well as chromosomes present in different species and variations in the genes and their alleles in the same species.

The reason for this genetic diversity is the occurrence of variations in environmental parameters and use of horticulture techniques like grafting, breeding, etc.

19. Why are sacred groves highly protected?

Answer: Sacred groves are forest patches around places of worship, held in high esteem by tribal communities. They are most undisturbed forest patches which are often surrounded by highly degraded landscapes. Not a single branch is allowed to be cut from these forests and as a result, many endemic species which are rare or have become extinct elsewhere can be seen to flourish here. E.g., Jaintia and Khasi hills in Meghalaya.

20. Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species.

Answer: Extinction of species due to human activities is known as anthropogenic extinction. Various human activities have led to extinction of particular species. The most common example is Nile perch, a large predator fish introduced in Lake Victoria for commercial purpose turned out to be a problematic species. It started feeding on the native fish cichlid fish, which results in extinction of ecologically unique assemblage of over 200 native species of small cichlid fish.

Short Answer Type Questions (SA-II)

23. Study the given figure and answer the following questions

(a) Identify the figure and the types of diversity labelled as A, B and C in it.

(b) Give a brief description of diversity labelled as A and C.

(c) Which of the diversities labelled as A, B and C will face maximum competition, adjustments and interrelationships amongst the members of the same community?

Answer: (a) The given figure is of ecological diversity. Here, A is alpha diversity, B is beta diversity and C is gamma diversity.

(b) Alpha diversity (A) is a species diversity in a given community or habitat. Alpha diversity is dependent upon species richness and evenness/equitability. Gamma diversity (C) is a diversity present in ranges of communities as represented by diversity of habitats/ecosystems over a total landscape or geographical area.

(c) Alpha diversity (A) will face maximum competition, adjustments and interrelationships amongst the members of the same community.

24. White Bengal tigers are protected in special settings in zoological parks. Tiger reserves are maintained in Western Ghat.

(a) How do these two approaches differ from each other? Mention the advantages of each one.

(b) What is the significance of cryopreservation technique?

Answer: (a) In zoological parks, white Bengal tigers are protected outside their natural habitats. It is a mode of ex situ conservation. Animals are kept under human supervision and are protected against all adverse factors.

Western ghats are hot-spots, i.e., areas of high endemism and high level of species richness. It is a mode of in situ conservation. Endangered species in Tiger reserves are conserved in their natural habitat. These are protected from predators.

(b) Cryopreservation is ex situ conservation technique in which tissues, organs, embryos, seeds, etc., are stored at very low temperature of –196°C. At this temperature the living material can be stored indefinitely in compact, low maintenance refrigeration units. It can be revived as and when required.

25. The following graph shows the species-area relationship. Answer the following question as directed.

(a) Name the naturalist who studied the kind of relationship shown in the graph. Write the observation made by him.

(b) Write the situation as discovered by the ecologists when the value of ‘Z’ (slope of the line) lies between

(i) 0.1 and 0.2 (ii) 0.6 and 1.2

What does ‘Z’ stand for?

Answer: (a) Alexander von Humboldt studied species-area relationship. He observed that within a region, the species richness increased with increasing area but upto a certain limit.

(b) (i) Ecologists have discovered that the value of Z lies in the range of 0.1–0.2 regardless of taxonomic group or region, i.e., whether it is plants in Britain, birds in California or molluscs in New York, the slopes of the regression line are similar.

(ii) When the species-area relationship is considered for a very large area like a whole continent, regression coefficient Z or slope of the line become steeper with Z values in the range of 0.6 –1.2.

(c) Slope of line b, would become steeper when the value of Z ranges from 0.6 to 1.2 as for mammals of tropical forests of different continents, the slope is found to be 1.15.

26. Since the origin of life on Earth, there were five episodes of mass extinction of species.

(a) How is the ‘Sixth Extinction’, presently in progress, different from the previous episodes?

(b) Who is mainly responsible for the ‘Sixth Extinction’?

Answer: (a) Sixth extinction, i.e., the current species extinction is 100 – 1000 times faster than extinctions in pre-human times.

(b) Human activities like settlements, hunting, overexploitation and habitat destruction are mainly responsible for ‘Sixth extinction’.

(i) Planting large number of trees on road sides and where space is available.

(ii) Avoid introduction of invasive alien species.

(iii) Conserving biodiversity by maintaining national parks, zoos, etc.

(iv) Deforestation and fragmentation of forested areas should be stopped.

27. Alien species are highly invasive and are a threat to indigenous species. Substantiate this statement with any three examples.

Answer: Non-native or alien species are often introduced inadvertently by man for their economic and other uses. They often become invasive and drive away the local species. For example:

(i) Water hyacinth (Eichhornia crassipes) was introduced in Indian waters due to its aesthetic value but it turned out to be a problematic species. It has clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.

(ii) Nile Perch (a predator fish) was introduced in lake Victoria of East Africa. It killed and eliminated ecologically unique assemblage of over 200 native species of small cichlid fish.

(iii) African catfish (Clarias gariepinus) introduced for aquaculture in India possess threat to indigenous catfishes.

28. (a) Explain the concept of endemism.

(b) Name four regions in an around our country that are considered hotspots.

Answer: (a) Endemism is the ecological state of a species being unique to a defined geographical location such as an island, nation, country or other defined zone. E.g., The Tasmanian Devil is the largest carnivorous marsupial in the world and found only on the Australian island state of Tasmania.

(b) Western Ghats and Sri Lanka, Indo-Burma and Himalayas are hotspots in India. Others include mountains of southwest China, Caribbean Island hotspot, etc.

29. Name and describe any three causes of biodiversity losses.

Answer: The three major causes of biodiversity loss are :

(i) Habitat loss and fragmentation - Over-population, urbanisation and industrialisation require additional land every year. It can come through destruction or fragmentation of natural habitats through filling wetlands, ploughing grasslands, cutting down trees, burning a forest and clearing some area of vegetation. Loss of habitat results in annihilation of species of endemic plants, microorganisms and forcing out of animals which in alien lands die out after some time. Migrating animals would go astray and get killed.

(ii) Over-exploitation – Excessive exploitation of a species, whether a plant or an animal, reduces size of its population so, that it becomes vulnerable to extinction. Due to overexploitation by humans, Dodo, three subspecies of tiger and Steller’s sea cow have become extinct in the last 500 years.

(iii) Alien species invasions – Non-native or alien species are often introduced by man for their economic and other uses. They often become invasive and drive away the local species.

For example, water hyacinth (Eichhornia crassipes) was introduced in Indian waters due to its aesthetic value but turned out to be a problematic species. It clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.

30. The sacred groves of Aravalli Hills and Ooty botanical garden both aim at biodiversity conservation. How do they differ in their approaches? Explain.

Answer: Sacred groves are undisturbed forest patches, surrounded by highly degraded landscapes where not even a single branch of tree is allowed to be cut. As a result, many endemic species which are rare or have become extinct, seen to flourish here. While botanical gardens are areas where many species of plants, are conserved outside their natural habitats. They help to restore endangered species, whose chances of survival are very small. Thus, sacred groves of Aravalli Hills are sites of in-situ conservation, where endangered species are protected in their natural habitat whereas Ooty Botanical gardens are sites of ex-situ conservation, where the endangered species are protected outside their natural habitats.

31. List any four techniques where the principle of ex situ conservation of biodiversity has been employed.

Answer: Four techniques where principles for ex situ biodiversity conservation has been employed are:

(i) Orchards – Plants with recalcitrant seeds are grown in orchards where all possible strains and varieties are maintained, e.g., litchi.

(ii) Cryopreservation – Cells, embryos, tissues are preserved at – 196°C.

(iii) Seed banks – Storing viable seeds at low temperature, and germinating them to obtain fresh seeds. (iv) Tissue culture – Production of large number of plants through callus culture, pollen grain culture, embryoids, etc.

32. Observe the global biodiversity distribution of major plant taxa in the above diagram and answer the questions that follow.

(a) Which group of plant are most endangered?

(b) Why are mosses/ferns so few? Give reason.

(d) Which group of plant is most advanced and which one is most primitive?

Answer: (a) As per the given pie chart lichens are least in number, also lichens are pollution sensitive so with increasing globalisation we can assume that in near feature lichens will be subject to extinction and hence may be considered as most endangered among the given taxas.

(b) Mosses and ferns grow in shady and humid places or wet places and need water for fertilisation. Hence, they are few in numbers.

(c) Fungi can live as saprotrophs or parasites. As saprotrophs, they depend on only organic matter and hence survive in any environment. They produce a number of thick walled spores, which can withstand the unfavourable conditions and germinate when conditions become favourable. This helps fungi in sustaining a large population.

(d) Angiosperms are the most advanced whereas fungi are the most primitive.

33. ‘In-situ’ conservation can help endangered/threatened species. Justify the statement.

Answer: ‘In-situ’ conservation helps endangered and threatened species by protecting them in their natural habitats along with their ecosystem and its biodiversity. For example, National parks are the areas maintained by the government for better conservation of wildlife. It is a place where cultivation, grazing, forestry and habitat manipulation are restricted. Sanctuaries are places where wild animals can take refuge without being hunted. Activities like collection of forest products, private ownership land, tilling of land, etc., are allowed but animal hunting is prohibited. Biosphere reserves are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional life style of tribals and domesticated plant/animal genetic resources.

34. 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?

Answer: Conservation of biodiversity is protection, uplift and scientific management of biodiversity so as to maintain it at its optimum level and derive sustainable benefits for the present as well as future generations. There are two types of conservation strategies – in situ (on site) and ex situ (offsite). In situ conservation is conservation and protection of the whole ecosystem and its biodiversity at all levels in their natural habitat in order to protect the threatened species. It involves hotspots and protected areas. Hotspots are areas of high endemism and high level of species richness. Protected areas are ecological/biogeographical areas where biological diversity along with natural and cultural resources is protected, maintained and managed through legal or other effective measures. Protected areas include national parks, sanctuaries and biosphere reserves.

Ex situ conservation is conservation of threatened plants and animals in places outside their natural homes under full protection and supervision. It includes offsite collections and gene banks.

Long Answer Type Questions (LA)

35. (a) Explain the species-area relationship using the graphical representation given below.

(b) Explain giving reasons why there is greater biodiversity in tropical regions of the Earth.

Answer:(a) Alexander von Humboldt studied species-area relationship. He observed that within a region, the species richness increased with increasing area but upto a certain limit.

Ecologists have discovered that the value of Z lies in the range of 0.1–0.2 regardless of taxonomic group or region, i.e., whether it is plants in Britain, birds in California or molluscs in New York, the slopes of the regression line are similar.

When the species-area relationship is considered for a very large area like a whole continent, regression coefficient Z or slope of the line become steeper with Z values in the range of 0.6 –1.2.

Slope of line would become steeper when the value of Z ranges from 0.6 to 1.2 as for mammals of tropical forests of different continents, the slope is found to be 1.15.

The equation of curve is S = CAz where,

S = Species richness

C = Y – intercept

A = Area

Z = Slope of the line (regression coefficient).

The graph on species- area relationship shows that within a region, species richness increases with increasing explorable area, but only upto a certain limit. The relation between species richness and area for a wide variety of taxa turns out to be rectangular hyperbola.

(b) Tropics have more species biodiversity than the polar regions because of favourable environmental conditions as compared to polar regions where harsh conditions are prevalent. The reasons behind the maximum biological diversity of tropical regions are:

(ii) High productivity : There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity.

The two reasons for more species biodiversity in tropical latitudes than in temperate ones are:

36. Explain the narrowly utilitarian, broadly utilitarian and ethical arguments in favour of conservation of biodiversity.

Answer: I. There are a number of reasons to conserve biodiversity which can be grouped as:

(a) Narrowly Utilitarian : Human derive a major part of their requirement from organisms. Their direct benefits are countless, like (i) Food : Pulses, fruits, vegetables, milk, egg, meat comes from plants and animals (ii) Fats and oils are obtained from plants and animals. (iii) Firewood as a source of energy for cooking and heating. (iv) Fibres, e.g., cotton, flax, silk, wool. (v) Industrial products like tannins, lubricant,dyes, resins, and perfumes. (vi) Drugs: Nearly 25% of drugs being used by us are directly coming from plants.

(b) Broadly Utilitarian : Biodiversity is fundamental to ecosystem services of nature. For example (i) Oxygen: Through their photosynthetic activity plants are replenishing oxygen of the atmosphere. Amazon rain forest is estimated to contribute 20% of it. (ii) Pollination: Bees, bumble bees, butterflies, moths, beetles, birds and bats are engaged in pollination of plants which is essential for formation of fruits and seeds. (iii) Climate regulation: Forest and oceanic systems regulate global climate. (iv) Aquifers: Plant cover is essential for retention of rain water, its percolation and storage in aquifers and reservoirs. (v) Flood and erosion control: Plant cover protects the soil from wind and water erosion. Run off of rain water is reduced so that flood water is rarely formed. (vi) Nutrient cycling : It is essential for continued availability of nutrients to plants without which there would be no photosynthetic activity.

Ethical Human beings share the biosphere with over a million species of plants, animals and microbes. They have evolved just as we have evolved. Every living species has an intrinsic value though it may not have any direct economic value. It is therefore, our moral and ethical duty not to destroy them. Instead we should take care of their well being so as to pass the rich biological legacy to future generations.

37. (a) Why should we conserve biodiversity? How can we do it?

(b) Explain the importance of biodiversity hotspots and sacred groves.

Answer: (a) Conservation of biodiversity is the protection, uplift and scientific management of biodiversity so as to maintain it at its optimum level and derive sustainable benefits for the present as well as future strategies. The maintenance of a high level of biodiversity is important for the stability of ecosystem. The main reasons to conserve the biological diversity can be grouped in three categories :

– Narrowly utilitarian (useful products for humans like food, fibres, drugs and medicines etc.)

– Broadly utilitarian (ecosystem services like provision of pollination, climate regulation, flood and erosion control, ecological balance through nutrient cycling, microbial waste treatment, biological pest control, aesthetic and cultural values).

– Ethical (every living species has an intrinsic value though it may not have any direct economic value, and also, every species has the right to live).

The two types of conservation strategies are in situ (on site) and ex situ (off site).

In situ conservation is conservation and protection of the whole ecosystem and its biodiversity at all levels in their natural habitat in order to protect the threatened species. It involves hotspots and protected areas. Hotspots are areas of high endemism and high level of species richness. Protected areas are ecological/biogeographical areas where biological diversity along with natural and cultural resources is protected, maintained and managed through legal or other effective measures. Protected areas include national parks, sanctuaries and biosphere reserves.

Ex situ conservation is conservation of threatened plants and animals in places outside their natural homes under full protection and supervision. It includes offsite collections and gene banks.

(b) ‘Biodiversity hotspots’ are the regions which are characterised by very high levels of species richness and high degree of endemism. India has three hotspots – Indo-Burma (North-East India), Himalayas, and Western Ghats. Importance of hotspots are as follows:

– Maintaining genetic diversity of all present species and varieties.

– Maintaining viable populations of native species, subspecies and varieties.

– Maintaining resilience in species/habitats/ecosystems to adapt to environmental changes.

– Maintaining the various types of communities/ ecosystems/habitats both in number and distribution.

– Checking human aided introduction of alien/exotic species.

Sacred forests or sacred groves are forest patches around places of worship which are held in high esteem by tribal communities. They are the most undisturbed forest patches (island of pristine forests) which are often surrounded by highly degraded landscapes. They are found in several parts of India, e.g., Karnataka, Maharashtra, Rajasthan (Aravalli), Chandigarh (Sarguja, Chanada and Bastar), Kerala, Meghalaya. Temples built by tribals are found surrounded by deodar forests in Kumaon region. In Meghalaya scared groves are found in Jaintia and Khasi hills. Not a single branch is allowed to be cut from these forests. As a result, many endemic species which are rare or have become extinct elsewhere can be seen to flourish here. Bishnois of Rajasthan protect Prosopis cineraria and Black Buck religiously. Some water bodies are also held sacred in certain places, e.g., Khecheopalri in Sikkim. Their aquatic flora and fauna are naturally preserved.

38. (a) According to ecologists, tropical regions in the world account for greater biological

diversity. Justify.

(b) Why are habitat loss and alien species invasion considered as the causes of biodiversity loss? Explain with the help of an example of each.

Answer: (a) On the land, maximum primary productivity is found in tropical rainforest. Various factors which contribute to high productivity in tropics are discussed ahead. Maximum light is available in tropics. Due to this photosynthesis is maximum and net primary productivity is highest in tropics. Climate of tropics is warm and humid. Appropriate temperature, rain and humidity increase productivity of tropics. Moreover, ecosystem with higher biodiversity are more productive. (b) Loss of habitat results in annihilation of plants, microorganisms and forcing out of animals which in alien lands die out after sometime due to unfavourable conditions. Fragmentation of habitats results in disruption of complex interactions among species and animals requiring large territories are badly affected. E.g., mammals and birds.

Alien species often become invasive and drive away the local species. They have proved harmful in both aquatic and terrestrial ecosystems. E.g., water hyacinth was introduced in Indian waters to reduce pollution. It clogged water bodies at many places resulting in death of several plants and animals.

Saturday, 5 March 2022

Biodiversity and conservation important questions

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