CHAPTER 15: BIODIVERSITY AND CONSERVATION

INTRODUCTION

1. There are more than ____ species of ants, ____ species of beetles,

_____ species of fishes and nearly ____ species of orchids on earth.

20,000; 3,00,000; 28,000, 20,000

BIODIVERSITY

2. In our biosphere, immense diversity (or heterogeneity) exists not

only at the species level but al all levels of biological organisation

ranging from ____ within cells to ____.

macromolecules, biomes

3. Biodiversity is the term popularised by sociobiologist ____ ____ to

describe the combined diversity at all levels of biological

organisation.

Edward Wilson

4. Some of the important diversity levels are genetic diversity, species

diversity and ecological diversity.

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5. What do you understand by genetic diversity?

(i) A single species might show high diversity at the genetic level

over its distributional range. (Memorise this sentence)

(ii) The genetic variation shown by the medicinal plant ____

____ growing in different Himalayan ranges might be in

terms of ____ and ____ of the active chemical, ____, that the

plant produces.

Rauwolfia vomitoria, potency, concentration reserpine

6. Give examples of genetic diversity in India.

India has more than ____ genetically different strains of rice and

____ varieties of mangoes.

50,000; 1,000

7. Species diversity is at the ____ level. For example, the Western

Ghats have a greater ____ species diversity than the Eastern Ghats.

amphibian

8. Ecological diversity is at the _____ level. For instance, India, with

its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries

and alpine meadows has a greater ecosystem diversity than a

Scandinavian country like Norway.

ecosystem

HOW MANY SPECIES ARE THERE ON THE EARTH AND

HOW MANY IN INDIA?

9. According to IUCN (2004), the total number of plant and animal

species described so far is slightly more than ____ million. But, we

are not clear on how many species are yet to be discovered and

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described.

1.5

10. For many taxonomic groups, species inventories are more complete

in temperate than in tropical countries. Considering that an

overwhelmingly large proportion of the species waiting to be

discovered are in the tropics, biologists make a statistical

comparison of the temperate-tropical species richness of an

exhaustively studied group of ____ and extrapolate this ratio to

other groups of animals and plants to come up with a gross

estimate of the total number of species on earth.

insects

11. A more conservative and scientifically sound estimate made by

____ ____ places the global species diversity at about _____.

Robert May, 7 million

12. More than ____% of all the species recorded are animals while

plants (including algae, fungi, bryophytes, gymnosperms and

angiosperms) comprise no more than ____% of the total.

70, 22

13. Among animals, ____ are the most species-rich taxonomic group,

making up more than ____% of the total animals

insects, 70

14. The number of ____ species in the world is more than the combined

total of the species of fishes, amphibians, reptiles and mammals.

fungi

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15. Look in the figure below for biodiversity of major taxa.

16. It is difficult to ascertain the number of species. Conventional

taxonomic methods are not suitable for identifying microbial

species and many species are cannot be ____ under laboratory

conditions.

cultured

17. India has only 2.4% of the world’s land area. But, its share in the

global species diversity is ____%. This makes India one of the 12

mega diversity countries of the world.

8.1

4

18. Nearly ____ species of plants and twice as many of animals have

been recorded in India.

45,000

19. If we accept May’s global estimate, only 22% of the total species

have been recorded so far.

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PATTERNS OF DIVERSITY

(1) LATITUDINAL GRADIENTS

20. Many groups of animals or plants show a ____ _____ in the

distribution patterns of diversity. In general, species diversity ____

(decreases/increases) as we move from the equator to the poles.

latitudinal gradient, decreases

21. With very few exceptions, the tropics harbour more species than

the temperate or polar areas.

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22. Colombia, located near the equator, has nearly ____ species of

birds while New York at 410 N has ____ species and Greenland at

710 N has only ____ species of birds. India has more than ____

species of birds.

1400, 105, 56, 1200

23. A forest in a tropical region like Ecuador has up to 10 times as

many species of vascular plants as a forest of equal area in a

temperate region like Midwest of the USA.

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24. The Amazon Rain Forests in South America has the greatest

biodiversity on earth. It is home to more than 40,000 species of

plants, 3,000 species of fishes, 1,300 species of birds, 427 species of

mammals, 427 of amphibians, 378 of reptiles and of more than

_____ species of invertebrates. Scientists believe that in these rain

forests, there may be at least 2 million insect species waiting to be

discovered.

1,25,000

25. Why do tropics have a greater biological diversity?

(i) Speciation is generally a function of time. Unlike the temperate

regions, which have been subjected to frequent glaciations in the

past, tropical latitudes have remained relatively undisturbed for

millions of years. Thus, they 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 greater

species diversity

(iii) There is more solar energy available in the tropics, which

contributes to higher productivity. This contributes, indirectly, to

greater diversity.

SPECIES – AREA RELATIONSHIP

26. Alexander von Humboldt, from Germany, observed that within a

region species richness increased with increasing explored ____,

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but only up to a ____.

area, limit

27. The relationship between species richness and area for a wide

variety of taxa turns out to be a rectangular ____. On a logarithmic

scale, the relationship is a ___ ____described by the equation ____.

hyperbola, straight line

log S = log C + Z log A

Where,

S = Species richness

A = Area

Z = Slope of the line (regression coefficient)

C = Y-intercept (should be log C?)

28. Look at the graph below showing species area relationship.

29. Ecologists have discovered that the value of Z lies in the range of

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_____ regardless of the taxonomic group or region. However, when

species-area relationships among very large areas like entire

continents are analysed, the slope of the line is steeper – Z values

range from _____.

0.1 – 0.2, 0.6 – 1.2

30. For Frugivorous (fruit-eating birds) and mammals in the tropical

forests of different continents, the slope (Z) is found to be ____.

1.5

THE IMPORTANCE OF SPECIES DIVERSITY

31. What does one understand by the stability of a community?

A stable community

(i) Should not show too much variation in ____ from year to

year.

(ii) It must either be resistant or resilient to occasional ____

(natural or man-made).

(iii) It must also be resistant to invasion by ____ species.

productivity, disturbances, alien

32. ____ ____ long-term ecosystem experiments using outdoor plots

showed that plots with more species showed ____ (less/more) year-

to-year variation in total biomass. He also showed that increased

diversity contributed to ____ (higher/lower) productivity.

David Tilman’s, less, higher

33. TRUE OR FALSE? Rich diversity is not only essential for

ecosystem health but imperative for the very survival of the human

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race on this planet.

True

34. Read the ‘rivet popper hypothesis’ used by Stanford ecologist Paul

Ehrlich.

LOSS OF BIODIVERSITY

35. The colonisation of tropical Pacific Islands by humans is said to

have led to the extinction of more than ____ species of native birds.

2000

36. The IUCN Red List (2004) documents the extinction of ____ species

in the last 500 years. These include ____ vertebrates, ____

invertebrates and ____ plants.

784, 338, 359, 87

37. Name the animal of Mauritius that has become extinct recently.

Dodo

38. Name the animal of Africa that has become extinct recently.

Quagga

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39. Name the animal of Australia that has become extinct recently.

Thylacine

40. Name the animal of Russia that has become extinct recently.

Stellar’s Sea Cow

41. Name the three species of tiger that has become extinct recently.

Bali, Japan, Caspian

42. The last 20 years alone have witnessed the disappearance of ____

species.

27

43. Data shows that extinctions across taxa are not random. Some

groups like ____ appear to be more vulnerable to extinction.

amphibians

44. More than ____ species, worldwide, are facing the threat of

extinction.

15,500

45. Presently, ____% of all bird species, ____% of all mammal species,

____% of all amphibian species, and ____% of all gymnosperms in

the world face the threat of extinction.

12, 23, 32, 31

46. During the long period (> 3 billion years) since the origin and

diversification of life on earth, there were ____ episodes of mass

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extinction of species.

five

47. The ‘sixth extinction’ presently in progress is different from the

previous episodes in terms of rate. It is 100 – 1000 times faster than

in pre-human times. Human activities are the main culprit for this

extinction. Ecologists warn that if the present trends continue,

nearly ____ of all the species on earth might be wiped out within

the next 100 years.

half

48. What may be the consequences of loss of biodiversity in a region?

(i) Decline in plant production.

(ii) Lowered resistance to environmental perturbations such as

drought.

(iii) Increased variability in certain ecosystem processes such as plant

productivity, water use and pest and disease cycles.

49. There are four main causes of accelerated rates of species

extinctions. These are called ‘____ ____ ____’.

The Evil Quartet

50. There are four main causes of accelerated rates of species

extinctions. What are they?

(i) Habitat loss and fragmentation

(ii) Over exploitation

(iii) Alien species invasions

(iv) Co-extinctions

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HABITAT LOSS AND FRAGMENTATION

51. TRUE OR FALSE? Habitat loss and fragmentation is the most

important cause driving animals to extinction.

True

52. The most dramatic examples of habitat loss come from ____ ____

forests. Once covering more than ____% of the earth’s land

surface, they now cover no more than ____%.

tropical rain, 14, 6

53. The ____ rain forests are called the ‘lungs of the planet’. These

forests are being cleared for cultivating ____ ____ or for conversion

to ____ for raising beef cattle.

Amazon, soybeans, grasslands

54. Besides total loss, the degradation of many habitats by ____ also

threatens the survival of many species.

pollution

55. When large habitats are broken up into small fragments due to

various human activities, mammals and birds requiring large ____

and certain animals with ____ habits are badly affected leading to a

decline in their population.

territories, migratory

OVER-EXPLOITATION

56. Many species have become extinct in the last five years due to over-

exploitation by humans. Examples are ____ ____ ____ and ____

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____.

Stellar’s sea cow, passenger pigeon

57. Presently many marine fish are over harvested endangering the

continued existence of some commercially important species.

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ALIEN SPECIES INVASION

58. When alien species are introduced, either unintentionally or

deliberately, for whatever purpose, some of them turn ____ and

cause decline or extinction of indigenous species.

invasive

59. The ____ _____ introduced into Lake Victoria in east Africa led

eventually to the extinction of an ecologically unique assemblage of

more than 200 species of ____ fish in the lake.

Nile perch, cichlid

60. Some invasive weed species of plant that are a threat to our native

species are ____ ____, ____ and ____ _____.

carrot grass (Parthenium), Lantana, water hyacinth (Eicchornia)

61. The recent illegal introduction of the African catfish, ____ _____,

for aquaculture purposes is posing a threat to the indigenous

catfishes in our rivers.

Clarias gariepinus

CO-EXITINCTIONS

62. When a plant becomes extinct, the plant and animal species

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associated with it in an ____ way also become extinct.

obligatory

63. When a host fish species becomes extinct, its unique assemblage of

____ also meets the same fate.

parasites

64. In the case of a co-evolved plant-pollinator ____, where extinction

of one invariably leads to the extinction of the other.

mutualism

BIODIVERSITY CONSERVATION

65. Arguments for conservation of biodiversity can be broadly grouped

into three categories. Name them.

Narrowly utilitarian, broadly utilitarian and ethical

66. Explain the ‘narrowly utilitarian’ concept for conserving

biodiversity.

(i) Humans derive countless direct economic benefits from nature –

food, medicines, industrial products, etc.

(ii) With increasing resources put into ‘bioprospecting’, nations

endowed with rich biodiversity can expect to reap enormous

benefits.

67. What is bioprospecting?

Bioprospecting includes exploring molecular genetic and species-level

diversity for products of economic importance.

68. More than ____% of the drugs currently sold in the market

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worldwide are derived from plants.

25

69. ____ species of plants contribute to the traditional medicines used

by native people around the world.

25,000

70. Explain the ‘broadly utilitarian’ concept for conserving

biodiversity.

(i) Biodiversity plays a major role in many ecosystem services that

nature provides.

(ii) Such services include provision of oxygen, pollination,

recreation, etc.

(iii) The price for such services is immense and is a reason for

preservation of biodiversity.

71. The Amazon forest is estimated to produce, through

photosynthesis, nearly ____% of the total oxygen in the earth’s

atmosphere.

20

72. Explain the ‘ethical’ concept for conserving biodiversity.

(i) There is an ethical obligation that we owe to plants, animals and

microbe species with whom we share the planet.

(ii) Philosophically or spiritually, we need to realise that every

species has an intrinsic value, even if it is not of any economic

importance to us.

(iii) We have a moral duty of care for their well-being and pass on

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our biological legacy in good order to future generations.

HOW DO WE CONSERVE BIODIVERSITY?

73. What is ‘in situ’ conservation?When we conserve and protect the whole ecosystem, its biodiversity at

all levels is protected. For example, we save the entire forest to save the

tiger. This approach is called ‘in situ’ (on site) conservation.

74. What is ‘ex situ’ conservation?There are situations where an animal or plant is endangered or

threatened and needs urgent measures to save it from extinction. In

such cases ‘ex situ’ is the desirable approach.

IN SITU CONSERVATION

75. What is the difficulty with in situ conservation?(i) Faced with the conflict between development and conservation,

many nations find it unrealistic and economically not feasible to

conserve all their biological wealth.

(ii) Invariably, the number of species waiting to be saved from

extinction far exceeds the conservation resources available.

76. How has the problem of competition between conservation and

development been resolved?

(i) To solve the problem of competition between conservation and

development, ‘biodiversity hotspots’ have been identified for

maximum protection.

(ii) These areas have very high levels of species richness and high

degree of endemism.

(iii) They are also areas of accelerated habitat loss.

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77. What is endemism?

Endemism means that species confined to a region are not found

anywhere else.

78. Initially ____ biodiversity hotspots were identified, which has now

expanded to ____.

25, 34

79. Mention three biodiversity hotspots in India that have been

identified.

(i) Western Ghats and Sri Lanka

(ii) Indo – Burma

(iii) Himalayas

80. All the biodiversity hotspots put together cover less than ____% fo

the earth’s land area, the number of species they collectively

harbour is extremely high. Strict protection of these hotspots could

reduce the ongoing mass extinctions by almost ____%.

2, 30

81. In India, ecologically unique and biodiversity-rich regions are

legally protected as ____ ____, ____ ____ and _____.biosphere reserves, national parks, sanctuaries

82. India now has ____ biosphere reserves, ____ national parks and

____ wildlife sanctuaries.

14, 90, 448

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83. India has a history of religious and cultural traditions that

emphasised the protection of nature. In many cultures, tracts of

forest were set aside and all the trees and wildlife within were

venerated and given total protection. Such sacred groves are found

in ____ and ____ hills in Meghalaya, ____ Hills in Rajasthan, ____

____ regions in Karnataka and Maharashtra and the ____, ____

and ____ areas of Madhya Pradesh.

Khasi, Jaintia, Aravalli, Western Ghats, Sarguja, Chanda, Bastar

84. In _____, the sacred groves are the last refuges for a large number

of rare and threatened plants.

Meghalaya

EX SITU CONSERVATION

85. In the ex situ conservation approach, threatened animals and

plants are taken out from their natural habitats and placed in

special settings where they can be protected and given special care.

____ parks, ____ gardens and wildlife ____ parks serve this

purpose. Zoological, botanical, safari

86. TRUE OR FALSE? There are many animals that have become

extinct in the wild but continue to be maintained in zoological

parks.

True

87. In recent years, ex situ conservation has advanced beyond keeping

threatened species in enclosures. Now, ____ of threatened species

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can be preserved in viable and fertile conditions for long periods

using ____ techniques. Eggs can be fertilised ____ ____ and plants

can be propagated using ____ ____ methods. Seeds of different

genetic strains of commercially important plants can be kept for

long periods in ____ ____.

gametes, cryopreservation, in vitro, tissue culture, seed banks

88. Mention some international efforts in biodiversity conservation.

The Convention on Biological Diversity (‘The ____ Summit’) held

in Rio de Janeiro in ____ called upon all nations to take

appropriate measures for the conservation of ____ and ____

utilisation of its benefits.

Earth, 1992, biodiversity, sustainable

89. In a follow up to the Earth Summit, at the World Summit on

Sustainable Development held in ____ in ____, South Africa, 190

countries pledged their commitment to achieve, by ____, a

significant reduction in the current rate of ____ loss at global,

regional and local levels.

2002, Johannesburg, 2010, biodiversity

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