SEM II, AECC-2, Environmental Science, Unit 4 Compiled by ...

SEM II, AECC-2, Environmental Science, Unit 4 Compiled by Dr. Jayanta Sikdar

Assistant Professor

Surendranath College

24/2 M.G. Road, Kolkata, West Bengal 700009

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Unit 4: Biodiversity & Conservation

What is biodiversity?

Biodiversity is “the variety of all living things, and the systems which connect them.” This

includes all the planet's different plants, animals and micro organisms, plus the genetic

information they contain and the ecosystems of which they are a part. It is the result of millions

of years of evolution.

Significance of Biodiversity:

Biodiversity, besides its ecological significance provides a socio-economic and monetary asset to

the nation. Human society depends on biological resources, their diversity and the ecosystems

that sustain them to provide essential goods and services.

Level of Biodiversity:

1. Species diversity

Species diversity refers to biodiversity at the most basic level and is the „variety and

abundance of different types of individuals of a species in a given area‟. It includes all the

species on Earth, ranging from plants such as bacteria, viruses, fungi, algae,

bryophytes, pteridophytes, gymnosperms, angiosperms and all the species of

animals including unicellular protozoans to mammals.

2. Genetic diversity

„Genetic diversity pertains to the range of diversity in the genetic resources of the

organisms‟. Every individual member of a plant or animal species differs from other

individuals in its genetic constitution. Each individual has specific characters, which is


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due to the genetic makeup or code. The genes present in the organisms can form

infinite number of combinations that causes genetic variability.

The term ‘gene pool’ has been used to indicate the genetic diversity in the different

species. This also includes the diversity in the wild species, which through intermixing in

nature over millions of years have given rise to newer varieties. The domesticated

varieties of agricultural crops and animals have also evolved from the wild gene pool.

3. Ecological diversity

Each ecosystem consists of organisms from many different species, living together in a

region connected by the flow of energy and nutrients. The Sun is the ultimate source of

energy for all the ecosystems. The Sun’s radiant energy is converted to chemical energy

by plants. This energy flows through the different systems when animals eat the plants

and then are eaten, in turn, by other animals. Fungi and bacteria derive energy from the

decomposing dead organisms, releasing nutrients back into the soil as they do so.

Biogeographic Classification of India:

Our country can be conveniently divided into ten major regions, based on the geography,

climate and pattern of vegetation seen and the communities of mammals, birds, reptiles,

amphibia, insects and other invertebrates that live in them. Each of these regions contains

a variety of ecosystems such as forests, grasslands, lakes, rivers, wetlands, mountains and

hills, which have specific plant and animal species.

India’s Biogeographic Zones

1. The cold mountainous snow covered Trans Himalayan region of Ladakh.

2. The Himalayan ranges and valleys of Kashmir, Himachal Pradesh, Uttarakhand,

Assam and other North Eastern States.

3. The Terai, the lowland where the Himalayan rivers flow into the plains.

4. The Gangetic and Bhramaputra plains.

5. The Thar Desert of Rajasthan.


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6. The semi arid grassland region of the Deccan plateau Gujarat, Maharashtra, Andra

Pradesh, Karnataka and Tamil Nadu.

7. The Northeast States of India,

8. The Western Ghats in Maharashtra, Karnataka and Kerala.

9. The Andaman and Nicobar Islands.

10. The long western and eastern coastal belt with sandy beaches, forests and mangroves

Hotspots of Biodiversity:

The earth‟s biodiversity is distributed in specific ecological regions. There are over a

thousand major ecoregions in the world. Of these, 200 are said to be the richest, rarest

and most distinctive natural areas. These areas are referred to as the Global 200. It has

been estimated that 50,000 endemic plants which comprise 20% of global plant life,

probably occur in only 18 ‘hot spots’ in the world. Countries which have a relatively

large proportion of these hot spots of diversity are referred to as ‘megadiversity

nations’. The rate at which the extinction of species is occurring throughout our country

remains obscure. It is likely to be extremely high as our wilderness areas are shrinking

rapidly. Our globally accepted national ‘hot spots’ are in the forests of the North-East

and the Western Ghats, which are included in the world‟s most biorich areas. The

Andaman and Nicobar Islands are extremely rich in species and many subspecies of

different animals and birds have evolved. Among the endemic species i.e. those species

found only in India, a large proportion is concentrated in these three areas. The Andaman

and Nicobar Islands alone have as many as 2200 species of flowering plants and 120

species of ferns. Out of 135 genera of land mammals in India, 85 (63%) are found in the

Northeast. The Northeast States have 1,500 endemic plant species. A major proportion

of amphibian and reptile species, especially snakes, are concentrated in the Western

Ghats, which is also a habitat for 1,500 endemic plant species. Coral reefs in Indian

waters surround the Andaman and Nicobar Islands, Lakshadweep Islands, the Gulf areas

of Gujarat and Tamil Nadu. They are nearly as rich in species as tropical evergreen

forests.


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India as a Mega Diversity Nation:

Geological events in the landmass of India have provided conditions for high levels of

biological diversity. A split in the single giant continent around 70 million years ago, led

to the formation of northern and southern continents, with India a part of Gondwanaland -

the southern landmass, together with Africa, Australia and the Antarctic. Later tectonic

movements shifted India northward across the equator to join the Northern Eurasian

continent. As the intervening shallow Tethis Sea closed down, plants and animals that

had evolved both in Europe and in the Far East migrated into India before the Himalayas

had formed. A final influx came from Africa with Ethiopian species, which were adapted

to the Savannas and semi-arid regions. Thus India‟s special geographical position

between three distinctive centers of biological evolution and radiation of species is

responsible for our rich and varied biodiversity. Among the biologically rich nations,

India stands among the top 10 or 15 countries for its great variety of plants and animals,

many of which are not found elsewhere. India has 350 different mammals (rated eight

highest in the world), 1,200 species of birds (eighth in the world), 453 species of reptiles

(fifth in the world) and 45,000 plant species, of which most are angiosperms, (fifteenth

in the world). These include especially high species diversity of ferns (1022 species) and

orchids (1082 species). India has 50,000 known species of insects, including 13,000

butterflies and moths. It is estimated that the number of unknown species could be

several times higher. It is estimated that 18% of Indian plants are endemic to the

country and found nowhere else in the world. Among the plant species the flowering

plants have a much higher degree of endemism, a third of these are not found elsewhere

in the world. Among amphibians found in India, 62% are unique to this country.

Among lizards, of the 153 species recorded, 50% are endemic. High endemism has also

been recorded for various groups of insects, marine worms, centipedes, mayflies and

fresh water sponges.

Apart from the high biodiversity of Indian wild plants and animals there is also a great

diversity of cultivated crops and breeds of domestic livestock. This is a result of several

thousand years during which civilizations have grown and flourished in the Indian

subcontinent. The traditional cultivars included 30,000 to 50,000 varieties of rice and a

number of cereals, vegetables and fruit. The highest diversity of cultivars is concentrated

in the high rainfall areas of the Western Ghats, Eastern Ghats, Northern Himalayas and

the North-Eastern hills. Gene-banks have collected over 34,000 cereals and 22,000


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pulses grown in India. India has 27 indigenous breeds of cattle, 40 breeds of sheep,

22 breeds of goats and 8 breeds of buffaloes.

India‟s World Number of Ranking species in India Mammals 8th 350 Birds 8th 1200

Reptiles 5th 453 Amphibia 15th 182 Angiosperms 15th-20th 14,500

What is Endemic Species?

Endemic species are those that are found in just one region and nowhere else in the world. For

example, kangaroos are originally endemic to Australia and are found nowhere else in the world.

The cases where they have been spotted outside their natural habitat are due to humans

introducing them when the animal was in captivity.

There are also other marsupials that are endemic only to Australia and its surrounding islands.

The Tasmanian tiger is one such animal that was endemic to Australia, Tasmania and New

Guinea. But now, it is extinct.

Endemic Species of India

A list of the endemic species of India is mentioned below:

Asiatic Lion, Gir Forest

Asiatic Lion is also known as the Indian Lion and can be only found in and around Gir Forest

National Park of Gujarat. These are listed as endangered species. These are one of the five big

cats found in India, the others being Indian Leopards and Bengal Tigers.

Kashmir Stag, Kashmir Valley

Also known as Hangul, Kashmir Stag is found in the dense forests of Dachigum National Park,

Kasmir Valley and Chamba district, Himachal Pradesh.

Lion-Tailed Macaque, Western Ghats

It is the rarest and the most threatened and endangered primate species found only in the Western

Ghats of Southern India.

Purple Frog, Western Ghats

The purple frog, also known as Pignose frog is only found in the rainforests of western ghats in

India. It spends most of its life underground.

Sangai Deer, Loktak Lake

It is also known as Brow Antlered Deer exclusively found in Keibul Lamjao National Park of

Manipur. This park is a marshy wetland located in the southern parts of Loktak lake.


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Nilgiri Tahr, Nilgiri Hills

It is a wild sheep species, endangered and endemic to the Nilgiri Hills of Western Gats.

Other endemic species of India include:

Pygmy Hog, Assam

Bronzeback Vine Snake, Western Ghats

Nilgiri Blue Robin, Nilgiri Hills

Malabar Civet, Western Ghats

Anaimalai Gliding Frog, Anaimalai Hills

Namdapha Flying Squirrel, Arunachal Pradesh

Indian Giant Squirrel

Bonnet Macaque

Endemic plant species in India

Abutilon ranadei, Achyranthus coynei, Barleria sepalosa, Ascopholis campbellia, Jerdonia,

Andropogon longipes, Acacia donaldii, Mucuna minima, Oryza jeyporensis etc.

Threats to Biodiversity:

Habitat loss is mainly due to human population growth, industrialization and changes in the land

use patterns, poaching of wild life and man wildlife conflicts. Man has begin to overuse or

misuse most of these natural ecosystems. Due to unsustainable resource-use, once productive

forests and grasslands have been turned into deserts and wastelands have been increased all over

world. Scientists have estimated that human activities are likely to eliminate approximately 10

million species by the year 2050.

Endangered species:

These endangered species have been categorized into four viz, 1)Vulnerable, 2) Rare, 3)

Intermediate, 4) Threatened. Endangered species which are on verge of extinction are called

threatened species. Most of the endangered species, are found today only in protected areas

(PAs). Some examples of the species being Tiger, rhino, elephant; bird species include

Siberian crane, great Indian bustard, Florican, vultures; reptiles and amphibians. Habitat

loss caused by human activity is causing threat to plants species like orchids. Over harvesting as

ingredients in medical products or cosmetics is also threatening species. To protect endangered

species India has created a wildlife protection act. Under this plants and animals are

characterized according to thereat to their survival. The species which are unique to a


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locality/region are called endemic species. Some species are found only in India and are thus

endemic (restricted to our country). Some have very localized distribution and are considered

highly endemic. Some species of this category being Indian wild ass, angular kashmiri stag,

golden langur, pigmyhog.

Human population growth, industrialization and changes in the land use patterns:

Around 1.8 million species of plants and animals are known to science. The actual number of

species have been existing is more than 10x1.8millions. Though new species have been

continually identified, the rate of extinction is very high (10-20,000 species per year that is 1000

to 10,000 times faster rate). Human actions are expected to exterminate 25% of world‟s species

in next 20-30 years. The mega extinction spasm is related to human population growth,

industrialization and changes in the land use patterns in India.

The reasons are:

1. Forests and grasslands are changed to agricultural land. Encroachments are being

repeatedly legalized.

2. Natural wetlands are drained to establish crop lands leading to loss of aquatic species.

3. Mangroves have been cleared for fuel wood and prawn farming, which has led to

decrease in the habitat essential for breeding of marine fish.

4. Grasslands are changed to other forms, degraded by overgrazing. Loss to cattle, goat and

sheep.

5. Natural forests are being deforested for timber and replanted for teak, sal etc. Such

monoculture does not support biodiversity as in forests which have closed canopy and

rich undergrowth. Excess collection of fire wood by lopping of branches of trees canopy

is opened up altering the local biodiversity.

6. Foraging cattle retard regeneration of forest as young seedlings are trampled.

7. Ever increasing population gradually decreases buffer zones and forested areas. A prime

example is Gir national park, the last bastion of Asiatic lion with a meter gauge railway

line, state expressway and 3 temples.

8. Repeated fires by local grazers to increase growth of grass ultimately reduce regeneration

of grasses.

9. Introduction of exotic weeds eg. Lantana bushes, Eupatorium shrubs and „congress‟ grass

is invading at the expense of indigenous undergrowth species. Following traditional


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farming techniques like slash and burn in Himalayas, and rab, lopping of tree branches

for making wood ash fertilizer in Western ghats are now leading to loss of biodiversity.

10. Over harvesting of fish by large trawling boats is leading to depletion of fish stocks.

Poaching:

Specific threats to certain animals are related to large economic benefits. The skin and bones

from tigers, ivory from elephants, horns from rhinos and perfume from the musk deer are

extensively used abroad. Bears are killed for their gall bladders. Corals and shells are also

collected for export or sold on the beaches of Chennai, Kanyakumari and the Andaman and

Nicobar islands. Tortoises, exotic birds and other small animals are packed into tiny containers

and smuggled abroad for the pet trade. A variety of wild plants with real or sometimes, dubious

medicinal values are being overharvested. The commonly collected plants include Rauwolfia,

Nux vomica, Datura etc. The garden plants collected for illegal trade include orchids, ferns and

mosses.

Man wild life conflicts:

Conflicting situations with wild life starts causing immense damage and danger to man. Ex: In

Sambalpur, Orissa 195 humans are killed in last 5 years by elephants and in retaliation villagers

killed 98 elephants and badly injured more than 30 elephants. Similar incidents with tigers,

leopards etc. are in news. Shrinking forest cover, human encroachment, ill and weak animals,

lack of food (one adult elephant needs 200 kg green fodder and 150 kg of clean water) for

animals, protecting villagers by putting electric fence are the main reasons for such happenings.

As the compensation by government. is not enough, conflicts occur between forest department

and villagers.

Conservation of biodiversity:

Two types: In situ and Ex situ

In situ conservation: Conserving a species in its own environment by creating national parks

and wildlife sanctuaries. Habit is protected with all the other spp that in it in nature Biodiversity

at all levels can be best preserved in situ by setting aside wildness as protected areas (in national

parks and wildlife sanctuaries) with distinctive ecosystem included in the network. Such net

work preserves the total diversity of life of the region.


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Biologists view point is to deal with areas which are 1) Species rich 2)

Rare/threatened/endangered species / endemic species are found should be given importance

as there spp would easily become extinct due to human activity. For examples Elephants utilize

open grasslands after the rains (when it is nutritious) but move into forest to feed on foliage in

dry season. Hence protected areas for elephant must be large to include a diverse habitat that

supports a complete complement of interlinked species.

India has 589 PAs (protected areas) of which 89 are national parks and 500 are wildlife

sanctuaries. Over 100 PAs are created in Andaman and Nicobar to preserve the special island

ecosystem. The great Himalayan national park is the largest sanctuaries in the ecosystem and is

the home of snow leopard. Dachigam sanctuary for hangul or kashmiri stag; Kaziranga national

park for animals like elephant, guar, wild boar and swamp deer, and birds like ducks geese,

pelicans and storks; Manas sanctuary for golden langur, pigmy hog and wild boar are some of

the examples worth mentioning under in situ conservation.

Ex situ conservation: Conserving the species outside the natural habitat in a carefully controlled

situation, such as botanical garden for plants or zoological parks for animals, expertise exists to

multiply species under artificially managed condition. Gemplasm is preserved in a gene bank

for future need, this is taken up for expensive endangered /extinct species. Care is taken to

avoid inbreeding such that weak offspring would not develop. Breeding programmes in zoos

provide animal needs including enclosures that simulate their wild habitat. Modern zoo‟s

function is to breed endangered species as conservation. Successful examples are 1. Madras

crocodile trust bank has successfully bred the 3 crocodiles. Here crocodiles lay two clutches

of eggs in one year year instead of one in wild. 2. Guchali zoo has bred pigmy hog 3. Delhi

zoo has bred the rare Manipur brow antlered deer. The successful breeding programme also

aims at reintroduction of the species into wild habitat, with simultaneous removal of problems

like poaching disturbances and man made influences.

Source: https://www.ugc.ac.in/oldpdf/modelcurriculum/Chapter4.pdf

http://ecoursesonline.iasri.res.in/mod/page/view.php?id=128623

https://www.ugc.ac.in/oldpdf/modelcurriculum/Chapter4.pdf

http://ecoursesonline.iasri.res.in/mod/page/view.php?id=128623


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1. Biodiversity is a measure of variation at the ___ level. (A) genetic

(B) species

(C) ecosystem

(D) all of the above

2. Terrestrial biodiversity is usually greater near the ___ . (A) north pole

(B) south pole

(C) equator

(D) tropic of cancer

3. The tropical forest ecosystems cover less than 10 percent of earth’s surface, and contain

about ___ percent of the world’s species. (A) 30

(B) 50

(C) 70

(D) 90

4. The age of earth is about ___ billion years. (A) 3.04

(B) 3.54

(C) 4.05

(D) 4.54

5. Following is usually measured at the species diversity level. (A) ecological diversity

(B) taxonomic diversity

(C) morphological diversity

(D) functional diversity

6. Diversity of all living things depends on (A) geography

(B) presence of other species

(C) soils


7. A biodiversity hotspot (A) is a region with a high level of endemic species

(B) that have experienced great habitat loss

(C) both (A) and (B)

MCQ Questions


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(D) none of the above

8. Which of the following is true (A) land has more species than the ocean

(B) ocean has more species than the land

(C) land and ocean has almost equal number of species

(D) not yet known

9. Provisioning services (A) involve the production of renewable services

(B) are those that lessen environmental change

(C) represent human value and enjoyment


10. Provisioning services of (A) plants increases fodder yield

(B) plants increases overall crop yield

(C) trees increases overall wood production


11. Regulating services of plants (A) decreases disease prevalence on plants

(B) increases resistance to plant invasion

(C) increases soil nutrient remineralization


12. Biodiversity is directly involved in (A) water purification

(B) recycling nutrients

(C) providing fertile soil


13. The most studied group is (A) birds

(B) mammals

(C) both (A) and (B)

(D) fishes

14. The species which occupy new territory, often supplanting native species by occupying

their niches, are called (A) invasive species


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(B) extinct species

(C) endangered species

(D) exotic species

15. Following step(s) can conserve the forest cover (A) prevent forest fire

(B) prevention of overgrazing by cattle

(C) hunting and poaching should be banned


16. How many biogeographic does India have?

1. 5

2. 6

3. 8

4. 10

17. Lime is generally added to _____ soil

1. Salty

2. Dry

3. Alkaline

4. Acidic

18. _______ has the maximum genetic diversity in India

1. Potato

2. Tea

3. Mango

4. Teak

19. _________ is one of the most prevalent hotspots of biodiversity in India

1. Himalayas

2. Western Ghats

3. Ganges

4. None of the above

20. Galápagos finches are a good example of ____________

1. Extinction

2. Heterochromia

3. Island gigantism

4. Adaptive radiation


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21. ______ is one of the least porous soils

1. Peat Soil

2. Loam

3. Clayey soil


22. ___________ is a non-renewable resource

1. Crude oil

2. Uranium

3. Hot spring

4. Silica

23. __________ is an example of an ex-situ conservation.

1. Sacred groves

2. Wildlife sanctuary

3. Seed bank

4. National park

24. __________ is not generally seen in biodiversity hotspots.

1. Endemism

2. Species richness

3. Loss of diversity

4. Lesser interspecific competition.

25. ___________ occurs when the death of the last individual in a species occurs.

1. Adaptation

2. Phylogenic diversity

3. Speciation

4. Extinction

26. ____________ is defined as an ecological state of a species being unique to a specific

geographic location.

1. Exotic species

2. Endemic species

3. Ecosystem



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27. _________ is the forest cover to be maintained as per the National Forest Policy (1988)

1. 67% for hills & 33% for plains




28. ___________ is defined as the number of species represented in a specific region,

landscape or an ecological community.

1. Coevolution

2. Commensalism

3. Species richness

4. Population density

29. Global warming can be controlled by _____________

1. Reducing solid waste

2. Reducing water wastage

3. Burning human-generated waste

4. Reducing fossil fuel consumption

30._______ is the basic unit of classification and a taxonomic rank

1. Species

2. Genus

3. Class

4. Order

31. Which of the following animals is now extinct?

1. Tasmanian tiger

2. Tasmanian devil

3. Pademelon

4. Quoll

SEM II, AECC-2, Environmental Science, Unit 4 Compiled by ...

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