CHSE Odisha Class 12 Biology Solutions Chapter 16 Biodiversity and its Conservation

Odisha State Board CHSE Odisha Class 12 Biology Solutions Chapter 16 Biodiversity and its Conservation Textbook Questions and Answers.

CHSE Odisha 12th Class Biology Chapter 16 Question Answer Biodiversity and its Conservation

Biodiversity and its Conservation Class 12 Questions and Answers CHSE Odisha

Very Short Answer Type Questions

Multiple choice questions

Question 1.
Genetic diversity refers to
(a) variation in the genetic material
(b) variation in the populations
(c) variation in the number of species
(d) variation in the animal distribution
Answer:
(a) variation in the genetic material

Question 2.
Species diversity means
(a) number of species
(b) relative abundance of species
(c) pecies composition
(d) genetic diversities
Answer:
(b) relative abundance of species

Question 3.
The Forest Conservation Act was enacted in
(a) 1972
(b) 1952
(c) 1980
(d) 1991
Answer:
(c) 1980

Question 4.
Conservation of wild animals and plants in sanctuaries and national parks is
(a) ex situ conservation
(b) in vivo conservation
(c) in vitro conservation
(d) in situ conservation
Answer:
(d) in situ conservation

Question 5.
Corbett national park is situated in
(a) Uttarakhand
(b) Jharkhand
(c) Uttar Pradesh
(d) Himachal Pradesh
Answer:
(a) Uttarakhand

Question 6.
Following mass extinctions, recovery to the same level of biodiversity has taken
(a) hundreds of years
(b) millions of years
(c) thousand of years
(d) billions of years
Answer:
(b) millions of years

Express in one or two words

Question 1.
A species originated in one place and found no where else.
Answer:
Endemic species

Question 2.
Organism whose no living representative is seen.
Answer:
Extinct

Question 3.
Biogeographic region with high endemism and habitat destruction.
Answer:
Biodiversity hotspot.

Question 4.
Conservation of biodiversity in its natural site.
Answer:
In situ conservation.

Question 5.
Diversity of all life forms in the earth.
Answer:
Biodiversity.

Correct the statement by changing the underlined word(s)

Question 1.
Hybrid plants of a species are the source of disease resistant genes.
Answer:
Disease resistant

Question 2.
Bhitarkanika is a hotspot.
Answer:
national park of India.

Question 3.
Hotspots are characterised by low endemism and habitat destruction.
Answer:
high

Question 4.
Botanical gardens are meant for in situ conservation of biodiversity.
Answer:
ex situ

Question 5.
WWF has enlisted endangered species in Red Data Book.
Answer:
IUCN

Fill in the blanks

Question 1.
The term ‘biodiversity’ was coined by ……….. .
Answer:
Thomas E. Lovejoy

Question 2.
The three levels of biodiversity are ………… diversity, species diversity and ……….. diversity.
Answer:
genetic, ecological

Question 3.
There are ……….. numbers of megabiodiversity countries in the world.
Answer:
17

Question 4.
India had ………….. numbers of biodiversity hotspots.
Answer:
three

Question 5.
The Wildlife Protection Act was enacted in …………… .
Answer:
1972

Question 6.
The UN conference of human environment was held in ……………. in 1972.
Answer:
Stockholm

Question 7.
The expanded form of IUCN is …………….. .
Answer:
International Union of Conservation of Nature and Natural Resources.

Question 8.
The first national park of India is …………. national park.
Answer:
Hailey (Jim Corbett)

Question 9.
Odisha has ……….. numbers of national park.
Answer:
two

Question 10.
There are ………… numbers of wildlife sanctuaries in Odisha.
Answer:
19

Question 11.
India has …………. numbers of biosphere reserves.
Answer:
18

Question 12.
The concept of biosphere reserve made a beginning under ……….. programme instituted by a UN body, namely ……….. .
Answer:
Man and Biosphere (MAB), UNESCO

Short Answer Type Questions

Write short note on each of the following

Question 1.
Ecological diversity
Answer:
Ecological Diversity (Diversity among Communities):
It explains about the variety of ecosystems present in the biosphere. The community composition, i.e., assemblage of several interacting populations in a given space at a particular time is affected directly by the environment. Thus, it is the diversity at the level of communities and ecosystems of a region.

Question 2.
Wildlife Protection Act (1972).
Answer:
Wildlife Protection Act (1972) It was enacted to provide protection to wild flora and fauna and other natural resources. This act offers protection based on two approaches that are
(a) Species based approach for specific endangered species which are protected by special projects such as Project Tiger.
(b) Habitat based approach which is conservation of endangered wild flora and fauna in National Parks and Wildlife Sanctuaries.

Question 3.
In situ conservation.
Answer:
It involves the to protection of plants, animals and microorganisms within their natural ecosystems. The i in situ conservation is the most effective way of protecting the species and improving the quality of the habitat they live in. The in situ approach is preferable because of the fact that not much diversity can be conserved outside the centres of diversity.

Biodiversity at all its levels can be conserved in situ by comprehensive system of protected areas such as the national parks, wildlife sanctuaries, natural reserves, natural monuments, cultural landscapes, biosphere reserves, wetlands, etc. So far, in situ practice is considered most effective method of protecting and propagating the species and improving the quality of their habitats.

Question 4.
Ex situ conservation
Answer:
Ex situ (Off-site) Conservation:
It refers to conservation of biological diversity outside the boundaries of their natural habitats by perpetuating sample population in genetic resource centres, e.g. zoos, botanical gardens, culture collections, etc., or in the form of gene pools and gametes storage for fish, germplasm banks for seeds, pollen, semen, ova, cell, etc. Zoos also help in captive breeding of organisms which are endangered, whereas botanical gardens have seed gene banks, tissue culture labs and other technologies for storing and growing germplasm.

Question 5.
Biosphere reserve
Answer:
These are large tracts of protected land used for preserving the genetic diversity of an ecosystem by preserving wildlife. The creation of biosphere reserves was initiated in 1975 under the Man and Biosphere (MAB) programme of UNESCO. It is category V protected area designated by IUCN.

Each biosphere reserve integrates human activities and has following zonation

Core zone Strictly protected.
Buffer zone Sustainable and recreation activities allowed.
Transition zone Anthropogenic activities like research and sustainable development allowed.
Zone of human encroachment Normal anthropogenic activities allowed.

Differentiate between the following

Question 1.
In situ and Ex situ conservations.
Answer:
Differences between in situ conservation and ex situ conservation are as follows

In situ conservation	Ex situ conservation
It is the conservation of species in their natural habitats.	It is the conservation of species outside their natural habitats.
The endangered species are protected from predators.	The endangered species are protected from all adverse factors.
Augmentation of depleted resources is done.	Animals or plants are kept under human supervision and provided with all the essential necessities for survival.
e.g. national parks, sanctuaries and biosphere reserves.	e.g. zoos, botanical gardens, cultural collections, etc.

Question 2.
Genetic diversity and Species diversity.
Answer:
Differences between genetic diversity and species diversity are as follows

Genetic diversity	Species diversity
It is related to the number and type of genes and their alleles found in organisms.	It is related to the number, type and distribution of species found in given area.
It is the trait of the species.	It is the trait of the community.
It influences adaptability and distribution of a species in diverse habitat.	it influences biotic interaction and stability of the community.

Question 3.
National park and Sanctuary.
Answer:
Differences between national park and sanctuary are as follows

National park	Sanctuary
It is meant for protection of flora and fauna of the area.	It is meant for protection of one or more group of wild animals.
Cultivation of land, grazing and forestry are not allowed.	Cultivation of land, grazing and forestry are allowed.
Private ownership is not permitted.	Private ownership is permitted.
Boundary is well demarcated.	Boundary is not well demarcated.
e.g. Corbett National Park (Uttarakhand)	e.g. Bird Sanctuary Chilika (Odisha).

Question 4.
Extinct species and Endangered species
Answer:
Differences between extinct species and endangered species is as follows

Extinct species	Endangered species
A taxon is extinct when there is no reasonable doubt that the last individual has died, e.g. Indian cheetah.	A species is endangered when it is facing a very high risk of extinction in the wild in the near future, e.g. giant panda, polar bear.

Long Answer Type Questions

Question 1.
What is meant by biodiversity? Write the causes of loss of biodiversity.
Answer:
The term ‘biodiversity’ was first used by Thomas E. Lovejoy (1980) to refer the number of species of a region. It is the degree of variation of life occurring at different levels like genetic, organismal and ecological. These levels forms a hierarchy of biodiversity

Loss of Biodiversity:
The loss of biodiversity is a global crisis. Extinction of species is a natural phenomenon aided by the physical changes in the environment. However, the accelerated rates of species extinctions, that the world is facing now are largely due to human activities.
Till now, five episodes of mass extinction of species have occured in the history of biological evolution. The sixth episode of extinction of species however, is credited to human activities, which otherwise would not have occurred.

According to IUCN estimates, 12259 species have become extinct since the time of origin of life on the earth. The major cause of the biodiversity losses are called drivers, which belong to two classes namely, direct and indirect.

Direct Drivers Factors
The directly influence the ecosystem processes which bring about the mass extinction of species.
The various processes associated with direct drivers includes

1. Habitat destruction and fragmentation Conversion of forest land for agriculture, development projects, mining operation, etc., leads to the destruction of the natural habitats of the organisms.
Indiscriminate agricultural practices involving use of chemical fertilisers and pesticides are potent factors for the destruction of habitats. When a large population fragments into smaller ones there is more inbreeding and inbreeding pressure leading to population decline.

2. Overexploitation of natural resources Humans are dependent on nature for food and shelter, but when ‘need’ turns to ‘greed’, it leads to overexploitation.

To meet the need for increased housing, the natural habitats of animals and plants are being destroyed. This results in habitat loss and extinction of species. It has caused extinction of many species in last 500 years. In addition, indiscriminate hunting of wild animals has made their status in Red book as endangered or critically endangered.

3. Introduction of alien invasive species When alien species are intentionally or unintentionally introduced in a particular area, they might turn invasive and cause decline or extinction of endogenous species, e.g., Eichhornia is known as the ‘Terror of Bengal’. It was introduced as ornamental plants but it became wild in India because of invasiveness.
Similarly, Lantana and Parthenium were important due to their ornamental and food values, respectively but, they become wide spread due to favourable environmental conditions.

4. Climate change The global climate is changing, due to the anthropogenic activities like greenhouse gases and it has led to global warming. This is causing melting of glaciers, polar ice caps, etc. This may submerge low lying coastal habitats and also plants and animals are unable to adapt themselves to this change which is causing their elimination.

5. Environmental pollution It is another major factor for species extinction. Pollution may reduce and eliminate populations of sensitive species. Environmental pollution is most commonly caused by accumulation of non-biodegradeble wastes like plastics. Agricultural chemicals like pesticides enters the food chain and get deposited in the body of higher organisms. This effects the population of fish eating birds and falcons by disturbing their reproductive process.

Question 2.
How can the biodiversity be conserved? Add a note on importance of biodiversity.
Answer:
Biodiversity is directly or indirectly involved in maintaining the well-being of human society. Thus, scientists have classified the values of diversity as ecosystem goods, i.e., natural products harvested from ecosystems and directly used by humans and ecosystem services, involving different ecosystem processes which indirectly benefit human life.

Biodiversity Conservation:

The protection, uplift and scientific management of biodiversity at its optimum level for present and future generations is known as biodiversity conservation.
The International Union for Conservation of Nature and Natural Resources (IUCN) or World Conservation Union, World Wide Fund for Nature (WWF), Food and Agricultural Organisation (FAO) and United Nations Educational Scientific and Cultural_Organisation (UNESCO) formed the world conservation strategy in 1980 for the conservation and sustainable use of biological resources. For this, two major types of conservation strategies were framed. These are

1. In situ (On-site) Conservation:
It involves the to protection of plants, animals and microorganisms within their natural ecosystems. The i in situ conservation is the most effective way of protecting the species and improving the quality of the habitat they live in. The in situ approach is preferable because of the fact that not much diversity can be conserved outside the centres of diversity.

2. Ex situ (Off-site) Conservation:
It refers to conservation of biological diversity outside the boundaries of their natural habitats by perpetuating sample population in genetic resource centres, e.g. zoos, botanical gardens, culture collections, etc., or in the form of gene pools and gametes storage for fish, germplasm banks for seeds, pollen, semen, ova, cell, etc. Zoos also help in captive breeding of organisms which are endangered, whereas botanical gardens have seed gene banks, tissue culture labs and other technologies for storing and growing germplasm.

Biodiversity Preservation Methods and Sites

A protected area, as defined by IUCN, is an area (either land or sea) especially dedicated for the protection and maintenance of biological diversity through legal and ‘ other effective ways. IUCN has classified protected area into six different types. Some of these protected areas are, discussed below

National Parks:
India’s first National Park (IUCN category-II protected area) was Hailey National Park, now known as Jim Corbett National Park, established in 1935. According to National Wildlife Database, there were 103 National parks in India as in April, 2015. A national park is an area maintained by government and dedicated to conserve the environment, natural and historical objects and the wildlife therein. Operations such as plantation, cultivation, grazing forestry are not allowed in national parks. Private ownership rights and habitat manipulation are also prohibited. IUCN (1975) has adopted following keypoints to define a national park.

A national park is a relatively large area reserved for the betterment of the wildlife. The habitats of native plant and animals becomes the site of scientific, educational and recreative interests along with maintenance of its aesthetic values.
Since, human intervention is nil or limited, the operating ecosystem remains unaltered and conserved.
It is also defined as an area where the highest authority take measures to prevent exploitation and enforce conservation measures.
A place where visitors are permitted to enter only in special conditions like inspirational, cultural and recreative purposes.

Hotspots of Biodiversity:
The concept of hotspot was given by Norman Myers in 1988. Hotspots are areas that are extremely rich in species diversity, have high endemism and are under constant threat. There are 34 hotspots which cover less than 2% of earth land area of the world. In these sites nearly 75% population of world’s most threatened mammals, birds and amphibians, approximately 50% plants and 42% land vertebrates are conserved (Conservation International, 2003).

According to Myers, the key criteria for an area to be assigned as biodiversity hotspot are

It must contain atleast 0.5% or 1,500 of the world’s 3,00,000 species of vascular plants as endemics.
It should have lost atleast 70% of its primary vegetation.

Tropical forests appear in 15 hotspots, Mediterranean – type zones in 5, 9 hotspots are mainly or completely made up of islands and 16 hotspots are in the tropics. About 20 % of the human population lives in the hotspot regions.

Tropical Andes hotspot has 20,000 endemic plants and 1567 vertebrates and it is at the top of the list. Four regions of India that fulfills the criteria of hotspots are The Western Ghats and Sri Lanka, The Eastern Himalayas, Indo-Burma (North-Eastern India South of Brahmaputra river)and Sundarland (Nicobar Islands). These sites are also known as Gade of speciation.

The Western Ghats are a chain of hills that lies parallel to the Western coast of peninsular India. These regions have moist deciduous forest and rain forest and have high species diversity and high levels of endemism. Nearly 77% of the amphibians and 62% of the reptile species found here are found nowhere else. Over 6000 vascular plants of over 2500 genera are found in this hotspot, of which over 3000 are endemic.

Much of the world’s species like black pepper and cardamom have their origins in the Western Ghats. It also harbors over 450 bird species, about 140 mammalian species, 260 reptiles and 175 amphibians. Over 60% of the reptiles and amphibians are completely endemic to this hotspot.

The Eastern Himalayan hotspot has approximately 163 globally threatened species including the one-horned rhinoceros, the Wild Asian Water buffalo and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrate and 36 plant species.
Thus, hotspots are the most precious sites for biodiversity conservation and should be protected from exploitation.

Wildlife Sanctuary:
It is IUCN category IV of protected area. A wildlife sanctuary can be established by a gazette notification from the State Forest Department, where protection is provided to vulnerable, endangered and critically endangered wild animals life. Operations such as procuring timber and minor forest products and private ownership are allowed provided they do not cause any adverse effects on the animals. Till 2015, there were 520 wildlife sanctuaries in India, covering 122867.34 km2 (3.74%) of land in India. The state of Odisha has 19 wildlife sanctuaries, which are listed below
CHSE Odisha Class 12 Biology Solutions Chapter 16 Biodiversity and its Conservation 2

Biosphere Reserve:
These are large tracts of protected land used for preserving the genetic diversity of an ecosystem by preserving wildlife. The creation of biosphere reserves was initiated in 1975 under the Man and Biosphere (MAB) programme of UNESCO. It is category V protected area designated by IUCN. Today, India has 18 biosphere reserves, some of which are also included under National Parks and Odisha has a share of one in Simlipal.

Each biosphere reserve integrates human activities and has following zonation

Core zone Strictly protected.
Buffer zone Sustainable and recreation activities allowed.
Transition zone Anthropogenic activities like research and sustainable development allowed.
Zone of human encroachment Normal anthropogenic activities allowed.

Out of 18 biosphere reserves, 8 of them are a part of world network of Biosphere Reserves based on MAB Programme of UNESCO.

The objectives of this programme are

Conserving representative samples of ecosystems.
In situ conservation of genetic diversity.
Facilitating basic and applied research in ecology and environmental biology on site.
Create opportunities for environmental education k and training.
Promoting and creating awareness about sustainable management of living resources.
Promoting international cooperation.

Therefore, the biosphere reserves have three junctions, that includes

Conservation of ecosystems and genetic variations.
Promotion of sustainable economic and human development.
They serve as examples of education and training local, regional, national and international issues of sustainable development.

A protected area to be declared as a biosphere reserve should have the following essential features

Abundant genetic diversity should be present.
It should be unique in itself.
The area should be legally protected for long term.
Appropriate size for effective maintenance of natural populations so that there is no genetic drift.
Sufficient natural resource available for ecological research, education and training. It should be a natural home for the endangered species of plants and animals.

Question 3.
Give an account of biodiversity and its conservation measures.
Or
Give an account of the concept of biodiversity.
Answer:
The term ‘biodiversity’ was first used by Thomas E. Lovejoy (1980) to refer the number of species of a region. It is the degree of variation of life occurring at different levels like genetic, organismal and ecological. These levels forms a hierarchy of biodiversity. The integration of several sciences such as ecology and genetics to sustain biological diversity at all its levels is called conservation biology.

Levels of Biodiversity

In 1986, Norse and Me Manus explained the three levels of biodiversity. These include

1 Genetic Diversity:
It involves variations in genetic composition among the individuals of a species. This variations could be in the nucleotides, genes, entire genome or chromosomes. This type of diversity arises due to genetic recombination during sexual reproduction and mutation.

Variations in the genes of a species increases with the increase in size and environmental parameters of the habitat. Genetic diversity is useful as it helps an individual to adapt to changing environmental condition, natural selection and is essential for healthy breeding. It also helps in speciation or evolution of new species.

2. Organismal or Species Diversity (Diversity among Species):
It is the variety in the number and richness of a species of a region. Sometimes, a species remains confined to a particular area and is found only in that area. Such species are said to be endemic, e.g., Indian giant squirrel is endemic to Panchmarhi hills in Madhya Pradesh.

The IUCN (International Union for Conservation of Nature and Natural Resources) recognises three types of species diversity, i.e.

Alpha (α) diversity It refers to the variety of species within a community. It is also referred to as species richness, i.e., the number of species per unit area.
Beta (β) diversity It refers to the diversity of species among communities.
Gamma (γ) diversity It refers to the diversity of species across a wide geographical range.

The important features of species diversity to the ecosystem are as follows

Increased biodiversity provides resistance to the ecosystem against natural disasters.
Ecosystem with more species shows more yields and greater productivity with variation of biomass.
Community with more species generally tends to be more stable than those with less species.

3. Ecological Diversity (Diversity among Communities):
It explains about the variety of ecosystems present in the biosphere. The community composition, i.e., assemblage of several interacting populations in a given space at a particular time is affected directly by the environment. Thus, it is the diversity at the level of communities and ecosystems of a region.

Patterns of Biodiversity

Biodiversity is not uniform throughout the world. It varies with the changes in latitude and altitude. For many groups of animals and plants, there are specific patterns in diversity based on the favourable environmental conditions.
The pattern of biodiversity among different regions is discussed below

Latitudinal Gradients:
Species diversity decreases as we move away from the equator towards the poles. It means biodiversity is more at lower latitude (equator) than the higher latitude (poles). The biodiversity gradient is steep in Northern hemisphere than the Southern hemisphere.

Biodiversity in Tropics
Tropics (latitudinal range of 23.5°N to 23.5°S) harbour more species than temperate or polar areas, e.g., Colombia located near the equator, has 1,400 species of birds.

New York located at 41°N has 105 species of birds, while Greenland at 71°N has only 56 species of birds. India, with most of its area in tropical latitude has more than 1200 species of birds. A forest of equal area in tropical region (like equator) has 10 times more species of vascular plants than in temperate region (like Mid-West of USA). Amazonian rainforest in South America has the greatest biodiversity on the earth with more than 40,000 species of plants, 3,000 of fishes, 1,300 of birds, 427 of mammals and amphibians, 378 of reptiles and more than 1,25000 of invertebrates.

Reasons for Greater Biodiversity in Tropics
The factors making tropical rainforests rich in biodiversity are

Tropical latitudes have remained undisturbed for million of years allowing speciation.
Tropical environments are relatively constant throught the year which promotes niche specialisation and greater diversity.
High productivity leads to greater diversity. It is also found that species diversity increases with area (species area curves), how it peaks in areas with intermediate productivity or intermediate rates of disturbance. The more variable the habitat, the greater the species diversity within it. This pattern was offered as one of the reasons why there are more species in bigger area as more area covers a greater variety of habitat.

Importance of Biodiversity

Biodiversity is directly or indirectly involved in maintaining the well-being of human society. Thus, scientists have classified the values of diversity as ecosystem goods, i.e., natural products harvested from ecosystems and directly used by humans and ecosystem services, involving different ecosystem processes which indirectly benefit human life.

Direct Value

Food It includes all the plant and animal products used as food by humans, e.g., cereals, pulses, vegetables, fruits, milk, beverages, etc.
Clothing It includes natural fabric made out of cotton, jute and natural silk (harvested from silk moth).
Shelter It includes raw material obtained from ecosystem for making houses, e.g., wood, etc.
Medicines Large number of substances with therapeutic properties are obtained from variety of plant species and animals, e.g.
1. Quinine Antimalarial drug, obtained from the bark of Cinchona plant.
2. Anticoagulants Antihemorrhagic drugs, extracted from blood sucking animals.
3. Snake venom and toxins Drugs for neural and muscular disorders.
4. Penicillin, tetracyclins and streptomycins Antibiotics extracted from microorganisms.
5. Biocidal compounds Used in manufacturing antibiotics, extracted from beetles, millipedes, snails and ants.
Industrial products A variety of industrial products are directly made out of biological resources, e.g. timber, fuel, dyes, oil, etc., from plants and leather, etc., from animals skin.

Indirect Value:

1. Biological control It is the use of microorganisms for the manufacture of antibiotics, oral contraceptives, etc., and management of pests, increasing soil fertility, cleaning oil spill (super bug), treatment of sewage and solid waste, recovery of metals (bioleaching), monitoring pollution generating biofuel, etc.

2. Environmental modulation. It includes some animals and plants which influence and modulate the environment directly and indirectly. Such animals and plants are known as ecosystem engineers. One of these are keystone species whose extinction reduces abundance of other species in the community.

A well known example of ecosystem engineer is beaver (a mammal). It influence plant and animal communities and the entire biodiversity of watershed area by
(a) Creating dams using logs in river channels
(b) Modifying nutrient cycling
(c) Influencing decomposition dynamics.

3. Ecosystem functions and services Biodiversity plays a major role in many ecosystem services and functions such as replenishing oxygen through photosynthesis, pollination through bees, regulation of global climate, retention of rainwater in aquifers and reservoir, control of floods, etc.
Nature always key a check on these activities to maintain a state of equilibrium (homeostasis), which further helps in the sustainable development of resources. However, overexploitation of biolgical resources by humans leads to destabilisation of ecosystem balance.
For example,

Decreased flora of an area leads to CO₂ increase in the atmosphere which causes temperature elevation of that area.
Increased carnivore population decreases the herbivore population by predation which then increase the vegetation.
Declined population of microflora prevents the recycling between complex organic matter and simple inorganic matter.

4. Ecotourism The diverse biological resource of a country motivates people from around the world to undertake recreational activities like tours to enjoy the diverse wildlife and charismatic landscape. In return the host country earns a large sum of foreign exchange as revenue.

Loss of Biodiversity

The loss of biodiversity is a global crisis. Extinction of species is a natural phenomenon aided by the physical changes in the environment. However, the accelerated rates of species extinctions, that the world is facing now are largely due to human activities.

Till now, five episodes of mass extinction of species have occured in the history of biological evolution. The sixth episode of extinction of species however, is credited to human activities, which otherwise would not have occurred.

Direct Drivers Factors

The directly influence the ecosystem processes which bring about the mass extinction of species.
The various processes associated with direct drivers includes

1. Habitat destruction and fragmentation Conversion of forest land for agriculture, development projects, mining operation, etc., leads to the destruction of the natural habitats of the organisms.
Indiscriminate agricultural practices involving use of chemical fertilisers and pesticides are potent factors
for the destruction of habitats. When a large population fragments into smaller ones there is more inbreeding and inbreeding pressure leading to population decline.

2. Overexploitation of natural resources Humans are dependent on nature for food and shelter, but when ‘need’ turns to ‘greed’, it leads to overexploitation.
To meet the need for increased housing, the natural habitats of animals and plants are being destroyed. This results in habitat loss and extinction of species. It has caused extinction of many species in last 500 years. In addition, indiscriminate hunting of wild animals has made their status in Red book as endangered or critically endangered.

Similarly, Lantana and Parthenium were important due to their ornamental and food values, respectively but, they become wide spread due to favourable environmental conditions.

Indirect Drivers
These influences or changes one or more the direct driver. They include

Population growth Rapid increase in human population causes loss of biodiversity becatise population explosion results in rapid growth of exploitation of natural resources such as water, food and minerals. If this trend of population growth continue, the resources will be depleted faster and most species will face the risk of extinction.
Income and lifestyle Today people’s income has increased tremendously which has led to more luxurious lifestyle of people. For leading this, they tend to use more and more of natural resources which causes pollution, degradation of environment and biodiversity loss.

Extinction of Species

In the history of earth many species have disappeared and new ones got evolved over million of years. The major threat to biodiversity is extinction of species Extinction is the total elimination or dying out of species (fossilisation) form the earth. As, we already know, the extinction of species is a natural process which accelerates due to human activities.

There are generally three types of extinction
1. Natural extinction It is a slow process of replacement of existing species with the better adapted species due to alternate evolution, changes in environmental condition, predation and diseases. Extinction of species occurs due to combination of genetic and demographic factors.

2. Mass extinction It occur due to catastrophes, which struck the earth several times. A mass extinction occurred about 225 million years ago in Permian period when 90% of shallow marine invertebrates disappeared.
Another mass extinction occurred between cretaceous and tertiary period over 60 million years ago when dinosaurs and a number of other organisms disappeared.

3. Anthropogenic extinction These are extinction of organisms due to human activities like hunting, overexploitation and habitat destruction, e.g. dodo (Raphus cucullatus), Tasmanian wolf, etc. Anthropogenic extinction is causing a sixth extinction of species. It is 100-1000 times more faster than the rate of natural extinctions.

IUCN and Red List
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. IUCN maintains a Red Data Book (RDB) or Red List which is a catalogue of taxa facing risk of extinction. Red Data Book was initiated in 1963.
The purpose of red list is to

(i) Provide awareness to the degree of threat to biodiversity.
(ii) Provide global index about already declined of biodiversity.
(iii) Identification and documentation of species at high risk of extinction.
(iv) Preparing conservation priorities and help in conservation plan.
(v) Information about international agreements like conservation on biological diversity and CITES (Convention on International Trade in Endangered Species) of Wild Fauna and Flora.

The IUCN Red List 2004 has recorded a total loss of 784 species in the last 500 years. These include 733 animals (mostly vertebrates and molluscs), 110 plants and one red alga. The extinction of dodo in Mauritius, quagga in Africa were notable extinctions in the recent years.

The species that became extinct in 2003 was the plant Nesiota elliptica, St. Helena Olive (a small tree in Saint Helena Island) in the South Atlantic Ocean. The IUCN red list of threatened species founded in 1964, is the worlds most comprehensive inventory of global conservation status of biological species.The IUCN Red List has listed 132 species of plants and animals from India as ‘Critically Endangered’.

Red List assign categories to each species. These are as follows

Extinct A taxon is extinct when there is no reasonable doubt that its last individual has died, e.g. dodo, Indian cheetah.
Extinct in the Wild (EW) A number of domesticated animals and plants have become extinct in the wild. A taxon is extinct in the wild when it is known to survive only under cultivation.
Critically Endangered (CR) A taxon is critically , endangered when it is facing an extremely high risk of extinction in the wild in immediate future (925 animals and 1014 plants), e.g, One horned rhinoceros.
Endangered (EN) A taxon is endangered when it is not critically endangered, but facing a very high risk of extinction in the wild in near future, e.g, Giant panda and polar bear.
Vulnerable (VU) A taxon is vulnerable when it is not critically endangered or endangered, but it is facing a high risk of extinction in the wild in the medium term future, e.g. sparrow.
Threatened Species is the one which is liable to become extinct if not allowed to realise its full biotic potential by providing protection from the exotic species, e.g. in black buck.
Low Risk (LR) A taxon is at low risk when evaluated, it does not qualify for any of the categories like critically endangered, endangered or vulnerable.
Data Deficient (DD) A taxon is data deficient when there is inadequate information to make a direct or indirect assessment of its risk of extinction based on its distribution or population status.
Not Evaluated (NE) A taxon is under the category of not evaluated, when it has not yet been assessed against above criteria.

Biodiversity Conservation:

Biodiversity Preservation Methods and Sites

A national park is a relatively large area reserved for the betterment of the wildlife. The habitats of native plant and animals becomes the site of scientific, educational and recreative interests along with maintenance of its aesthetic values.
Since, human intervention is nil or limited, the operating ecosystem remains unaltered and conserved.
It is also defined as an area where the highest authority take measures to prevent exploitation and enforce conservation measures.
A place where visitors are permitted to enter only in special conditions like inspirational, cultural and recreative purposes.

According to Myers, the key criteria for an area to be assigned as biodiversity hotspot are

It must contain atleast 0.5% or 1,500 of the world’s 3,00,000 species of vascular plants as endemics.
It should have lost atleast 70% of its primary vegetation.

Each biosphere reserve integrates human activities and has following zonation

Core zone Strictly protected.
Buffer zone Sustainable and recreation activities allowed.
Transition zone Anthropogenic activities like research and sustainable development allowed.
Zone of human encroachment Normal anthropogenic activities allowed.

Out of 18 biosphere reserves, 8 of them are a part of world network of Biosphere Reserves based on MAB Programme of UNESCO.

The objectives of this programme are

Conserving representative samples of ecosystems.
In situ conservation of genetic diversity.
Facilitating basic and applied research in ecology and environmental biology on site.
Create opportunities for environmental education k and training.
Promoting and creating awareness about sustainable management of living resources.
Promoting international cooperation.

Therefore, the biosphere reserves have three junctions, that includes

Conservation of ecosystems and genetic variations.
Promotion of sustainable economic and human development.
They serve as examples of education and training local, regional, national and international issues of sustainable development.

A protected area to be declared as a biosphere reserve should have the following essential features

Abundant genetic diversity should be present.
It should be unique in itself.
The area should be legally protected for long term.
Appropriate size for effective maintenance of natural populations so that there is no genetic drift.
Sufficient natural resource available for ecological research, education and training. It should be a natural home for the endangered species of plants and animals.

CHSE Odisha 12th Class Biology Chapter 16 Question Answer Biodiversity and its Conservation

Biodiversity and its Conservation Class 12 Questions and Answers CHSE Odisha

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