GSEB Solutions Class 12 Biology Chapter 15 Biodiversity and Conservation

Gujarat Board GSEB Textbook Solutions Class 12 Biology Chapter 15 Biodiversity and Conservation Textbook Questions and Answers, Additional Important Questions, Notes Pdf.

Gujarat Board Textbook Solutions Class 12 Biology Chapter 15 Biodiversity and Conservation

GSEB Class 12 Biology Biodiversity and Conservation Text Book Questions and Answers

Question 1.
Name the three important components of biodiversity.
Answer:

1. Genetic biodiversity
2. Species diversity
3. Ecological diversity

Question 2.
How do ecologists estimate the total number of species present in the world?
Answer:
It is difficult to answer that how many species are there on earth. According to the IUCN (International Union of Conservation of Nature), the total number of animal and plant species is more than 1.5 million. It is doubtful that how many of the species are yet to be discovered and described. For many taxonomic groups, species inventories are more complete in temperate than in tropical countries.

Many of the species waiting to be discovered are in the tropics. Biologists often make a statistical comparison of the temperate-tropical species richness of the studied group of insects and tried to calculate this ratio to other groups of plants and animals in order to provide a gross estimate of the total number of species on earth. Accordingly, Robert May explained that the total global species biodiversity is around 7 million.

Question 3.
Give three hypotheses for explaining why tropics show the greatest levels of species richness.
Answer:
In tropics:-

• No Catastrophes – In tropics, there have been no catastrophes but in temperate areas, glaciations and other catastrophes have caused large scale of destruction.
• Non-seasonal Environment – In tropics, seasons are nearly uniform. It promotes rich and increases species diversity.
• Solar Energy – Tropics get lots of sunlight which enhances productivity.

Question 4.
What is the significance of the slope of regression in a species-area relationship?
Answer:
According to German naturalist and geographer Alexander von Humboldt, species richness increased with increasing explored areas. The relationship between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola. It can be expressed with the help of an equation
log S = log C + Z log A, where
S = Species richness, A= Area,
Z = Slope of the line (regression coefficient),
C = Y-intercept
Ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2 regardless of the taxonomic group or the region.
(Whether it is the plants in Britain, birds in California, or mollusks in New York, the slopes of the regression line are amazingly similar). But the species-area relationship in very large areas, the slope of the line is much steeper (Z values in the range of 0. 6 to 1.2).

The importance of species Diversity to the Ecosystem:
Ecologists believed that communities with more species tend to be more stable than those with fewer species. A community which should not show too much variation in productivity from year to year is called a stable community. It must be resistant to occasional disturbances (natural or man-made) and resistant to invasion by alien species. David Tilman, the famous ecologist after conducting some long-term experiments using outdoor plots, explained that increased diversity contributed to higher productivity.

The rich diversity and higher productivity are not only essential for a healthy ecosystem but also imperative for the survival of the human race. At a time when we are losing species at an alarming pace, one might ask – Does it really matter to us if a few species become extinct? Would the Western Ghats ecosystem be less functional if one of its tree frog species is lost forever? It is difficult to find out the answer.

But we can develop a proper perspective through the rivet popper hypothesis of Stanford ecologist Paul Ehrlich. In an airplane (ecosystem) all parts are joined together using thousands of rivets (species). If every passenger travelling in it starts popping a rivet to take home, initially it may not affect the functioning of the ecosystem. But gradually the ecosystem becomes weak over a period of time and finally, it will cause the loss of a few rivets.

Question 5.
What are the major causes of species losses in a geographical region?
Answer:
Habits loss, Hunting, Habitat fragmentation, Forest fires. Alien species, Co extinction, Pollutions/Disturbance, Intensive agriculture, etc.

i. Habitat loss and fragmentation
This is the primary reason for biodiversity loss. It is due to cutting down trees, ploughing a grassland, filling a wetland, or burning a forest. The most dramatic example of habitat loss comes from the tropical rainforest. Once the forest-covered 1.4% of the earth’s land. Now it covers only 6%. The Amazon rain forest, the lungs of the planet, harbouring millions of species is being cut for cultivating soya beans or for conversion to grasslands for raising beef cattle. The fragmentation of forest i.e., broken up into small fragments due to human activities also lead to the disappearance of many species.

ii. Overexploitation
Biodiversity satisfies all human needs. But when the need turns to greed, it leads to the overexploitation of nature and natural resources. The extinction of Steller’s sea cow and passenger pigeon was due to over-exploitation by humans.

iii. Alien species invasions
New species entering a geographical region are known as exotic or alien species. The introduction of alien species into a new habitat by man may adversely affect the indigenous (native) species. Sometimes it will cause the extinction of native species. For example, the Nile perch introduced into Lake Victoria in east Africa led to the extinction of 200 species of cichlid fish in the lake. Carrot grass (Parthenium), Lantana, and water hyacinth (Eicchomia) are also alien invasive species that destroyed the environment. The introduction of African catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous catfishes. Another example is the introduction of the American cockroach, Periplaneta americana into India with food ships that has replaced the native cockroach Blatta orientalis.

iv. Co-extinctions
When a species becomes extinct, the animal or plant associated with it also becomes extinct. For example, the extinction of a host fish leads to the extinction of parasites associated with it.
Overexploitation, deforestation, noise pollution due to urbanisation, natural calamities like floods, droughts, fires, epidemic etc., use of wide range of animal and plant products for pharmaceuticals, cosmetics, perfumes, and aphrodisiacs, etc. also cause a threat to biodiversity.

Question 6.
How is biodiversity important for ecosystem functioning?
Answer:
i. Narrowly utilitarian: This argument for conserving biodiversity are obvious i.e., humans derive countless economic benefits such as food, firewood, fibre, construction materials, industrial products (such as tannins, dyes, lubricant, resins, perfumes etc.), medicinal products etc. More than 25% of medicines are derived from plants and nearly 25,000 species of plants contribute to the traditional medicines used by the native peoples around the world. It is unknown that how many medicinal plants are waiting to be explored in the tropical rain forest.

Broadly utilitarian: This argument says that biodiversity plays a vital role in all ecosystem services. Amazon rain forest alone produces 20% of the total oxygen in the atmosphere through photosynthesis. Can you estimate the economic value of this life-saving gas provided by nature? The other indirect benefits that we receive are

a. Pollination: Without pollination, the plants cannot give us fruits and seeds. The pollination is done by bees, birds, bats, etc.

b. Aesthetic and cultural benefits: The aesthetic values include ecotourism, bird watching, wildlife, pet-keeping, gardening, etc. Plants like Tulsi (Ocimum sanctum), Pipal (Ficus religiosa), etc. are considered sacred and are used by many Indians for religious purposes. Nowadays we recognize plants and animals as symbols of national pride and cultural heritage. Walking through a forest, watching spring flowers in full bloom, or waking up to a bulbul’s song in the morning, etc. also give pleasure and smoothness.

iii. Ethical argument: This says that we have a moral responsibility to take care of earth’s biodiversity such as millions of plants, animals, microbes, etc. with whom we share this planet. We need to realize philosophically or spiritually that each and every species on the earth has its own intrinsic value.

Question 7.
What are sacred groves? What is their role in conservation?
Answer:

• Sacred groves are places of worship where their exploitation or destruction is not allowed by worshipers.
  eg: Kumaon areas, Khasi Hills (Meghalaya), Aravalli hills (Rajasthan), Western Ghats (Kerala, Karnataka).
• They are the last refuge for a large number of rare and threatened plants and species only because of their freedom from exploitation.

Question 8.
Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
Answer:
The basic methods of flood control have been practiced since ancient times. These methods include reforestation and the construction of levees, dams, reservoirs, and floodways (artificial channels that divert floodwater). Soil erosion is controlled by mulching (bare soil between growing plants is covered with a layer of organic matter such as straw, grasses, leaves, husks etc.), cover rops and green manures, mixed cropping (growing a variety of crops), early planting (the period at beginning of the rainy season when the soil is prepared for planting), crop residues (after harvest leave the stalks, stems and leaves of the crop), agroforestry (planting trees among the agricultural crops), minimum cultivation, etc. can reduce soil erosion.

Question 9.
The species diversity of plants (22 percent) is much less than that of animals (72 percent). What could be the explanations for how animals achieved greater diversification?
Answer:

• Plants are fixed and need fewer adaptations and little competition to obtain optimum raw materials and sunlight. So little diversity.
• But in Animals, they are mobile, they converge on a single piece of vegetation, so comes competition that leads to species variation so has more diversity in animals.

Question 10.
Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
Answer:
If a particular species is extinct due to any activity, it will affect the existence of other related plants and animals. For eg. the relationship between the Calvaria tree and Dodo.

GSEB Class 12 Biology Biodiversity and Conservation Additional Important Questions and Answers

Question 1.
Complete the following, the name of scientists and their area in biodiversity conservation is given.

a. ……..(a)………….	: Biodiversity
b. Robert May	: ……..(b)………
c. ……….(c)…………..	: Species richness
d. Paul Ehrlich	: ………..(d)………..

Answer:
a. Edward Wilson
b. Global species diversity
c. Alaxander von Humboldt
d. Rivet popper hypothesis

Question 2.
A graph on species richness is given below. Complete the equations (a) and (b) according to Alexander von Humboldt.
Answer:
a. Log S = log C + Z log A
b. S = CA^Z
S – Species richness, A – Area, Z – Slope of the line (regression coefficient), C = Y-intercept

Question 3.
The table shows the number of species of birds seen in some places.
Colombia – 1400
New York – 105
Greenland – 56
India – 1200
South America (Amazon) – 1300
What could be the reason for the difference in the number of bird species present? Justify your answer.
Answer:
The species diversity decreases as we move away from the equator to the polar region. A latitudinal range of 23.5°N to 23.5°S has more species when compared to the temperate or polar regions. As in the table, Colombia, India, and Amazon areas are seen in the trophical region. So they have more species. New York and Greenland are seen in 41°N and 71°N latitude respectively. So we can see a decrease in the number of species. This may be due to the availability of more solar energy in the trophical regions.

Question 4.
In India, we have our own species of cockroach Blatta orientalis. But now we can see only American species Periplaneta americana.
a. What is the reason for this condition?
b. Give another example for the same condition.
c. Mention other causes for biodiversity losses.
Answer:
a. This is due to the exotic(alien) species introduction.
b. Nile perch introduced in lake Victoria of East Africa led to the extinction of about 200 species of cichlid fish.
c.

• Habitat loss and fragmentation
• Overexploitation
• Co-extinctions.

Question 5.
Amazon rain forest has the greatest biodiversity on earth. List any two hypotheses that are proposed by the biologists to account for the greater biological diversity.
Answer:
In tropics:

• No Catastrophes – In the tropics, there have been no catastrophes but in temperate areas glaciations and other catastrophes have caused a large scale of destruction.
• Non-seasonal Environment – In the tropics, seasons are nearly uniform. It promotes rich and increases species diversity.
• Solar Energy – Tropics get lots of sunlight which enhances productivity.

Question 6.
Recently a country held its cabinet meeting under the sea.
a. Name the country.
b. Why was it done?
Answer:
a. Maldives in the Indian ocean.
b. To get the world’s attraction to global warming and the increase of water levels in oceans

Question 7.
What’s species diversity?
Answer:
The variety of species within a given region is called species diversity.

Question 8.
Suppose you are the Secretary of your school Science Club and you are invited by the local body member to give a talk on “biodiversity” for the literacy mission. Prepare a note to be presented.
Hints: Importance of wildlife, conservation, damages.
Answer:
The term ‘wildlife’ has been defined by various naturalists and biologists. Wildlife refers to living organisms – plants, animals, and microorganisms other than the cultivated plants and domesticated animals. In Webster’s Dictionary “Wildlife is defined as living things that are neither human nor domesticated especially mammals, birds and fishes hunted by man”.

Importance of wildlife:
Wildlife has great importance to mankind due to its many values.

• Ecological value: Destruction of wildlife may upset the ecological balance in nature.
• Commercial value: Fur-bearing animals, the ivory of elephants, horns of rhinoceros, musk deer glands, etc. have high international value.
• Game value: Has great game value.
• Scientific value: Wildlife acts as a source of gene pool or gene bank for breeding programmes in agriculture, animal husbandry, fisheries, etc.
• Aesthetic value: Due to their beauty and appeal to humans they have high aesthetic value.
• Medicinal value: A large number of drugs are obtained from wild plants and animals which cure human suffering.

Question 9.
What are National Parks? Explain any five National Parks found in India.
Answer:
A national park is an area which is strictly reserved for the betterment of the wildlife and where activities like forestry, grazing or cultivation are not permitted.
Five national parks of India are:

1. Shivpuri park: It is located at Shivpuri near Gwalior (Madhya Pradesh). Wildlife present in this park tiger, cheetah, sambhar.
2. Gundi deer park: It is located near Chennai (Madras) in Tamil Nadu. Wildlife found here are Alvino deer, blackbuck, cheetah, and famous snake park.
3. Betia national park: It is located in Palamu at Bihar. Wildlife found in this national park is an elephant, tiger.
4. Dachigham national park: It is located in Srinagar in Jammu and Kashmir. Wildlife leopard, black beer, brown bear, musk deer, hangul, scrow, etc.
5. Bandhavgarh national park: It is located at Shahdol in Madhya Pradesh. Wildlife such as white tiger, panther, cheetah, bison, nilgai, barking deer, wild boar, etc. is found here.

Question 10.
The graph shown below indicates the per head consumption of energy. If it is going on in this manner, there will be an energy crisis in the nearby future. To suggest an alternate way to face this situation.

Answer:

• Limited use of fossil fuels.
• Use of smokeless and efficient wood stoves.
• The exploitation of solar energy.
• Use of biogas plants.
• Generation of hydroelectricity from wind and tidal power.
• Growing fuelwood trees and shrubs.

Question 11.
The Periyar Wildlife Sanctuary is the pride of Kerala.

1. Where is this sanctuary located in Kerala?
2. Give the importance of this place.

Answer:

1. Thekkady (Idukki district)
2. Protection is given to the animals such as tigers, elephants.

Question 12.
The following figure is of an eminent environmentalist.

a. Name the personality.
b. Mention his contribution in this regard.
c. To which state does he belong?
Answer:
a. Sundarlal Bahuguna
b. He is the leader of the ‘Chipko Movement’. He coined the Chipko slogan ‘ecology is the permanent economy’.
c. Uttarakhand

Question 13.
There is a type of conservation of genetic resources through their maintenance within the natural or man-made ecosystems.
a. Which type of conservation is this?
b. Give the importance of the protected areas and the divisions involved in this.
Answer:
a. In-situ conservation
b. The areas of land or sea which are meant for the protection and maintenance of biodiversity, natural resources etc. Divisions – National parks, Sanctuaries, Biosphere reserves, Cultural landscapes, Natural monuments etc.

Question 14.
Even though Kerala is a small state, she has two National Parks, three Wildlife Sanctuaries and two Biosphere Reserves.
a. Prepare a radio talk on ‘the conservation of nature’ giving emphasis to Kerala and the animals to be protected there.
Answer:
Refer to the answer of Qn.No.1 + Mention the definition and significance of National park. Wildlife sanctuaries and Biosphere reserves.

Question 15.
We heard of the slogans “we two have two” and “one family one tree”. Give the importance of these slogans according to your views.
Answer:
“We two have two”
In 1947, at the time of partition, the population of India, Pakistan and Sri Lanka was 53 crore. At present, the population of India alone is 105 crore. If the present growth continues, in the very near future man will face scarcity for food, housing, drinking water and other basic necessities. So we must follow the government policy \ve two have two’.

China has passed a strict law that there will be one child from one couple. Anybody having a second child pays tax to the government for 18 years. Is it not possible that this law is to be passed in India also?

One family one tree

The target for 2007 is atleast 100 million trees. The ultimate aim is to create awareness and develop public knowledge and involvement. So 100 million trees are planted every year.

Question 16.
Select the correct statements from the following

• IUCN red list is a catalogue of animals facing risk of extinction
• 3rd October is observed as World Animal Day.
• Eravikulam National Park is in Karnataka.
• Morphine is extracted from Papaver somniferum.

Answer:

• IUCN red list is a catalogue of animals facing risk of extinction
• 3rd October is observed as World Animal Day.
• Morphine is extracted from Papaver somniferum.

Question 17.
Based on this picture given below, prepare a short note on Eravikulam National Park.

Answer:
Eravikulam National Park :
Originally established to protect the Nilgiri Tahr, the Eravikulam Park is situated in Devikulam taluk of the Idukki district. It was declared as a sanctuary in 1975, and considering its ecological, faunal, floral, geo-morphological and zoological significance, it was declared as a National Park in 1978. It covers an area of 97 sq.kms of rolling grasslands and high level sholas. The park is breathtakingly beautiful and is comparable to the best of mountain ranges in the Alps.

Tiger, panther and wild dogs are usually sighted in both the open grassland and shola forests. Civet cat and jungle cat also live in the sholas. Sloth bear, Nilgiri langur and wild boar are generally found in sholas and their fringes. The Atlas moth, the largest of its kind in the world, is seen in this park. The population of the world famous Nilgiri Tahr is 1317 according to the 1991 census. There were only 885 in 1989.

Question 18.
There is shift in the policy of animal collection in the zoo from ‘unlimited animals and limited facilities’ to ‘limited animals and adequate facili¬ties’. Give reason.
Answer:
Zoos were considered as picnic spots in the past. Now, they are managed as conservation and education centres where captive breeding of rare and endangered animals is undertaken and more and more information on wildlife conservation and management is generated through scientific research. Accordingly, there is a shift in the policy of animal collection in the zoo from ‘unlimited animals and limited facilities’ to ‘limited animals and adequate facilities’.

Question 19.
Suggest a proper title for a poster that you have prepared as a part of Wildlife Week Celebrations related with ‘tiger conservation’.
Answer:
‘Tiger is our national pride Let them live freely’

Question 20.
Who proposed the rivet popper hypothesis? Explain the same with reference to the ecosystem.
Answer:
This hypothesis was proposed by Paul Ehrlich.

• In airplanes (ecosystems), all parts are joined together by using thousands of rivets (species).
• If every passenger travelling in this ecosystem causes the extinction of atleast one species (starts popping a rivet to take home), it may not be safer but if more and more rivets are removed, the plane becomes dangerously weak over a period of time.
• Further which rivet is removed may also be critical, loss of those on the wings is obviously a series threat to flight safety than those of a few on the seats or windows.
• Similarly, the loss of key species, which run the ecosystem properly, is obviously a more serious threat to the ecosystem than other species.

Question 21.
The prosperity of human beings in the whole world lies in the prosperity of nature. Justify this statement.
Answer:
The prosperity of human beings in the whole world lies in the prosperity of nature. The depletion of land resources due to soil erosion, salination, acidification, alkalinization, waterlogging, construction of roads, railways and dams, urbanization, industrialization, mining activities, etc. will alter the ecosystem which in turn affects the plants which form the basic producers and provide food to the whole living world. Plant resources are renewable but are depleting due to deforestation, overgrazing, forest fires, environmental pollution, etc. So care must be taken to preserve the ecosystem.

Question 22.
The fragmentation of a forest and deforestation lead to the disappearance of species and drastic climatic variation.
a. Give some adverse effects of indiscriminate cutting down of forests.
b. Suggest some measures to check deforestation.
Answer:
The indiscriminate cutting down of forest is also known as deforestation. Due to deforestation, the main problem is soil erosion. The raindrops directly fall on the ground causing soil erosion. The soil will be carried to the river and gets deposited in the river bed. The forests are also having a significant role in climatic regulation. The measures for checking deforestation can be only done by public awareness and strict legislation.

Question 23.
Give differences between National Park, Sanctuary and Biosphere Reserves.
Answer:
Biosphere Reserves: These are protected areas of land or coastal envi­ronments to conserve the ecosystem and the genetic resources con­tained therein. The concept of Biosphere Reserve was launched by UNESCO in 1975 under its Man and Biosphere Programme. India has 14 Biosphere Reserves.

National Parks: A National Park is an area which is strictly reserved for the welfare of the wildlife where activities such as cultivation, grazing etc. are strictly prohibited. Private ownership rights and habitat manipu­lation are also not permitted there. India has 90 National Parks.

Wildlife Sanctuaries: The area in which protection is given only to ani­mals is called sanctuary. Operations such as collection of timber, minor forest products and private ownership rights are allowed so long as they do not interfere with the well being of animals. India has 448 wildlife sanctuaries.

Question 24.
In 1992 the Earth Summit was held at Rio de Janeiro to conserve biodiversity. Give the objectives attained by that Summit.
Answer:
The objectives attained in the Earth Summit held at Rio de Janeiro in 1992 are

• conservation of biodiversity
• sustainable use of biodiversity
• sharing of benefits arising out of the utilization of genetic resources.

Question 25.
Mention the different wildlife organisations.
Answer:
The Nature Conservancy

The Nature Conservancy works with local communities, businesses, and individuals to protect over 100 million acres of land around the globe. The goal of this organization is to preserve entire wildlife communities along with their rich species diversity, a holistic approach that’s vital to the health of our planet.

The World Wildlife Fund

The World Wildlife Fund works with multilateral and bilateral agencies to promote sustainable development in the world’s poorest countries. Its aims are threefold — to protect natural ecosystems and wild populations, to minimize pollution, and to promote efficient, sustainable use of natural resources.

The Natuaral Resouses Defense Council

The Natural Resources Defense Council is an environmental action organization consisting of over 300 lawyers, scientists, and other professionals that commands a membership of about 1.3 million people worldwide.

The Sierra Club :

The Sierra Club, a grassroots organization that works to protect ecological communities, encourage smart energy solutions, and create an enduring legacy for America’s wildernesses, was founded by naturalist John Muir in 1892.

Question 26.
Silent Valley is a National Reserve Forest in Kerala. Why is it called so?
Answer:
Because of the absence of Cicada

Question 27.
Write an explanatory note on the efforts for the conservation of biodiversity in India.
Answer:
I. In-situ conservation: The conservation of genetic resources through their maintenance within natural or even human-made ecosystem in which they occur, is called in-situ conservation. In-situ includes protection of a group of typical ecosystem through a network of protected areas. The areas of land or sea which are meant for the protection and maintenance of biodiversity are called protected areas, e.g. National parks, sanctuaries, biosphere reserves, cultural landscapes, natural monuments, hot spots, sacred groves etc.

Hot spot: Eminent conservationists identified certain regions with very high levels of species richness and high degree of endemism (the species that is confined to that region and not found anywhere else) to protect biodiversity. Hot spots are the richest and the most threatened reservoirs of plant and animal life on earth. The concept of hot spot was developed in 1988 by Norman Myers to designate the priority areas for in-situ conservation. Initially 25 biodiversity hot spots were identified but subsequently nine more have been added to the list. Now the number of hot spots in the world is 34. Three of these hot spots – Western Ghats and Sri Lanka, Indo-Burma and Himalaya cover our country’s high biodiversity regions. Eventhough hot spots cover less than 2% of the earth’s land area, they accommodate extremely high number of species. They also reduce the ongoing mass extinction by almost 30%.

Biosphere Reserves: These are protected areas of land or coastal environments to conserve the ecosystem and the genetic resources contained therein. The concept of Biosphere Reserve was launched by UNESCO in 1975 under its Man and Biosphere Programme. India has 14 Biosphere Reserves.

National Parks: A National Park is an area which is strictly reserved for the welfare of the wildlife where activities such as cultivation, grazing etc. are strictly prohibited. Private ownership rights and habitat manipulation are also not permitted there. India has 90 National Parks.

Wildlife Sanctuaries: The area in which protection is given only to animals is called sanctuary. Operations such as collection of timber, minor forest products and private ownership rights are allowed so long as they do not interfere with the well being of animals. India has 448 wildlife sanctuaries.

Sacred groves (forest): These are forest patches protected by several tribal communities and religious groups due to religious sanctity to forest. In Kerala it is called sacred groves. The sacred groves are found in Khasi and Jaintia Hills in Meghalaya, Aravalli hills of Rajasthan, Western Ghat regions of Karnataka and Maharashtra and the Sarguja, Chanda and Bastar areas of Madhya Pradesh. In Meghalaya the sacred groves are the last refuges for a large number of threatened species.

II. Ex-situ Conservation: The conservation outside their habitats by perpetuating sample population in genetic resource centres, zoos, botanical gardens, wildlife safari parks, gene banks etc. is known as ex-situ conservation. There are many animals that have become extinct in the wild but continue to be maintained in the zoological parks.
Cryopreservation is one of the ex-situ conservation methods. The storage of materials at very low temperature either by rapid cooling (for seeds) or by gradual cooling and simultaneous dehydration at low temperature (for tissue culture) is known as cryopreservation. It is done in liquid nitrogen at a temperature of – 196°C. Gametes of threatened species can be preserved in viable and fertile form by this method.

Conservation of biodiversity by botanical garden is very important. There are about 1500 botanical gardens in the world conserving about 80,000 species. Nearly about 3000 species of mammals, birds, reptiles and amphibians are conserved in professionally managed zoos. Gene banks preserve valuable plant materials which are likely to become extinct.

Conservation of biodiversity is the collective responsibility irrespective of the political boundaries. The historic convention on Biological Diversity (The Earth Summit) held in Rio de Janeiro in 1992, called upon all nations to take necessary steps for conservation of biodiversity. The World Summit on Sustainable Development held in 2002 in Johannesburg (South Africa) 190 countries took pledge that we achieve a significant reduction in biodiversity loss by 2010.

Question 28.
Briefly explain.
a. Ex situ conservation
b. In situ conservation
c. Protected areas
d. Biosphere Reserves
e. Red list
Answer:
a. Conservation outside the habitats
b. Conservation inside natural habitats.
c. The areas of land or sea which are meant for the protection and maintenance of biodiversity, natural resources etc.
d. The protected areas of land or coastal environments to conserve the ecosystem and the genetic resources present there are known as biosphere reserves.
e. Red list is a catalogue of taxa that are facing the risk of extinction.

Question 29.
Our wildlife resources are depleting very fast. Suggest possible measures to check the same.
Answer:
The possible measures to check the wildlife resources are

• Strict legal measures must be given to the poachers.
• Public must be made aware about the depleting wildlife resource.
• By protecting the ecosystem like Biosphere reserves, National parks, Sanctuaries etc.

Question 30.
What was the purpose of establishing Jim Corbett National Park?
Answer:
To conserve Tiger, Panther, Elephant

Question 31.
Name the National Parks famous for
a. Tiger
b. One horned Rhinoceros
c. Lion tailed monkey
d. Nilgiri Tahr
e. Asiatic lion
Answer:

a. Tiger	Corbett National Park
b. One horned Rhinoceros	Kaziranga National Park
c. Lion tailed monkey	Silent Valley National Park
d. Nilgiri Tahr	Eravikulam National Park
e. Asiatic lion	Gir National Park

Question 32.

a. Observe the board and write your opinion.
b. Give the scientific name of the animal.
c. Wildlife is our treasure. Give reason.
Answer:
a. The figure on the board is Nilgiri Langur. It is a primate facing extinction. It is found in Silent Valley National Park. Many of the tribes and other local people believed that the flesh of Nilgiri langur (black langur) is good for health and curing certain diseases. They prepare a Rasayanam using the flesh of this animal. Actually its flesh has no medicinal value. So let them be undisturbed.

b. Samnopithecus johnii (previously known as Presbytis johnii)

c. Wildlife is our treasure because wildlife has great importance to mankind due to its many values.

• Ecological value: Destruction of wildlife may upset the ecological balance in the nature.
• Commercial value: Forbearing animals, ivory of elephants, horns of rhinoceros, musk deer glands etc. have high international value.
• Game value: Great game value.
• Scientific value: Wildlife acts as a source of gene pool or gene bank for breeding programmes in agriculture, animal husbandry and fisheries etc.
• Aesthetic value: Due to their beauty and appeal to humans they have high aesthetic value.
• Medicinal value: A large number of drugs are obtained from wild plants and animals which cure human sufferings.

Question 33.

The board you see is placed in front of a National Park. Evaluate the quotation on the board and state your opinion, keeping in mind the need for Biodiversity and Conservation.
Answer:
The board signifies us that

• Do not approach or disturb any wildlife you may encounter.
• Do not feed the wildlife or remove any wildlife from the Arboretum.
• Do not release wildlife at the Arboretum.
• Do not pick flowers, fruits, vegetables or seeds.
• Do not stand or walk in the garden beds.
• Do not litter.
• Do not tease the wildlife.
• Enjoy the wildlife and let them live undisturbed in their natural habitat.
• Wildlife is our treasure. So conserve it properly.

Question 34.
Imagine that one day the water on the whole earth disappeared. Give some consequences that we would face.
Answer:
Water scarcity is a serious problem and one that already affects a great deal of the earth’s population. The UN considers water scarcity as such a significant issue that it made “coping with water scarcity” its theme for World Water Day 2007. During the World Water Day celebration in Rome on March 22, the Director General of the UN’s Food and Agricultural Organization called water scarcity the challenge of the 21st century. The WHO states that water scarcity currently impacts four out of every ten people in the world, and it projects that nearly 2 billion people will be living in countries or regions with absolute water shortage by the year 2025.

Lack of water to meet daily needs is a reality for many people around the world and has serious health consequences. Globally, water scarcity already affects four out of every ten people. The situation is getting worse due to population growth, urbanisation and increased domestic and industrial water use. This fact file highlights the health consequences of water scarcity such as diarrhoeal diseases including cholera, typhoid fever, dysentery etc.

Question 35.
The identified species of all organisms on the earth range between 1.7 to 1.8 million. Global Biodiversity Information Facility and the Species 2000 have identified the number of species in each group of animals.
a. Name the group with maximum species identified.
b. Name the group with the less species identified.
c. Give an approximate number of mammalian species identified.
Answer:
a. Insects
b. Viruses
c. 4,650

Question 36.
Observe the following pie diagram and make a write up on the percentage of the threatened species in Amphibia, Birds and Mammals.

Answer:
According to IUCN Red List, there are 5,485 animal species and 5,611 plant species listed as threatened. Of these, 1939 are placed under critically endangered. According to the List, in India 18 animal species are critically endangered, 54 are endangered and 143 are vulnerable. Amongst plants, 44 species are critically endangered, 113 are endan­gered and 87 are vulnerable.

Question 37.
One of the major reasons for extinction of species is the destruction of habitat. Justify this statement by using two examples from your surroundings.
Answer:
Any two particular species – their habitat and how they are destroyed.
Eg : Extinction of Rana hexadactyla
Due to the destruction of marshes.

Question 38.
The given bar diagram shows the population size of Rana hexadactyla in the rice fields of Malabar. Observe and analyse the graph.

a. Write your findings from the graph
b. Predict the population of frogs in the near future
c. Enlist the reasons for this effect
Answer:
a. The number of frogs decreases
b. Extinction
c.

• Habitat destruction
• Excess use of pesticides
• Change in climate
• Use of agricultural machines
• Excessive killing

Question 1
In the Pie charts (a) and (b) drawn below to show the global animal diversity, which groups of animals would you name and write on the areas shaded black in (a) and (b). In which kind of habitat would you find these groups of animals?

a. Invertebrates b. Vertebrates
Answer:
a. Invertebrates Shaded area – Insects
Habitat – Aerial, terrestrial and aquatic
b. Vertebrates Shaded area – Fishes Habitat – Aquatic

Question 2.
Amazonian rain forests have the greatest biodiversity on earth. List any two hypotheses that are proposed by the biologists to account for the greater biological diversity.
Answer:

• The Amazonian forests, called as the Lungs of Planet Earth with constant environments promote niche specialisation and lead to a greater species diversity.
• Amazonian forests have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.