Biodevrsity and Conservation

7/30/2019 Biodevrsity and Conservation

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BIODEVRSITY AND CONSERVATION

The term biodiversity means the sum total of diversity that exists at all levels of biologicalorganization.

The term biodiversity is popularized by the sociobiologist, Edward Wilson. Explain the three important components of biodiversity with examples ?

Genetic diversity, species diversity and ecological diversity are the three important componentsof biodiversity1. Genetic diversity The variation of genes within the species is known as genetic diversity.

Examplesa) The medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges

produce different varieties of active chemical reserpine. b) India has more than 50,000 genetically different strains of rice and 1000 varieties of

mango. 2. Species diversity

The occurrence of different verity of species within a region is called species diversity.

Example ;-The Western Ghats have greater number of amphibian species than Eastern Ghats.

3. Ecological diversity Diversity at the level of community and ecosystem is known as ecological diversity.

Example ;-India has greater ecosystem diversity in deserts, rain forests, mangroves, coral reefs, wet

lands, estuaries and alpine meadows than the country like Norway. How do ecologists estimate the total number of the species present in the world?

It is difficult to answer that how many species are there on the earth. According to IUCN the total number of animals 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. Biologists often make statistical comparison of the temperate tropical species richness of the

studied group of insects and tried to calculate this ratio to other group of plants and animalsinorder to provide gross estimate of the total number of species on earth.

According to Robert May, total global species biodiversity is around 7 million. The figure given below represents the global biodiversity of major taxa of invertebrates,vertebrates and plants. Study the figure and list out your conclusions.?


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Answer More than 70% of all the species recorded are animals. Plants include up to 22% of the total. Among animals, insects are the most species rich taxonomic group, making up more than 70%

of the total. That is out of 10 animals on the planet 7 are insects. Among vertebrates, fishes constitute the largest diversity group. Among plants, fungi and angiosperms are the largest diversity group. In the plant kingdom, the fungi species is more than the combined total species of the

amphibians, reptiles and mammals.Comment on the biodiversity of India? India is one of the 12 mega diversity countries of the world. India shares about 8.1% of the global species diversity even though India has only 2.4% of the

worlds land area. Nearly 45,000 species of plants and twice the number of animals have been recorded in India. According to Robert Mays global estimates, in India only 22% of the total species have been

recorded so far. As per the above estimate, there are 100,000 species of plants and 300,000 species of animals

yet to be discovered and described.

PATTERNS OF BIODIVERSITYTwo patterns of biodiversity are presentI. Lattitudinal gradients

II. Species area relationship Explain latitudinal gradient in biodiversity?

The diversity of plants and animals is not uniform throughout the world but shows a ratheruneven distribution.

The most well known gradient in diversity is latitudinal gradient. In general, species diversity decreases as we move away from the equator towards the poles. With very few exceptions, tropics (latitudinal range of 23.5 0 N to 23.5 0 S) harbor more species

than temperate or polar areas.The tropical region of earth is rich in species diversity than temperate or polar regions. Explainthis statement with examples? Colombia, located near the equator has nearly 1400 species of birds while New York at 41 0 N

has 105 species and Green land at 71 0 N has only 56 species. India, with much of its land area in the tropical region has more than 1200 species of birds. The tropical Amazonian rain forest in South America has the greatest biodiversity on earth. It is

home to more than 40,000 species of plants, 3,000 species of fishes, 1,300 species of birds, 427species of mammals, 427 species of amphibians, 378 species of reptiles and more than 1,25,000species of invertebrates.

What are the reasons for great species diversity or species richness in the tropical regions? Tropical regions have remained relatively undisturbed for millions of years and thus had a

long time for species diversification. Tropical environments are less seasonal, relatively more constant and predictable. Availability of more solar energy in this region contributes much productivity.

Explain species area relationship in biodiversity? The great German Naturalist and Geographer Alexander Von Humboldt observed that within

a region species richness increased with increasing explored area, but only up to a limit.


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The relation between species richness and area for a wide variety of taxa such as angiospermplants, birds, bats, freshwater etc turns out to be a rectangular hyperbola.

On a logarithmic scale, the relationship is a straight line described by the equation,Log S = log C + Z log A

Where, S = species richnessC = Y interceptZ = slope of the line (regression coefficient)A = Area

What is the significance of the slope of regression coefficient in a species area relationship? 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. But, if we analyse the species area relationship among very large areas like the entire

continents, we will find the slope of the line to be much steeper; that is Z values in the range of0.6 to 1.2.

For example, for frugivorous (fruit eating) birds and mammals in the tropical forest of differentcontinents, the slope is found to be 1.15.

Rich biodiversity is not only essential for the ecosystem health but important for the verysurvival of the human raceon this planet. Explain this statement on the basis of Rivet poper hypotheses? Survival of each and every species on this earth is important for the survival of the other

species. One might think, what will happen if one species of tree frog of Western Ghats become extinct?

The answer for this question can be well explained with Rivet poper hypotheses of Stanfordecologist Paul Ehrlich.

Ehrlich, compared ecosystem to an aeroplane. In an aeroplane all parts are joined together using thousands of rivets. The rivets are compared to species of the ecosystem. If every passenger travelling in it starts to popping a rivet to take home (causing a species to

become extinct) it may not affect flight safety initially (proper functioning of the ecosystem) As more and more rivets are removed, the plane become dangerously weak over a period of

time.


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Furthermore, which rivet is removed may also be critical. Loss of rivets on the wings (keyspecies that drives major ecosystem function) is obviously a more serious threat to flight safetythan loss of a few rivets on the seats or windows inside the plane.

LOSS OF BIODIVERSITY The biological wealth of our planet has been declining rapidly and the accusing finger is clearly pointing to human activities. How far this statement is true?. Explain your answer with the present situation of loss of biodiversity.

The accelerated rates of species extinction that the world is facing now are greatly due tohuman activities.

The colonization of tropical Pacific Islands led to the extinction of more than 2,000 species ofnative birds.

As per IUCN Red list, 784 species extinct in the last 500 years. This include 338 vertebrates, 359invertebrates and 87 plants.

Some examples of recent extinctions include the dodo (Mauritius), quagga (Africa) , thylacine(Ausralia), Styellers sea cow (Russia) and 3 sub species of tiger (Bali, Javan, Caspian).

Currently, 15,500 species world wide are facing the threat of extinction. Presently 12% of all bird species, 32% of all amphibian species, 23% of all mammal species and

31% of all gymnosperm species in the world face the threat of extinction. The current species extinction rates are estimated to be 100 to 1000 times faster than in the pre-human times and our activities are responsible for the faster rates.

Ecologist warns that if the present trends continue, nearly half of all the species on earth mightbe wiped out within the next 100 years.

What are the causes of biodiversity losses or species losses in a geographical region ? OR what are The Evil Quartletof biodiversity losses? The extinction species and consequent loss of biodiversity are due to mainly four major

reasons. They are known by the sobriquet The Evil Quartlet 1. Habitat loss and fragmentation

It is due to cutting down of trees, ploughing a grassland, filling a wetland or burning aforest.

The best example is the tropical rain forest. Once the forest covered the 14% of earthsland. Now it covers only 6%.

The Amazonian rain forest, the lungs of the planet, harboring millions of species is beingcut for cultivating soya beans or for conversion to grasslands for raising beef cattle.

The fragmentation of the forest i.e., broken down into small fragments due to humanactivities also led to the disappearance of many species.

2. Over exploitation Biodiversity satisfies all the human needs. But when need turns to greed, it leads to the

over exploitation of nature and natural resources. The extinction of Stellers sea cow and passenger pigeon were due to over exploitation by

humans.3. Alien species invasions

(Introduction of exotic species is one of the major threats to biodiversity. Substantiate?)

New species entering a geographical region are known as exotic or alien species. Introduction of alien species to a new habitat may adversely affect the native species.

Some time it may leads to the extinction of the species.


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For example, the Nile perch introduced into Lake Victoria in east Africa led to theextinction of 200 species cichlid fish in the lake.

Carrot grass (Parthenium), Lantana and water hyacinth ( eicchornia ) is also alien invasivespecies that destroyed the environment.

The introduction of African cat fish Clarias gariepinus for aquaculture purpose is posing athreat to the native cat fishes.

The introduction of American cockroach, Periplaneta americana into india with food

ships has replaced the native cockroach Blatta orientalis. 4. Co-extinctions When a species extinct, the animal or plant associated with it also extinct. This is known as

co-extinction. For example, the extinction of a host fish leads to the extinction of parasites associated

with it.Overexploitation, deforestation, noise pollution due to urbanization, natural

calamities like flood, droughts, fires, epidemic etc., use of wide range of animal and plantproducts for pharmaceuticals, cosmetics, perfumes etc. also cause threat to biodiversity.

BIODIVERSITY CONSERVATION

Why should we conserve biodiversity? OR How is biodiversity important for ecosystem functioning?The reasons for conserving biodiversity can be grouped into 3 categories.

1. Narrowly utilitarian2. Broadly utilitarian3. Ethical argument

1. Narrowly utilitarian This argument for conserving biodiversity is obvious; humans derive countless economic

benefits such as food, firewood, fibre, construction materials, industrial products (tannins,dyes, lubricant, resins, and perfumes) and medicinal products etc.

More than 25% of medicines are derived from plants and nearly 25,000 species of plantscontribute to the traditional medicines used by the native people around the world.

Nobody knows how many more medicinally useful plants there are in tropical rain forestswaiting to be explored.

2. 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.The other indirect benefits that we receive are,

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

b) Aesthetic and cultural benefits The aesthetic value includes ecotourism, bird watching, wildlife, pet keeping,

gardening etc. Walking through a forest, watching spring flowers in full bloom or walking up to a

bulbuls song in the morning etc. also give pleasure. 3. Ethical argument

This argument says that we have a moral responsibility to take care of earths biodiversitysuch as millions of plants, animals, microbes etc. with whom we share the planet.


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We need to realize the philosophically or spiritually that each and every species on the earthhas its own intrinsic value.

How do we conserve biodiversity? The ecosystem is changed by natural as well as man made disturbances. So it is very important

to take necessary steps to conserve biodiversity effectively and efficiently to prevent furtherdestruction or degradation of habitats.

It is our duty to look after our planet, protect it and pass it on to coming generation withoutany damage.Conservation of biodiversity can be done by two ways.

1. In situ conservation2. Ex situ conservation

1. 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 typical ecosystem through a network of protected

areas.

The areas of land or sea which are meant for the protection and maintenance of biodiversityare called protected areas. Examples for protected areas are National parks, sanctuaries, biosphere reserves, cultural

landscapes, natural monuments, hot spots, sacred groves etc. Hot spots Hot spots are the regions with very high levels of species richness and high degree of

endemism (that is, species confined to that region and not found anywhere else) Now there are 34 biodiversity hot spots in the world. Western Ghats and Sri Lanka, Indo-Burma and Himalaya- covers our countrys high

biodiversity regions. Eastern himalayas and Western Ghats are the hot spots of Kerala

Even though hot spots cover less than 2% of the total earths land area, they accommodateextremely 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 within the ecosystem. India has 14 Biosphere Reserves. Agasthyamalai and part of Nilgiris are the biosphere reserves in kerala.National parks A national park is an area which is strictly reserved for the welfare of the wild life where

activities such as cultivation, grazing etc. are strictly prohibited. India has 90 national parks. The first national park of india is Jim Corbet National Park Of Uttar Pradesh

Wild life sanctuaries The area in which protection is given only to animals is called sanctuary. India has 448 wildlife sanctuaries. Periyar sanctury in Kerala protects a wide range of wild life


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Sacred groves(What are sacred groves? What is their role in conservation?) These are forests protected by tribal communities, which are free from all disturbances.

Tribal give religious sanctity to the forest. The flora and fauna is well protected here. Cutting of trees is not done for commercial purposes. Sacred groves are the last refuges for a large number of rare and threatened species

E.g. ., forests of Karnataka, Maharashtra, Meghalaya and the traditional sarpakavu of Kerala2. Ex situ conservation

The conservation of organisms outside their habitats such as Zoos ,botanical gardens ,wildlifesafari parks,

Cryopreservation It is a method of ex situ conservation in which the gametes of threatened species are preserved

in viable and fertile condition for long periods using cryopreservation technique.(the storageof materials at very low temperature)

Eggs can be fertilized in vitro and plants can be propagated using tissue culture methods. Seeds of different genetic strains of commercially important plants can be kept for long

periods in seed banks.

The Earth Summit held in Rio de Janero in 1992 , called upon all nationsto take appropriate measures for conservation of biodiversity and sustainable utilization of itsbenefits. The World Summit On Sustainable Development held in 2002 in Johannesburg ,South Africa , 190 countries pledged their commitment to archive by 2010, a significant reductionin the current rate of biodiversity loss at global, regional and local levels.

Among the ecosystem services there are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?

The basic method of flood control includes reforestation, construction of dams, reservoirs,artificial channels which divert flood water etc.

Soil erosion is controlled by growing a variety of plants or grasses on the bare land, agroforestry (planting trees among the agricultural crops), minimum cultivation etc.

The species diversity of plants (22%) is much less than that of animals (72%). What could be theexplanations to how animals achieved greater diversification?

The great structural and resource heterogeneity provided by plants is the principal reason ofhigh animal diversity.

A single plant can accommodate many animal species.

Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

If a particular species is extinct due to any activity, it will affect the existence of other relatedplants and animals.

Example is the relationship between Calvaria tree and Dodo.


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As a biology student ,can you agree starting a multinational company in Eravikulam offering employment of 20000 people?

We can agree if the company will not alter the biodiversity of that area They should be eco friendly also There must be no pollution. Use only biodegradable substances

Our wild life resources are depleting very fast .Suggest possible measures to check the same?

1.

Strict legal measures must be given to the poachers. Aware about the depleting wildliferesources.2. By protecting the ecosystem like biosphere reserves, national parks, sanctuaries etc.

Biodiversity has some aesthetic and cultural values. Substantiate?

The aesthetic values include ecotourism, bird watching, wild life, pet keeping, gardeningetc.

Plants like tulsi ,peepal etc are considered as sacred and are used by many Indians forreligious purposes

Several birds and snakes are considered as sacred Naga temples are common in India. Today plants and animals are recognized as symbols of national pride and cultural heritage.

Biodiversity conservation in India is up to the mark Do you agree? In my view, it is not up to the mark. Because,1. We are not controlling pollution.2. Population growth may lead to shortage on land or habitation.3. Not giving awareness to people4. Laws are not strictly followed

Notes Prepared ByBiju T LHSST ZoologyGHSS Mylachal, Tvpm


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Biodevrsity and Conservation