BIODIVERSITYThe occurrence of different types of genes, gene pools, species, habitats and ecosystems in a particular place and various parts of earth is called

biodiversity. The term coined by WALKER .G.

ROSEN and popularized by EDWARD WILSON

Levels of diversity• 1.Genetic diversity.• 2.Species diversity.• 3.Ecological diversity.• 1.Genetic diversity.• It is a measure of variety in genetic

information contained in the organisms.• Greater the genetic diversity , More

sustenance against environment perturbations.

• Genetically uniform population are highly prone to diseases in harsh environment.

• Ex.Rauwolfia vomitoria shows variation in potency of chemical reserpine.

• In India more than50,000 genetically different strains of rice and 1000 varieties of mango.

• 2.Species diversity.• Species diversity is the variety of species and

their relative abundance present within a region.

• There are two important measures of species diversity.

• 1.Species richness. It is the number of species per unit area.

• 2.Species evenness-It is the relative abundance with which each species is represented in an area.

• The level of diversity of an ecosystem is determined by the variety and number of individuals.

• ex. there is a greater diversity of amphibians in Western Ghats than Eastern Ghats

• Ecological diversity. It is the diversity at community and ecosystem level.

• There is a greater ecosystem diversity in India• ex .Biomes like Alpine Meadows, Rain forests,

Deserts, Wetlands. Mangrove forests, Coral reefs.

GLOBAL DIVERSITY

• The total number of plants and animals described is about 1.5 million according to IUCN.2004

• Robert May has made more conservative scientifically sound estimate, which puts the global species diversity at about 7 million.

• Animals – more than 70 % .

The estimate do not give any figure for prokaryotes because….• 1.The conventional taxonomic methods are

not sufficient for identification of microbes• 2. Under laboratory conditions , many of the

species cannot be cultured.• Their diversity would be put into millions by

biochemical and molecular biology techniques.

INDIAN BIODIVERSITY.

• India is among the 12 mega diversity countries of the world.

• India has 8.1 % of Global species DIVERSITY though it has only 2.4% of the worlds land area.

• There are 90,000-1,00000 species of animals and about 45,000 species of plants, only 22% of the total species have been recorded.

• More than 1,00000 species of plants and more than 3,00000 species of animals to be discovered and described.

BIODIVERSITY PATTERNS

• Biodiversity varies with change in latitude and altitude

• Speciation is favoured by favourable environmental conditions.

• 1.Latitudinal and Altitudinal Gradients.• There is a decrease in species diversity from

equator towards poles.• The greatest biodiversity on earth is the

Amazonian rain forest in South America.

• There are three hypothesis tom explain the differences in biodiversity between tropical and temperate regions

• 1.In general, speciation is a function of time, as the temperate regions were subjected to frequent glaciations in the past, the tropics have remained undisturbed and thus more species diversity.

• 2.Tropical environment are less seasonal,so relatively more constant and predictable than temperate regions. such constant environments have promoted niche specialization and greater species diversity.

• 3.The availability of solar radiation,is more in tropical region which contribute directly to more productivity and indirectly to greater species diversity.

• 2. Species Area relationship.• It was observed by Alexander Van Humboldt

that within a region species richness increases with increased explored area but only up to a limit.

• For a number of taxa like angiosperms, fresh water fishes and birds the relatioship between species richness and area is found to be a rectangular hyperbola

Alexander Van Humboldt

• The relationship becomes linear(straight line ) on a log scale and is described by the equation.

logS=logC+Z log A.Where S= Species Richness. Z= Slope of line ( regression coefficient) A=Area and C=Y-intercept. Ecologists have found that irrespective of the

taxonomic group or region, the value o if Z –Line ranges between 0.1 and 0.2.

But the z-value ranges between 0.6 and 1.2 in very large area, like a continent.

The z value is 1.15 for the frugivorous and mammals in the tropical forests

Importance of biodiversity to ecosystem

• A stable community has the following attributes.

• 1.There should not be much variations in the year to year productivity.

• 2.It should be either resistant or resilient to seasonal disturbance.

• 3. It should be also resistant to invasion by alien species.

• The following features are shown by David Tilman.

• 1. Less year to year variation in the total biomass was shown in the plots with more species.

• 2.Higher productivity was shown by plots with increased diversity, thus species richness and diversity are essential to ecosystem health and survival of human race on the Earth.

BIODIVERSITY LOSS

• More than 2000 species of native birds have faced extinction due to the colonisation of tropical pacific islands by human being.

• There is an extinction of 784 species in the last 500 years according to the IUCN Red list-2004( 359-invertebrates, 338 vertebrates,87 plants.)

• Recently extinct animals-• 1. Stellers sea cow (Russia).• 2.Dodo bird (Mauritius).• 3.Thylacine(Australia).• 4. Quagga (Affrica)• 5. 3 sub species Tiger(Bali,Javan,Caspian)

Quagga (Affrica)

3.Thylacine(Australia).

. Stellers sea cow (Russia

2.Dodo bird (Mauritius)

Tiger(Bali,Javan,Caspian)

• In the last 20 years ,27 species have become extinct.

• Amphibians are more vulnerable to extinction, more than s15,500 species are facing extinction, presently the following face the threat of extinction.

• 1.31 % of gymnosperms.• 2.32 % of amphibians.• 3.12 % bird species.• 4.23 % of mammals.

• There have been five episodes of mass extinction since the origin of life on earth and evolution, but due to human activities the current rate of extinction is 100-1000 times faster than them.

Lose of diversity causes

• 1. Decrease in plant production• 2. Lowered resistance to environmental

perturbation.• 3.Increased variability in ecosystem processes

like water cycle, pest. plant productivity.

CAUSES OF BIODIVERSITY LOSSES.

• The EVIL QUARTET which describe the four major causes

• 1.HABITAT LOSS AND FRAGMENTATION• 2.OVER EXPLOITATION.• 3.INVASION OF ALIEN SPECIES.• 4.CO-EXTINCTION.

Habitat loss and Fragmentation• It is the primary cause for extinction.• Initially,14% of the land surface area were

covered by tropical rain forest but now only 6% of the land area is covered by them.

• The Amazonian forest called as the lungs of the planet are cleared for the cultivation of soyabean/converted into grassland for raising cattle.

• Many animals and plants are deprived from their home and face extinction due to total loss of habitat.

• Survival of many species is threatened due to the degradation of habitats by pollution.

• Animals required a large territory and those with certain migratory habitats are adversely affected leading to the decrease population when a large habitats becomes fragmented.

OVER EXPLOITATION

• Many species become extinct when nature is over exploited by man for natural resources. ex Stellars sea cow , passenger pigeon etc.

INVASION BY ALIEN SPECIES.

• Extinction of the indigenous species is caused when the alien species becomes invasive and compete with the native species.

• ex.The endemic species of Cichlid fish faced extinction on the introduction of Nile perch into Lake Victoria.(East Africa).

• Invasion of exotic species of plants like Parthenium,Lantana and Eicchornia pose threat to the survival of many native species.

• Introduction of African Catfish(Clarias gariepinus) for aquaculture is posing threat to the native cat fish C.bacterachus.

Cichlid fish

Eicchornia

African Catfish(Clarias gariepinus)

.African Catfish(Clarias gariepinus)

Native cat fish (Indian)C.bacterachus

Native cat fish (Indian)C.bacterachus.

Parthenium

Lantana

Passenger Pigeon or Wild Pigeon (Ectopistes migratorius)

co-extinction

• It is a phenomenon by which when a species become extinct, the plant and animal species association with it in an obligatory manner also become extinct.

• ex.On the extinction of fish, all those parasites which are specific to that fish also face extinction.

• co-evolved plant pollinator.

BIODIVERSITY CONSERVATION

• REASONS FOR BIODIVERSITY CONSERVATION.• 1.Narrowly Utilitarian .• 2.Broadly Utilitarian.• 3. Ethical.

1.Narrowly Utilitarian Reasons.

• These are obvious reasons .• Human beings derive a number of economic

benefits like food , fibre ,fire wood,resins,dyes, tannins, gums.

• Native people use about 2500 species of plants for traditional drugs/medicines.

2.Broadly Utilitarian Reasons.

• It includes ecosystem services which cannot be given a price tag. They are

• 1.Oxygen production.• 2.Pollination of flowers.• 3.Aesthetic pleasures like bird watching,

gardening. etc.

3. Ethical Reasons.

• It is an intrinsic value of each species.• It is our moral duty to care for their well

being.

APPROACHES FOR CONSERVATION OF BIODIVERSITY.

• THERE ARE TWO MAJOR APPROACHES .• 1.INSITU CONSERVATION (on-site

conservation)• 2. EX-SITU CONSERVATION( off –site

conservation)

IN SITU CONSERVATION EX-SITU CONSERVATION

1.It is the process of protecting the endangered species of plant or animals in the natural habitat.

It is the process of protecting the endangered species of plant or animals by removing it from the unsafe or threatened habitat and placing them under care of humans

2.It helps in recovering populations in the surroundings where they have developed their distinctive features

It helps in recovering populations or preventing their extinction under simulated conditions that closely resemble their natural habitats.

Ex. Biosphere, National parks, Wild life Santuaries, Sacred forest/lakes

Ex.Botanical gardens,zoos,seed/pollen banks,Gene banks,Tissue culture.

IN SITU STRATEGIES

• There are 425 biosphere reserves in the world, of which 14 are in India.

• 1.Nilgri, • 2.Nanda Devi.• 3.Nokrek.• 4.Manas.• 5.Sunderbans.• 6.Gulf of Mannar• 7.Great Nicobar.• 8.Agasthymala.• 9.Kanchenjunga.• 10.Pachmarhi.• 11.Similipal.• 12.Dehang-Debang.• 13.Dibru Saikhowa• 14.Achenankmar Amarkantak.

• Hot spots have been identified for maximum protection to the endemic and endangered species.

• There are 34 hotspots on the global basis,of which three are India ,THEY are

• 1.Western Ghats and SriLanka.• 2.Indo-Burma• 3.Himalaya.

NATIONAL PARKS AND WILD LIFE SANCTUARIES.

• According to September 2002 list. India has• 90 National parks.• 448 Wild Life Sanctuaries.• Jim Corbett National Park is the first

established in India.

SACRED FORESTS.

• These are undisturbed forest without any human intervention and they are surrounded by highly degraded landscapes.

• Such forests include a number of rare .endangered and endemic species.

• Ex.• 1.Khasi and Jaintia Hills of Meghalaya.• 2.Western Ghat regions of Karnataka and

Maharasthra• 3.Aravalli Hills of Rajasthan.• 4. Sarguja, Chanda and Boster areas of MP

EX SITU CONSERVATION

• INDIA has • 27 5zoological parks.• 35 Botanical gardens.• CRYOPRESERVATION is the method of

preservation by storage of materials at ultra low temperature for very long period.ex gametes of threatened species can be preserved.

CONVENTIONS OF BIODIVERSITY

• 1. THE EARTH SUMMIT.• This is the historic convention on Biological

diversity held in Rio De Janerio in 1992.• It is called upon all the nations to take

appropriate measures for• 1. conservation of biodiversity.• 2. Sustainable utilization of the benefits from

biodiversity.

The World Summit on SustainableDevelopment

• This was held in 2002,in Johanesburg ,South Africa.

• 190 countries signed commitment to achieve a significant reduction in the current rate of biodiversity loss at global level and local levels by 2010.

• BIODIVERSITY :- It is the term used to describe the combine diversity at all the levels of biological organization.

• ECOLOGICAL DIVERSITY :- The diversity at the ecosystem level .

• ENDEMISM :- It is the condition when species confined to that region and not found anywhere else.

• GENETIC DIVERSITY :- The High diversity shown by a single species at the genetic level(distributional level .)

• SPECIES AREA RELATIONSHIPS :- The relation between species richness and area.

DIFFERENCES

• Alpha Diversity

• 1. It refers to the diversity of the organism sharing the same habitat or community.

• 2. It is within community diversity. • Beta Diversity • 1. It refers to the diversity of the organism in

different communities in a habitat. • 2. It is between community diversity

• Ex-situ Conservation • 1.It is called off-site conservation.• 2.Includes botanical garden, zoos, gene bank,

seedlings etc.

• In-situ conservation• 1.It is called on-site conservation.• 2.It includes wildlife sanctuaries, national

parks, as well as protected areas to protect endangered species in natural habitats.

ASSIGNMENTS LEVEL1

• 1. What is the approximate no of plant and animal species described so far by IUCN (2004) report?

• 2. Which type of graph curve is obtained when species richness is plotted against area?

• 3. Name a few weeds that have invaded our crop fields as alien species. Why these have become uncontrollable

• 4. Categorize the following into in-situ and ex-situ approaches of biodiversity conservation.

• i) Botanical gardens ii) Wild life sanctuaries iii) Gene bank iv) Biosphere reserves v) Sacred forests/lakes vi) Pollen banks vii) Tissue culture viii) Cryo-preservation

• LEVEL2 • 1. Reserpine is obtained from a plant found in

Himalayan ranges. Name the plant. • 2. Western Ghats have greater amphibian

species diversity than Eastern Ghats. Why? • 3. Who proposed rivet popper hypothesis?

Describe this hypothesis briefly. • 4. Which type of organism are prone to co

extinction and why ?

• 1.The invasion of alien species is responsible for extinction of the indigenous species. Give 2 examples to support this statement.

• 2.. If a speices of fish becomes extinct, all those parasites, specific to that fish also face extinction. Which of the major cause describe as ―the evil Quartet‘s is being accounted

• 3. Categorize the followings statement into narrowly utilitarian, broadly utilitarian and ethical reason:-

• i) Every species in biodiversity has an intrinsic value even if it not of value to us. ii) Human beings device a number of economic benefits like food, fiber etc from biodiversity. iii) Biodiversity provides ecosystem services which can not be given price tag. Justify your categorization also.

• 4. Since the origin of life on earth and evolution there have been 5 episodes of mass extinction, but the current rate of extinction is 100-1000 times. What are the main causes of high extinction rate and how is it going to harm human beings

• QUESTIONS FOR SELF EVALUATION • 1 What is IUCN Red list ? Give any two uses

of this list .• 2Name any 2 threatened animal species of

India . 3Which are the biodiversity HOT Spots in India ?

• 4Name two alien species introduced in India .

• 5What is the importance of sacred forests and sacred lakes ?

• 6What is cryo preservation ?Give its one use .

• 7What are the major causes of species losses in geographic regions ?