BIODIVERSITY AND ENDEMISM

Biodiversity The variety of genes, species and

ecosystems in an area. It is a measure of the variety of living

things and their genetic variations. Totality of the genes, species and

ecosystems in a region.

The main aspects of biodiversity are Genetic diversity Species diversity and Ecosystem diversity

ASPECTS OF BIODIVERSITY

GENETIC DIVERSITYGenetic variability within one species.

SPECIES DIVERSITYNumber of different species in an area

ECOSYSTEM DIVERSITYThe range of different habitats, ecosystems and niches in an area.

SpeciesGroup of organisms with so many features

in common that they can mate and produce sexually viable offspring.

Species richnessNumber of different species in an

ecological community at a particular time.

Gene poolSet of all genes or genetic information in

any population.A large gene pool indicates extensive

genetic diversity and high chance of survival.

Measuring biodiversity within a habitat

Species richnessThe simplest way to measure

biodiversity is to count the number of different species in an environment.

Genetic diversityIf there are a large number of alleles

of each gene, then they have higher genetic diversity.

Simpson’s index It is a measure of diversity.

This takes into account the number of species present as well as the relative abundance of each species.

It is measured by using the formula

D = Σn(n - 1) N(N - 1)

where N = the total number of organisms of all species and

n = the total number of organisms of a particular species

from which Simpson’s Diversity Index, 1 – D, is found.

It ranges from 0 to 0.9999

High species diversity increases the chance of species survival.

Endemism and biodiversity The situation where a species is found

only in one particular area

Species of plants and animals which are found exclusively in a particular area is called endemic species.

Endemism occurs when species are separated and cannot interbreed.

There is a possibility to become two different species. (speciation)

Genetic diversity is very low.

Areas with many endemic populations are very vulnerable to the changes in the environment.

Example : red kangaroo found only in Australia

Biodiversity ‘Hotspots’

It is a biogeographic region that is both with significant reservoir of biodiversity and is threatened with destruction.