Friday, November 1, 2013

Biodiversity - Genetic, Species and Ecosystem diversity

Biodiversity is defined as "the variety and variability among all groups of living organisms and the ecosystems in which they occur."

Biodiversity is classified into three types:
  1. Genetic diversity
  2. Species diversity and
  3. Community or Ecosystem diversity
Genetic diversity - A species with different genetic characteristics is known as a sub-species or "genera".
Within individual species, there are varieties, that are slightly different from one other. These differences are due to differences in the combination of genes. Genes are the basic units of hereditary information transmitted from one generation to the other.
Ex: (i)  Rice varieties -All rice varieties belong to the species "oryzasativa". However there are thousands of rice varieties that show variation at the genetic level in the form of different size, shape, colour and nutrient content
       (ii)  Teak wood varieties: The various teak wood varieties available are - Indian teak, Burma teak,       Malaysian teak etc.
Species diversity - A discrete groups of organisms of the same kind is known as species.
Species diversity is the diversity between different species. The sum of varieties of all living organisms at the species level is known as species diversity.
The biotic component is composed of a large number of species of plants, animals and microorganisms which interact with each other and with the abiotic component of the environment
Ex: The total number of species living on earth is approximately more than 2 million. However, only around 1.5 million are found and assigned scientific names
Plant species: Apple, Mango, Wheat, Grapes, Rice etc
Animal species: Lion, Tiger, Elephant,Deer etc
Community or Ecosystem diversity - A set of biotic components (plants, animals and microorganisms) and abiotic components (soil, air, water, etc) interacting with each other is known as an ecosystem.
The diversity at an ecological level or habitat level is known as ecosystem diversity.
Ex: River ecosystem
Rivers include fish, aquatic insects, mussels and a variety of plants that have adapted.
Ecosystem diversity is the aggregate of different environmental types in a region. It explains the interaction between living organisms and physical environment in an ecosystem.

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