Tuesday, March 31, 2009

Know the Biodiversity of Life forms

Biodiversity is the occurrence of all life forms in the biosphere. The phenomenon of speciation increases biodiversity. Biodiversity can be for a specific region or geographical area and similarly can be within a species. Within a species there can be varieties or sub-species, strains, and types. This variation within a species constitutes the biodiversity within a species. It is directly linked to the stability of the ecosystem. The magnitude of the biodiversity is not completely studied. The total number of species collected, named, and classified in taxonomic groups is around 1.5 million. This number is only a small fraction, about 10% of all living organisms, in this biosphere. The remaining, more than 90%, remains to be identified and classified.

Out of this 1.5 million known species, 750,000 are insects. The remaining part includes 280,000 animal species and 250,000 numbers of plant species. There are approximately 69,000 fungi, 27,000 algae, 3,000 protozoans, and about 3,000 prokaryotes including eubacteria and archaebacteria. Among these known groups, some have been studied extensively and others have been studied very poorly. Biodiversity, which is created by speciation and evolution, has a direct impact on the stability of the ecosystem and the biosphere. Due to many man-made changes in the environment through deforestation and construction of big dams, there is disturbances in the habitat of the species, slowly leading to their mass extinction and destabilization. This loss of biodiversity is non-reversible unless we take special precautions. The phenomenon of extinction is opposite to that of speciation. Extinction is the ultimate fate of all species.

Reasons for Extinction : The reasons for extinction are numerous. A species can be competitively excluded by a closely related species, the habitat a species lives in can disappear, and/or the organisms that the species exploits could come up with an unbeatable defense. Some species enjoy a long tenure on the planet while others are short-lived. Some biologists believe species are programed to go extinct in a manner analogous to organisms being destined tc die. This is ordinary extinction. The majority, however, believe that if the environment stays fairly constant, a well-adapted species could continue to survive indefinitely.

Mass extinctions: Mass extinctions shape the overall pattern of macroevolution. If you view evolution as a branching tree, it's best to picture it as one that has been severely pruned a few times in its life. The history of life on this earth includes many episodes of mass extinction in which many groups of organisms were wiped off the face of the planet. Mass extinctions are followed by periods of radiation where new species evolve to fill the empty niches left behind. It is probable that surviving a mass extinction is largely a function of luck. Thus, contingency plays a large role in patterns of macroevolution.

Tags: Bio Technology, Bio Genetics , Genetic Variation

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