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Monday, April 06, 2009

Variety Means Life

When you look at the world around you, have you ever wondered why there is so much diversity?

Studies suggest that there are between five and 100 million living species today. It sounds like a really big number but the truth is it is only a tiny fraction of all the species that have ever lived.

Species become extinct if they can't adapt quickly enough to circumstances or when competitor species dominate the present resources.

Ginkgo tree, Coelacanth fish and crocodiles have remained unchanged for millions of years that they are nicknamed 'living fossils'.

However, scientists believe most species exist for some 10 million years and then become extinct. This means just one in a thousand ever to exist remains living today.

Diversity is important for many reasons. In the short term, biodiversity is important because the bigger the range of living species, the more food, medicines, and natural resources we have.

High biodiversity also controls the spread of certain disease because viruses have to adapt to infect different species. Monoculture, growing just one species in one area, had led to many disasters.

For example, when Asia's rice farmers crops were destroyed by the Rice Grassy Stunt Virus in 1970s, scientists discovered only one out of 6,373 species of wild rice was resistant.

If there hadn't been so many alternatives available, rice crops may have suffered for decades. More importantly, as all lives on Earth are interconnected, biodiversity ensures we have fresh air, clean water and productive soils.

Now that so many species are threatened, we need to maintain as many different types of habitat as possible (ecological biodiversity), as many individual species as possible (genetic diversity) and as many kingdoms, phyla, and species (organismal diversity) as possible.

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