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Biodiversity

Drawing of a dinosaur (T Rex) © Shirley Burchill

Life has been evolving on Earth for over 3 billion years. Scientists have identified about 1,4 million different species. There are many more waiting to be identified, perhaps millions. This collection of vastly varied living organisms is our planet's biodiversity.

The richest parts of the planet's biodiversity are also the least well-known. It is estimated that 97% of all species on Earth live in the oceans below the zone where sunlight penetrates the water. On the continents, it is estimated that 50% of all land-dwelling species live in tropical rainforests. The first step towards preserving life on Earth is getting to know and understand it.

Throughout the history of the Earth, as new species evolve, other species become extinct. Overall, as time has progressed, there are more and more different kinds of organisms. The dinosaurs became extinct 60 million years before humans walked the Earth. What caused their extinction is still not fully understood but it was some sort of natural catastrophe.

Human activities today are exterminating species up to 10 times faster than they would naturally disappear. As the numbers of people increase, the numbers of species decrease.

Hippos, Kenya © Shirley Burchill

Hundreds of thousands of tourists visit Kenya each year. In 1989, tourism brought in 8640 millions of Kenyan shillings (or about 80 million pounds sterling).

Antelope, Kenya © Shirley Burchill

Why should humans save species?

If animals and plants become extinct naturally, why should humans worry about the ones that they exterminate? There are several good reasons to worry:

(a) Plants are a natural resource.

Rain forest plants, Costa Rica © Shirley Burchill

Many plants can make things that we cannot produce for ourselves in laboratories or factories such as medicines, oils or perfumes.

(b) Animals and plants are a source of pleasure.

 

Mountain view © Paul Billiet

Seeing an eagle soaring above a mountain or walking through a forest in springtime can be a great pleasure. In some parts of the world wildlife is an important source of income because tourists come to see the exotic organisms which live there. Kenya's savannas and Australia's coral reefs are just two examples. One does not need to go very far, however, to appreciate what nature has to offer.

(c) Humans are special animals who have a special responsibility.

Humans are the only animals which are able to make judgments about what is right and what is wrong from a moral or ethical point of view. Humans need to ask themselves:

Have we got the right to make a species disappear forever?

The Great Barrier Reef as an example of biodiversity

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© Paul Billiet, Shirley Burchill, Alan Damon and Deborah James 2010

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