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Cornfield
8.30.02
Science and Health:
The Earth Debate
More on This Story:
Genetic Diversity

Genetic biodiversity is about much more than the loss of the blue whale. It's about crop diversity and hunger rates, the way valuable ecosystems work, deforestation and food supplies in the water. While it is true that virtually all species that existed are now extinct, the rate of extinction is increasing.

What is especially important to realize is that only a small percentage of species have yet to be described at all. We have tended to focus on those closest to ourselves — mammals and birds are well documented, but we know relatively little about fungi, bacteria and other small living entities. An astonishing fact when you consider that penicillin is a simple mold. Scientists don't know the extent of the loss when a species is gone. They do know, however, that it is permanent.

Find out where all the flowers, animals and even crustaceans have gone.

     

On average, about three new species of birds are found each year, and as recently as 1990, a new species of monkey was discovered. Other vertebrate groups are still far from being completely described: an estimated 40 percent of freshwater fishes in South America have not yet been classified. ...


Ecosystems and Diversity:

Ecosystem degradation is an immense problem, losing one element can lead to the death of many species and whole chains of life. EARTH ON EDGE documented the effect that an invasive species, in this case trees, had on a delicate haven for genetic diversity in South Africa.

Forests: Tropical forests are the most species-rich ecosystems in the world. The world's forested area declined by about 2.4 percent in the 1990s, a loss of about 90,000 km squared per year.

Desertification: This growing phenomenon affects almost a quarter of the total land area of the world, and almost 70 percent of the world's drylands face further degradation. Often caused by overgrazing and overuse of marginal land, and closely linked to rural poverty and hunger, desertification threatens the livelihoods of over 1 billion people in 100 countries.

Fisheries: World waters provide direct and indirect livelihoods for some 400 million people. More than a quarter of the world's fisheries are over-utilized and half are exploited at full capacity. Overall, 75 percent of the world's fisheries require immediate steps to freeze or reduce fishing to ensure a future supply of fish.

Coral Reefs: Almost a quarter of the world's coral reefs have been completely destroyed, and another 20 to 30 percent are threatened with destruction within the next 10 years. Coral reefs are a crucial element in the food chain of the oceans.

Genetic Diversity Stats

% of world covered by forest:  30%
Net total loss of forest 1990 - 2000:  94 million hectares
% of the worlds fisheries requiring reduction or freezing of fishing:  75%
% of world's coastal ecosystems endangered by human activity:  Over 50%
% of world's land lost to production by human activity:  25%
# of wheat varieties used in China in 1949:
# of wheat varieties used in China in 1970:
 10,000
 1,000
% of corn varieties lost in Mexico since 1930:  80%
% loss of apple, cabbage, corn, tomato, pea varieties grown in the United States since 1804:  85 - 90%
United Nations Environment Program; The Convention on Biodiversity; Food and Agriculture Organization: World Wildlife Fund

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