Life appeared on earth about 600 million years ago, according to fossil records. New types of plants and animals evolved in response to changing conditions. Today, somewhere between 5 million and 50 million different species exist on earth. Biologists from all nations have recognized the existence of only 1.5 million species, in the sense that they have been given Latin names. In many cases, even named species have not been studied in any detail.
The best estimate is that half of all species now living on the planet will become extinct in the next 50 to 100 years as a result of human activity, according to Princeton University's Dr. Robert May (now moved to the faculty at Oxford University in England). [See SCIENCE magazine Vol. 241 (September 16, 1988), pg. 1448.]
The loss of species affects us all in very practical ways. The planet earth is an exceedingly complex machine with all its parts interrelated and interdependent. You can compare it to a TV set (though a TV set is vastly more simple). Killing a species is like ripping a transistor out of a TV set, hoping to improve the set's performance.
More than 95% of all pharmaceutical drugs in use today were
produced by nature and discovered by humans--they were not
invented by humans. Loss of species will rob our children of
nature's storehouse of biological inventions. Before our children
have even had an opportunity to find out what benefits might be
derived from most species, they'll be extinct, gone and, with
them, whatever benefits they held.
--Peter Montague, Ph.D.
Descriptor terms: biological diversity;