=======================Electronic Edition========================
RACHEL'S ENVIRONMENT & HEALTH WEEKLY #441
---May 11, 1995---
NEW PERSPECTIVES ON LOSS OF SPECIES
Conservative estimates indicate that the present rate of species loss is about one species per year for every 10,000 species on Earth. Extinctions are occurring now at a rate 100 to 1000 times as fast as "natural background" rates of extinction. "The "natural background" is the rate of extinction measurable in the fossil record of life before humans appeared on the scene. Extinction is nothing new; it has been going on since life first emerged on Earth, perhaps 3 billion years ago(Rachel's 1)." Harvard biologist E.O. Wilson estimates that there is somewhere between 5 and 30 million species in existence.
"When a species is lost, all of the genetic information that it contained is lost as well. If a species has valuable characteristics --like the bread mold that gave us penicillin --its loss is particularly important to humans (Rachel's 1)." All species are important because we do not know or understand exactly what holds the web of life together. If we continue dismantling the web of life at the present rate we may be reducing the functioning capabilities of that systems. The loss of the many parts of nature may weaken the whole structure that we rely upon to life on this planet in ways that we cannot yet understand or appreciate.
Since 1970, mounting evidence indicates that amphibians are declining and disappearing all over thw world.
Out of 4000 species of frogs and toads it is beleived that only 5 of those became extinct between the 19th century and the 1960s. In the past 25 years, herpetologists have seen declines and disappearances of many more species. It is now suspected that 89 amphibian species are threatened, endangered or near extinction.