The earth's ecosytems are complex ecological environments which
have developed over billions years. The intricate componets of an
ecosystem cannot be severely altered because the changes will affect
its success. However, humans harm the environment by causing global
warming, habitat destruction, acid deposition, and environmental
estrogens. The aspects of human interference that we will be
covering are the role of acid deposition, the discovery of deformed
frogs, and the results of environmental estrogens. Each effect
demonstates the conflict between humans and their surrounding species.
Acid deposition results from human interference in ecosystems.
Scientists define acid deposition as the process of depositing acidic
pollutants from the earth's atmosphere to its surface. Although it
was an unanticipated side effect, it has become a large concern. Data
suggests that humans cause 95% of the acid deposition that occurs on
earth. Nitrogen and sulfur oxides from automobiles and industry are
the major sources of acid deposition. Effects on the soil include
cation depletion, aluminum mobilization, and pH depression. This type
of pollution also greatly affects both aquatic and forest ecosystems
by shifting the species diversity and inhibiting chemical processes.
Countries have now taken action and established regulations to help
reduce this problem.
During the month of August 1995 a group of students from the Minnesota New Country School in Le Seur made a startling discovery. The students visited the Ney Pond to catch a glimpse of nature, but instead found frogs that were grostesquely deformed. In the last two years deformed frogs have been found across the country. Their discovery has started a national search for the cause. The cause for these deformities has been a mystery, but scientists come up with these main theories; natural parasities, increased ultraviolet radiation due to the hole in the ozone layer, viruses, algea bloom, predators, pesticides. Frogs don't occur in nature at such alarming numbers. The frog deformities are the result of human effects on the ecosystem.
Playing the canary in a coal mine, wildlife often shows signals
first, that something is seriously wrong in the environment. This is
the case with a group of pollutants, most of which were first designed
as pesticides, that by chance have hormone-mimicking properties.
There is now evidence that these environmental estrogens are causing
problems in humans as well. This is a classic example of humans
having adverse effects on their environment, and eventually on
ourselves. These compounds that were designed to be harmless insect
killers, have turned out to have much more drastic consequences.