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Chapter 2. Facts about Ecosystems
An ecosystem is a natural area
containing living organisms that react to each other and to their
environment. Whether or not your reconstruction of a
paleoecosystem is valid will depend on great deal of your knowledge of
present-day animals and plants, their environments, and their effects
upon each other. You probably know more about this than you
realize.
By way of television, motion
pictures, radio, magazines, books and recording, you have learned much
about environments. Documentaries, travelogues, and
fiction-including science fiction-have taken you from pole to pole,
beneath shallow and deep ocean waters, to deserts, mountains, marshes,
swamps, plains, rivers, and lakes. Indeed, you have seen natural
areas through the four seasons, and you have observed the effects of
these environments on living creatures. But this is not all.
At zoos, natural history
museums, or aquariums you have seen how living creatures are adapted to
their environments. You probably have seen birds and mammals from
the tropics, fishes and snakes from many places, bears and penguins from
polar regions, cats from several continents, and antelopes and camels
from Africa and Asia. All of these animals exhibit different kinds
(and, in many instances, colors) of scales, feathers, fur, beaks, claws,
teeth, ears, hooves, and eyes. Each of these features is the
result of environmental adaptation.
You have witnessed even more
than this, though you may not have been aware of it. You are a
reacting organism-affecting and being affected by members of your own
and other species. Have you ever brought living things home from
an excursion? Trapped snakes? Caught fish? Have you
ever been bitten by a bee or a mosquito or clawed by a cat or dog?
Describing scenes or events that
probably happened more than a million years ago takes imagination as
well as knowledge. Everyone has some of both. Thus, when the
time comes for you to describe such scenes, let yourself go!
Speculation is very much a part of science.
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