Introduction To Evolution
...have developed from primitive organisms through changes occurring over billions
of years, a process that includes all animals and plants. Exactly how evolution
occurs is still a matter of debate, but there are many different theories and
that it occurs is a scientific fact. Biologists agree that all living things
come through a long history of changes shaped by physical and chemical processes
that are still taking place. It is possible that all organisms can be traced
back to the origin of Life from one celled organims.
The most direct proof of evolution is the science of Paleontology,
or the study of life in the past through fossil remains or impressions, usually
in rock. Changes occur in living organisms that serve to increase their
adaptability, for survival and reproduction, in changing environments. Evolution
apparently has no built-in direction purpose. A given kind of organism may
evolve only when it occurs in a variety of forms differing in hereditary traits,
that are passed from parent to offspring. By chance, some varieties prove to be
ill adapted to their current environment and thus disappear, whereas others
prove to be adaptive, and their numbers increase. The elimination of the unfit,
or the "survival of the fittest," is known as Natural Selection because it is
nature that discards or favors a particular being. Evolution takes place only
when natural selection operates on apopulation of organisms containing diverse
inheritable forms.
HISTORY
Pierre Louis Moreau de Maupertuis (1698-1759) was the first to
propose a general theory of evolution. He said that hereditary material,
consisting of particles, was transmitted from parents to offspring. His opinion
of the part played by natural selection had little influence on other
naturalists.
Until the mid-19th century, naturalists believed that each species
was created...
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