|
Darwin and Natural Selection
Who was Charles Darwin?
 |
Charles Darwin |
The diversity of the living world
has long inspired naturalists and scientists to speculate on
its origin. Up until the 19th century,
the most popular explanation for the diversity of life on Earth
was a supernatural force or god(s). It wasn’t until Charles Darwin’s
work in the mid-1800s that the scientific and lay communities
began to seriously consider the possibility that life evolved
from ancestral
forms by strictly natural processes.
As a naturalist aboard
the H.M.S. Beagle, Darwin made observations – particularly
in the Galapagos Islands —that would later be the foundation
for his theory of evolution. What distinguished his theory from
others at the time — such as Jean-Baptiste Lamarck’s theory
of evolution by the inheritance of acquired traits — was his
proposal of natural selection as the mechanism.
What are the principles
underlying the theory of evolution?
Darwin was acquainted with
principles set forth by the economist Thomas Malthus, who wrote
of overpopulation in the context of
human civilization. Malthus observed that humans produce more
offspring than
their food supply can support, which makes competition for limited
resources inevitable. Darwin saw connections to the natural world,
where habitats are often populated by organisms that have a much
greater capacity to reproduce than the environment has the capacity
to support.
Darwin was also knowledgeable about the practice of artificial
selection, where humans essentially direct evolution by manipulating
heredity.
Applying these ideas to the natural world, Darwin envisioned
a “struggle for survival” where those that survived were
somehow more “fit” — that is, better suited for that
particular environment. Darwin proposed that “survival of the
fittest” resulted in differential reproduction, where those individuals
in a population that possessed beneficial traits would produce
more offspring. This was natural selection, where nature "selects"
which variants
in a population survive and reproduce. Darwin proposed that,
over time, natural selection results in evolution.
In 1859,
Darwin published his life’s work, “The Origin
of Species.” The theory of evolution by natural selection rocked
the scientific community as well as the public. Interestingly,
another scientist, Alfred Russell Wallace, had conceptualized evolution
by
natural selection. Darwin, however, generally receives the credit.
|
Darwin
and Natural Selection
prev:
artificial selection