Charles Darwin And Natural Selection

1920 WORDS

Charles Darwin And Natural Selection
Charles Darwin revolutionized biology when he introduced The

Origin of Species by Means of Natural Selection in 1859. Although Wallace had
also came upon this revelation shortly before Origins was published, Darwin had
long been in development of this theory. Wallace amicably relinquished the idea
to Darwin, allowing him to become the first pioneer of evolution. Darwin was not
driven to publish his finding, which he’d been collecting for several years
before Wallace struck upon it, because he had "never come across a single
[naturalist] who seemed to doubt to permanence of species" (Ridley, pp. 70).

What follows are the key points of Darwin’s Theory of Natural Selection taken
directly from the two chapters concerning it in his book Origins. In chapter III
of Origins Darwin sets up his discussion on Natural Selection by establishing
the struggle for existence in nature. By this he means not only an individuals
need to fend of enemies and survive its environment but also it’s ability to
create living, healthy, successful offspring. The first factor concerning this
struggle is the ratio of increase in any given species. Darwin explains how this
struggle must be occurring otherwise a single species would dominate the entire
earth because every single one of it’s offspring would survive. This is due to
the fact that every species reproduces exponentially, a rate that would soon
produce astonishing numbers if left unchecked. This does not happen however,
because nature has a system of checks and balances. Although we may not be able
to detect these checks, we can see their effects by the indisputable fact that
one species doesn’t completely dominate the planet. These checks consist of
enemies eating the young or even adults, the rigors of weather or environment,
and countless others. In this way birds, for example, cannot populate beyond
their food supply, and the grains they feed on are held in check, because even
though they may produce thousands of seeds only a few are able to reach
maturity. Darwin goes on to show how all plants and animals compete and relate
to each other in this struggle for existence. He does so by relating various
personal observations that show the introduction of a different species of plant
or animal can have a direct effect on the present survival of the indigenous
species and even allow other foreign species to proliferate. This leads to
interspecies survival, which Darwin considers the hardest struggle of all, and
the one that may have the greatest effect on the evolution of a species through

Natural Selection. It springs forth from the similarity in "habits and
constitution". Plants and animals of the same species must compete for the
same food and the same space to live in. Also, the original make-up of a plant
or animal may give it an advantage to thrive in an ever-competitive environment.

This brings us to Natural Selection and survival of the fittest that Darwin is
most known for. Darwin begins chapter IV by comparing human selection to
nature’s ability to select, dubbing his theory Natural Selection, and
explaining how imperceptible it is for us (at least science in his time) to
examine the minute changes slowly taking place in nature. Variations in a
species now come into play, and how these adaptations concern Natural Selection.

Slight differences in an individual of a species will give rise to two
situations. One is that it will be an injurious variation, which will definitely
lead to the death of the individual because of the aforementioned struggle for
existence. The other is a favorable adaptation in the individual's ability to
gather nutrients, survive its enemies, survive its environment, etc. The chance
of this individual surviving is greater than its less adapted competitors,
however slight, which gives it a better chance of leaving progeny. These progeny
will also have these abilities, increasing their chances of survival. Changes in
the young can also bring about changes in the adult, as the individual
approaches maturity, due to the difference in its original constitution. Once
again, it will possibly leave new traits to it’s progeny (if they are
advantageous and this variation doesn’t die out), spreading the variation
throughout the community and continuing the cycle of evolution. This is also
known as ordinary selection because it begins with one individual and it’s
constitution and habits. Another method of Natural Selection is sexual
selection. Sexual selection arises from interspecies cross breeding. This,

Darwin explains, deviates from the struggle for existence and becomes the
struggle for progeny. Advances in an individual will often allow

Read the full essay 1920 words