November 24, 1859, many people simply believed that species were created by God
in their present forms, or that it was possible for organic matter to be spawned
from inorganic matter. However, Charles Darwin used these ideas to create his
thesis, On the Origin of Species by Means of Natural Selection. The first true
theories on evolution arise during the classical Greek period. On a handful of
Greek philosophers believed in the theory of evolution and natural selection.
Unfortunately, the two philosophers who influenced western civilization the
most, Plato and Aristotle, opposed any theory of evolution. Plato believed that
there were two worlds, one real world, and one imperfect world that we perceive
with our senses. Any variations in life were imperfect images of their ideal
forms. However, Aristotle didn’t believe in two worlds; instead, he believed
in a “scale of nature.” Each life form was arranged on a type of
“ladder”. It started at the bottom with the least complex organism and
continued up to the most complex organism. Each organism had a pre-determined
“rung”, which allowed no ability to move up, and no open spaces for a new
organism to fill. According to Neil Campbell in his book, Biology: Fourth
Edition, “Juedo-Christian culture fortified anti-evolution theories.” (p.
400-401) The creationist-essentialist dogma that species were permanent and
created for a specific purpose became deeply embedded in Western thought. Any
person who dared to theorize or believe in theories about evolution were
instantly labeled heretics. The medieval church saw evolution as saying that God
did not exist, that we are not the “supreme creation”, and that humans could
just be evolutionary mistakes. However, in the later 1700’s and early 1800’s
there was a “scientific revolution” taking place. People began to use
scientific experiments to explain what they had always put faith in. According
to Campbell, the first big step in the development of the theory of evolution
was made by Carolus Linnaeus. (p. 400-401) Linnaeus was the founder of taxonomy
and developed the naming system for organisms that we still use today. He
grouped organisms based on similar characteristics. This, for Darwin, would
become a focal point of his theory of evolution. When Darwin began his research
aboard the H.M.S. Beagle in 1831, he had some pre-constructed ideas. The first
was that he rejected Plato’s, Aristotle’s, and the Church’s ideas that
organism were made the way they are, and will never change. The second was about
Linnaeus’ filing system; Darwin believed that similar species must of evolved
from similar ancestors. During his trip on the Beagle, Darwin collected 13
different types of finches that he believed were different species. When he
returned to Great Britain in 1836, he learned from ornithologists that the 13
different types of finches he collected, were indeed separate species. This
discovery led Darwin to theorize that if a species was isolated, then it would
adapt to fit it’s surroundings; just like how the finches adapted new beaks
depending on their native types of food. Finally in 1844, Darwin wrote an essay
on his theory of natural selection and the origin of species. When Darwin
finished his book on evolution, The Origin of Species, he had two major ideas:
the first was that evolution was the explanation for life’s unity and
diversity; the second was that natural selection is the cause for adaptations.
Darwin provided numerous example of his theories, but he was still doubted.
However, on of his modern day supporters named Ernst Mayr has provided his own
theories and proof of Darwin’s ideas. With respect to Darwin’s ideas on
natural selection and adaptation, Mayr used an closely related group of insect
species to prove this point. In Malaya round, pink flowers are common; so the
mantid native to Malya is round and pink. However, in Central America, most
plants have green, oval-like leaves; so the mantid to Central America is green
and oval-like in shape. This example shows how species of common ancestry have
adapted to fit their individual surroundings. With respect to Darwin’s ideas
on evolution, we will look at the mustard plant. The mustard plant is the
evolutional ancestor of six different vegetables: cauliflower, cabbage, brussels
sprouts, broccoli, kale, and kohlrabi. Breeder have been able to prove this by
focusing on one particular part of the plant to accentuate. The process of
accentuating the plant parts by breeders is evidence of evolution, except that
humans are manipulating the results to meet their own needs. There really is not
much more information on Darwin’s theory of evolution, due to the fact that
the majority of his book focused on adaptations rather than evolution. So, as
you can see, Darwin’s disbelief in the notions that evolution occurred, caused
him to investigate evolution, and led to the creation of Darwinism. Darwin did
present a great deal of evidence to prove his point, however, his theory still
has one major problem; the “missing link”. Darwin was able to show evolution
from the simplest organism to the most complex organism as a complete chain;
except that he is missing the link between primates and humans. In spite of all
the evidence and the “missing link”, Darwin’s ideas are still being
debated to this day; however, most biologists now believe in Darwinism and
support Darwin’s ideas on evolution and natural selection.