Pre-Darwinism Views
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.