Essay/Term paper: Lamarck's influence on the development of darwin's theory of evolution

Essay, term paper, research paper:  Philosophy Essays

Lamarck's Influence on the Development of Darwin's Theory of Evolution


Dec. 4 1996
Marc Weinstein

There have been many ideas on the theory of evolution. Some simply take our
existence for granted, others prefer to explain all evolution in terms of the
bible and the presence of a God. However, there are those who have researched
the topic of evolution and have offered an explanation as to where a species
comes from and how they evolved in the manner that they did. This type of
science has been studied for a very, very long time, and one of the most famous
minds in the field of evolution was a man named Charles Darwin. Darwin was not
the first one to offer theories on evolution. There have been many scientists
who preceded him. These earlier evolutionists came up with models of evolution
that were unfortunately unworkable. One of these early pioneers was Jean-
Baptiste Lamarck. Lamarck believed in deism and advocated natural religion based
on human reason. He believed in the harmony and rationality of the world. And
although flawed, the work of Lamarck did not go unnoticed, however. Darwin also
believed in the harmony of the world, and it was Darwin himself who said that
Lamarck was the first man whose conclusions on evolution brought about
excitement and attention. He was the one who showed law in organic and inorganic
species evolution. As it turned out, the work of Lamarck was quite influential
on Darwin. Lamarck's views on inheritance of characteristics can be seen in
Darwin's accounts of natural selection. When Lamarck wrote of transmutation,
Darwin followed with his beliefs of the mutability of species. As well, Darwin
had used Lamarck's ideas on use and disuse of organs. Lamarck was not the
greatest of influences on Darwin, but he was an important one.

One of the most important arguments in Darwin's theories was the idea of natural
selection. It is generally thought that the world first heard of this idea in
the form of Lamarck's inheritance of acquired traits theory. Lamarck's work
showed that organisms improve themselves on their own. Then these new advantages
for the environment would be passed on to the species offspring on the genetic
level. This idea of self improvement detailed how, through hard work of the
organism, the path of evolution was continuous, always improving to the point of
perfection. Lamarck had said that organisms must first be faced with a different
mode of environment that would trigger some sort of pressure for an altered gene,
to be inherited in the next generation. This process has come to be known as
Lamarckism. (Gould, 1980) Darwin did not deny any of this. He regarded it as
support for natural selection as an evolutionary mechanism. Darwin's theory was
more complex then Lamarck's, but the basic structure was there. Darwin had
rooted his theory on the concept of adaptation, just as Lamarck had previously
done. Adaptation is the notion of organisms responding to a changing
environments by evolving either a form or function of the body that would better
suite it in the environment. Lamarck had explained that the method of transfer
of information was directly to the organism, the animal would perceive the
change and simply respond in the necessary way so that their offspring can be
better adapted. Darwin's answer to what the mechanism is was much different.
Darwin spoke of there being two components, variation and direction.(Gould,
1980) Darwin had taken into account that the species did indeed create offspring
that were better suited for the environment, just as Lamarck had said. Darwin
proposed that instead of direct transfer of environmental change, those that
vary by good fortune are better suited for the environment and leave more
surviving offspring. A species would have this beneficial trait through random
variation. Then, the characteristic would help the animal survive, while the
others died off. This ensured that the beneficial trait would get passed on.
This explanation is similar to Lamarkism, with obvious adjustments. Darwin
simply showed that natural selection is, above all, a theory about the struggle
of individual survival and reproduction. Lamarck's theory on inheritance of
acquired characteristics is not that much different, infact, Lamarckism has
occasionally been mistaken for Darwinism. Darwin did indeed take Lamarck's
inheritance of characteristics theory and modify it so that he improved upon it.
This shows how Lamarck influenced Darwin to create the natural selection theory.
It did not stop there, though. Lamarck also influenced Darwin with the idea of
transmutation, and prompted Darwin to theorize on that aspect of evolution as
well.

Transmutation was an idea resulting in the problem that Lamarck faced when
dealing with the apparent extinction of a species. To Lamarck, extinction was
not a possibility. Lamarck believed that extinction could not occur because then
it would mean that God created an imperfect being, which was not a possibility
for Lamarck. One purpose for the theory of transmutation was to offer an
explanation for the apparent "disappearance' of a species. The theory was that
out of inherited characteristics, a species would undergo change. Each
generation would continue to change because inheritance of traits would always
occur. Eventually, over a very gradual amount of time, the species would evolve
so dramatically, that the new adaptations would bear little or no resemblance to
the original species.(Ospovat, 1981) Darwin, who incorporated this idea,
modified it slightly. To Darwin, extinction was very much a reality. He had
stated in his "Origin of Species" that only few species in a particular genus
would ever undergo a change. The other species of the same genus would go
extinct and leave no modified offspring, only the ones that have apparently gone
through some sort of mutation would produce offspring. This theory shows a
direct link to Lamarck's because Darwin believed in transmutation also. On his
voyage to the Galapagos Islands, Darwin found birds that seemed to be similar,
but were each distinct. These birds came to be known as Darwin's finches, and
Darwin discovered that each variety shared a common ancestry that grew out of
the mainland. Although his method for scientific analysis was poor, Darwin
concluded that when the same species of birds had migrated to the different
islands of the Galapagos, they found that their competition for survival had
decimated. The finches would then evolve to fit the new feeding environment, and
take over the roles of the previous birds. (Gould, 1980) This idea was
influenced by Lamarck's principal that each newly established evolutionary line
would gradually move up the ladder. In Lamarckism, transmutation and inherited
characteristics went hand in hand. Transmutation occurred out of the willingness
of the organism to adapt to the environment. Although Darwin's theory of mutated
animals is a bit different, again the influence of Lamarck is apparent. To
Darwin, transmutation was not the achievement of higher levels of organization,
but rather the production of new forms better suited for life in the external
environment. Although this seems the opposite to Lamarck, Darwin merely tried to
show the scientific fact behind transmutation, he needed to involve extinction,
Lamarck did not, it was necessary to prove the notion of mutation and
transmutation because it was not regarded at the time due to the fact that the
steps in-between were not visible. Darwin saw the difficulty in Lamarck's view,
and was influenced by the evolutionist to come up with an idea that supported
the topic as a whole, not necessarily Lamarck's view. Darwin proceeded to try
and improve upon Lamarck's theory when the idea of use and disuse became of
interest to him.

The idea that an organism would have parts of their body disappear due to the
fact that the particular part was of no function over many generations and had
no use, was presented to Darwin by Lamarck. It was Lamarck who had said that if
he were to put a patch over the left eye of two children, one male and one
female, and the patch be kept there throughout their lifetime, and then in turn,
their children would also be given a patch to wear, that gradually over many
generations, the right eye would adapt so that the left eye would no longer be
needed. Lamarck was confident that distant generations would not even have a
left eye, and that further down the road, the right eye would start to move
towards the center.(Corsi, 1988) Obviously there would be no proof on this
particular hypothesis. Lamarck did not stop there, though. He also stated that
the giraffe's long neck was the result of continuous stretching for food atop
the highest trees. The will power of the giraffe changed the structure of it's
neck sothat future offspring would be able to reach for the best leaves. (Corsi,
1988) The idea of use and disuse is connected with the idea of inherited
characteristics as well. To Darwin, this idea showed him the correlation between
the environment and natural selection. He had stated that through the natural
selection of beneficial traits, the inheritance of use and disuse would help in
evolving a species to adapt to the surrounding conditions. Lamarck's theory on
use and disuse of structures within the organism is clearly shown here in
Darwin's work of the same manner, once again showing influence of Lamarck's
inheritance of traits on Darwin's theory of natural selection. The idea of use
and disuse is directly the result of natural conditions in the environment. If
an organism is better suited for the environment and has no use for a particular
appendage, for instance, that appendage would eventually get weaker and weaker.
Over time, that appendage would most likely start to become less and less
apparent, maybe to the point that it may start to shrink. This idea, which
Darwin advocated, was a theory of Lamarck.

When people talk of evolution, Darwin is usually a name that is mentioned most
often. He was arguably the most popular mind in the field of evolution. However,
he was not the only one, not by any stretch. Many scientists who specialized in
evolution preceded him. Darwin's work was influenced by theses earlier
evolutionists, and one of the most important person who directly influenced
Darwin was Lamarck. Lamarck however, was not always entirely correct when it
came to his theories on where a species came from, and how it got there. Using
the work of Lamarck, Darwin was able to improve upon theories that had the right
idea, but was curved by biblical belief or information unknown at the time, such
as the possibility of a species going extinct. Lamarck's theories on inheritance
of characteristics, transmutation and the use and disuse of internal structures
can be seen in the preliminary ground work of Darwin's theory of natural
selection, mutation of species and use and disuse of an organisms body parts.
Darwin had revolutionized the belief in evolution, and in doing so, he had
brought back some theories that were not all that popular when they were first
introduced. Great minds like Lamarck had influenced Darwin to show the world
where it originated, and how it progressed through the ages.

BIBLIOGRAPHY

1. Corsi, P., "The age of Lamarck", University of California Press LTD,
Berkeley and California, 1988

2. Gould, S.J., "The Panda's Thumb", W.W. Norton and Company Inc. New York,
1980

3. Gould, S.J., "The Flamingo's Smile", W.W. Norton and Company Inc. New York,
1985

4. Mayr, E., "One Long Argument:Charles Darwin and the Genesis of Modern
Evolutionary Thought", Harvard University Press, Cambridge Massachusetts,
1991

5. Ospovat, D., "The Development of Darwin's Theory", Cambridge University
Press, New York, 1981

6. "Index of the Origin of Species" Internet, http//www.cs.brandeis.edu/~
~rllc/texttract1.html