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Author Topic: The Difference between Lamarck and Darwin’s Theories of Evolution:  (Read 34429 times)

Offline McQueen

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It is fascinating to remark on the differences between the theories of Lamarck and Darwin. A superficial glance does not reveal any great difference between the two theories and those that do exist are not immediately apparent.
   Lamarck, Darwin’s predecessor in evolutionary theory, held that (a) species underwent changes in response to changes in their environment. One notable example quoted by him was the case as it might exist with respect to Giraffes. Lamarck contended that as trees began to grow taller, giraffes responded to the change by growing longer necks so that they could continue to feed.   His second contention was that (b) that this change was permanent for as long as the new environmental conditions continued to apply. In other words, nature chose the best possible solution and organisms (species) responded accordingly.
Darwin (and Wallace’s) theory was one of natural selection and survival of the fittest. As the environment underwent changes, the species affected by these changes underwent changes in response to changes in the environment. On the face of it there is not much dissimilarity between the theory proposed by Lamarck and that of Darwin. What does make a difference is that Darwin proposed a mechanism whereby such changes were effected. Changes in species was due to procreation or breeding. Those species that spawned changes that adapted to the new conditions, survived while those that didn’t fell by the way side.
With this relatively rudimentary distinction between the two theories, the vast differences  between the two  becomes apparent.  Lamarck envisioned, with no experimental observation to back his hypothesis, changes taking place singly and automatically in response to changes in the environment, corresponding to a mechanical working of nature; the environment underwent a change and nature underwent a change. By contrast, Darwin saw infinite changes taking place in nature evoking infinite responses in organisms (species) only the fittest of which survived. 
The differences between the theories of Lamarck and Darwin, illustrates vividly the difference between philosophical musings, even though they might be surprisingly intuitive and close to the heart of the problem, and a rigorous investigation based on observation supported by consistent data.
Yet what we often forget, in our bedazzlement at Darwin’s brilliance, is that Lamarck’s idea  that organisms responded to changes in their environment was transcendental  and was [probably] instrumental in the  formulation of Darwin’s theory of evolution.
   


 

Offline rosalind dna

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But Charles Darwin's grandfather Erasmus was one of his main
influences as was Frances Galton who believed in Eugenics.
http://en.wikipedia.org/wiki/Erasmus_Darwin
Galton was Charles' half-second cousin by marriage, I think.
http://en.wikipedia.org/wiki/Francis_Galton
 

Offline graham.d

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It is true that all new theories depend heavily on the amassed knowledge from others. In the case of Darwin and Lamarck, this was also probably true but that Darwin's ideas were much more subtle and difficult for people to understand. This leads to it being easy to misrepresent Darwin's ideas and then to destroy the resulting "Straw man". Even the phrase "survival of the fittest" is a simplification that can lead to much misunderstanding.
 

Offline McQueen

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It was not my intention to paint Darwin as a "straw man" ! Far from it, his genius and dedication to pure science are too well known for even an attempt to be made at denigrating him. However, what I am trying to bring to your notice, is the motive principle, Lamarcks's remarks if you will,that catalysed the whole theory.
 

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