The Evolution Theory: Lamarck vs. Darwin - Essay Example

The Evolution Theory: Lamarck vs. Darwin Jean Baptiste Lamarck was among the earliest researchers to develop the theory of evolution. According to his observations in the said field, every organism was believed to have adapted to its environment, which took place over a long period of time. These adaptations were mainly related to the way the organisms used their various parts of the body. He put forth the theory that those body parts of the organisms that were used less frequently or that were never used at all to help them survive in their environment would not be needed in future.

This, according to him, is the Law of Use and Disuse. This theory of evolution was supported through the inheritance of acquired characteristics. This aspect was, however, challenged in the coming years with the discovery of the fact that genes are passed on from one generation to the next, which meant that his initial theory was rendered baseless, as the characteristics of an organism is provided by its genes which are not subject to change within the life of the organism. Although the body cells might change but that does not warrant the fact that the sex cells would change too.

In order to prove this theory, an experiment was conducted whereby the tails of some mice were cut off but their offsprings had a tail when they were born. Similarly in the case of giraffes, who lived in dry regions where the leaves are high and they had to stretch their necks to eat those leaves. The stretching of necks over a period of time, led their necks to stretch and grow and the same was then passed on to their offsprings, meaning thereby, that all the future generations of giraffes shall have long necks.

Charles Darwin, on the other hand, was of the opinion that there are innumerable kinds of species and this very fact, of the differences among the species allowed some of them to be more adaptable / successful than the others in a given environment. He labeled this phenomenon as natural selection. Hence any change in their natural environment would lead them to adapt to it and only those who could adapt to such changes would flourish. This theory is more popularly known as “survival of the fittest”.

Thus according to Darwin’s theory only those species / organisms that had the ability to adapt to their changing environment and escaping their predators were able to survive. Continuing with the same example of giraffes, Darwin was of the view that giraffes had shorter necks initially, in fact, the size of the necks of each giraffe was different from the other and only those who had longer necks could reach the high leaves, thus they were able to get more food compared to those with shorter necks.

This however meant that those giraffes who had taller necks were able to survive better than those with comparatively shorter necks and could not reach the high leaves. Hence the giraffes with shorter necks perished due to want of food and those with longer necks produced more offspring and passed on the gene responsible of the length of the neck to their offsprings as well. This took several generations to transform and did not happen overnight. In conclusion, both Darwin as well as Lamarck the physical changes in the giraffes, did not happen overnight rather it took place gradually, over a period of time through several generations.

However they do differ on their opinions regarding the changes in the physical characteristics whereby, Lamarck propagates the theory that the changes took place with “all” the organisms of the same species, but Darwin was of the opinion that only those organisms that were able to adapt to the changing environment were subject to such changes. Also they both differ on one more significant aspect of the theory, that is, Lamarck believed that the organisms themselves attempt to change according to the environment whereas Darwin believed that the environment led to the changes and the organisms had no role to play in facilitating the change themselves.

The circumstance of the changing environment gradually led to such change. REFERENCES Understanding evolution, June 8th, 2008. Available from: