Evolution

The Legacy of Lamarck



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Jean-Baptiste Lamarck (1744 - 1829) died 30 years before Charles Darwin's Origin of Species was published. He made considerable contributions to biology and conchology, but no one paid much attention to his passing. His ultimate fame rests on his ideas about evolution, which have been discussed and tested over the generations. Lamarck's theory of evolution was not based on natural selection, but on his predecessor Erasmus Darwin's speculation that "all warm-blooded animals have arisen from one living filament... with the power of acquiring new parts." These new parts were a response to "needs" created by the demands of the environment.

In his Philosophie Zoologique (1809), Lamarck postulated that during its lifetime, an organism would acquire characteristics that were needed to optimize quality and length of life, and would pass those on to its offspring. For instance, a giraffe which was constantly reaching up to forage in trees would develop a longer neck from all that stretching, and its progeny would inherit that trait. According to Lamarck, the diversity within species was the result of adaptation to local conditions.

Charles Darwin believed that natural selection was the primary mechanism for the development of species, but also accepted the Lamarckian hypothesis as a supplementary possibility for explaining changes in species, naming it Pangenesis. In response to environmental stimulation, some cells would throw off microscopic particles which could travel to other cells and change them. Strange as this theory sounds, it has an interesting similarity to the use of retroviruses in gene therapy.

Neo-Lamarckism is a theory of inheritance maintaining that genetic changes can be influenced by environmental factors. Ivan Pavlov (1949 - 1936), the pioneer in conditioned response, was a Lamarckist. He claimed that in his work, each subsequent generation of dogs was easier to condition. In the 1920's, William McDougall at Harvard, who was opposed to behaviorism, did experiments attempting to prove that white rats could inherit maze-running ability.

Since 1988 scientists have been working to demonstrate that single-celled organisms can re-program their own DNA under certain conditions. Applying this principle to higher organisms is generally considered pseudoscience, but that may change. Contemporary scientists such as Dr. Bruce H. Lipton are promoting a new perspective on human biology which integrates the role of mind and spirit in genetic control. The body is not just a mechanical device, but a community of cells which are innately intelligent and work together to accommodate the wishes and intents of a central voice which we identify as mind and spirit. According to this theory, our perception and interpretations of the environment directly control genes through the process of epigenetic control.

It is possible that both Darwin and Lamarck had a piece of the truth, but both were limited in their scope and underestimated the complexity of living organisms. The whole truth remains shrouded in mystery, waiting to be unveiled.



Sources and resources:
http://www.usp.nus.edu.sg/victorian/science/lamarck1.html

http://en.wikipedia.org/wiki/Lamarckism

http://findarticles.com/p/articles/mi_g2699/is_0005/ai_2699000543
William McDougall

http://www.brucelipton.com/article/mind-over-genes-the-new-biology
article by Bruce Lipton

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