Jean-Bauptiste Lamarck, a French naturalist, is arguably one of the most notable figures whose theories helped Darwin's famous theory of evolution. Lamarck believed that the changes in the environment caused changes in the species behavior which caused a change in a species characteristics as a result of needing to adapt to their environment in order to survive, these traits were then passed down to the offspring to continue the survival of the species. Even though we now know that genetics do not work the way Lamarck theorized, his theory which laid the ground work for Darwin's own theory. While Lamarck's theories are discredited and even mocked by Darwin and other anthropologists, Darwin admitted that Lamarcks theory of use and disuse (in that certain organs are rendered nonfunctional due to not aiding in the animals survival) did help Darwin in his own theory and was even shown plausible in the case of moles. According to Uucmp.berkeley.edu and Darwin "the vestigial eyes of moles and of cave-dwelling animals are "probably due to gradual reduction from disuse, but aided perhaps by natural selection.""
Darwin's theory is that animals with the traits better suited for their environment would have the likelier chance of surviving, such that the chances of having the more suitable traits is random and most often (except for in the case of humans) uncontrollable. It is this theory that was shaped by Lamarck's, albeit wrong, theory of evolution. He believed, as illustrated by the Introduction to Physical Anthropology text book, that the long neck of the giraffe was due to the giraffe's need to reach leaves (food) higher up in the trees. He believed that this change in the neck length was due to the giraffe stretching its neck higher as needed, and the trait passing on through reproduction. Lamarcks theory supports the idea that survival is only possible through evolution and the changes in species are transmitted through reproduction as Darwin believes but genetics has shown that traits that change after birth do not pass on in this way. Darwin, having a better understanding of genetics, adapted this theory in that species born with the more favorable variation of traits to suit their environment are more likely to have better access to the resources, a better chance at surviving and a better chance at reproducing or passing on those more favorable traits.
Darwin, or any other theorist could not have built their theories on their own. Science is a building of knowledge upon prior knowledge, be it rejecting, accepting or adding on to or even retesting that prior knowledge. It is because of the nature of science and the scientific method that Darwin could not have developed his theories on his for he had to have had prior knowledge to build upon-be it the rejected theory of Lamarck that species can change their own characteristics to survive as well as pass them on, or the expanded upon theory that animals evolve to survive in their changing environments, or even the acceptance of the theory that organ can be rendered not functional if they have gone unused for a prolonged amount to time.
Darwin was hesitant on releasing his book, On the Origins of Species, because the Reform Movement in Britain had taken head, during which many radicals like atheists (who favored and supported theorists like Lamarck) had started to speak out against the church. Thus evolution had become synonymous with atheism. With this perception attached to his work, Darwin feared publishing his work to the Church dominated public could cause backlash towards him and his family as well as receive harsh reactions from the Church. His wife was also quite religious which caused strife between them. However, Darwin had written to another theorist, Alfred Russel Wallace, and feared that if he did not publish then, Wallace could steal Darwin's ideas and pass them off as his own. A year later, Darwin published his longest surviving piece to date, On the Origins of Species.
In general, good discussion of Lamarck's work, with just a couple of comments:
ReplyDeleteI'm curious about your emphasis on the word "species" in your opening section. Lamarck didn't consider evolution happening at the species level but at the level of the individual (which represents a key difference from Darwin, who argued that evolution acted at the level of the population).
Second, the information you cite at the end regarding vestigial organs is not a situation where Lamarck was right. Darwin was only considering the possibility but we know now that the loss of those organs is the result of natural selection. Some current researchers have discovered situations where, at the cellular level, processes similar to the issue of use/disuse may appear to occur in relation to epigenetics, but this would be on a very limited basis in specific situations.
http://www.technologyreview.com/news/411880/a-comeback-for-lamarckian-evolution/
Good discussion of the points you can tie to Lamarck's work. Very thorough and well-explained.
" Darwin, or any other theorist could not have built their theories on their own. "
I agree with this when considering the scientific community as a whole, but we are asking about Lamarck specifically here. Lamarck is important as the first to propose an actual mechanism of evolution but he was certainly not the only scientist to explore the idea of evolution. Darwin had many influences in this way... so how crucial was Lamarck on his own?
For your last section, to be clear, the church was opposed to the concept of evolution long before the Reform movement, so I'm not sure how much the tie with atheism comes into play here (a source for this information would have been helpful). I suggest the church would have given Darwin trouble even without this historical circumstance. That said, good job pointing out the issue of Darwin's wife and her strong faith, and the concerns Darwin would have had as to how she would have been impacted. You are also right to note that Darwin was concerned with the backlash against his family in general. A scientist doesn't work in a bubble. He/she is influenced by not just scientific issues but personal issues as well. Could Darwin have been concerned about the impact on his professional career as well?
Good post.