A History of Ideas essay comparing and contrasting the theories of Lamarck and Charles Darwin (2008)

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1 A History of Ideas essay comparing and contrasting the theories of Lamarck and Charles Darwin (2008) Ben Moore Compare and contrast the evolutionary theories of Lamarck and Charles Darwin, with regard to their details, the sources of their ideas, and the historical circumstances out of which each arose. Are the differences between the two theories important? Explain why, or why not. Support your judgments with appropriate historical and biographical evidence. Charles Robert Darwin and Jean Baptiste Lamarck were two of the most influential theorists, when it comes to the progression of the theory of evolution, as we know it today. While both lived during some of the same time in the 19 th century and their theories had definite similarities, there are also some small differences which are very important because of the major ways in which they set the two views apart. It s important to understand these differences, as well as the difference in historical context when comparing and contrasting the two. Lamarck was a French biologist, who lived during the mid 18 th to early 19 th centuries ( ). His theory (or Lamarckism, as it is known) centered around the notion that living creatures inherited characteristics from their ancestors as well as the environment around them. A trait that was gained throughout an organism s lifetime (possibly even including instinctual behaviour), that allowed it to adapt to environmental obstacles or came about due to other forms of physical exertion, could be passed onto the future generations of the species. Other traits that aren t as necessary to the survival of that creature may also be lessened in future generations (Clifford, 2004, p2). A common example of this would be the Giraffe; Lamarck would have argued that to reach the leaves high up in the trees, the

2 Giraffe s neck muscles would ve have strengthened and lengthened, which it then passed onto its offspring (providing that both parents had gone through similar changes). Each generation would have a slightly longer and stronger neck and organs that it didn t use so much (such as the Giraffe s leg muscles), would become less pronounced. This would occur until the creature reached the peak of its development and became perfectly adapted to its surroundings. His theory also explained how over long periods of time, creatures could diverge far enough apart to become completely different species, however he did not believe in extinction. Instead he believed that species that disappeared had done so because they evolved into new species (UCMP, 2008, p4). This was widely regarded as the way transformationism (which was the term for evolution at the time) worked. In fact Charles Darwin s grandfather, Erasmus Darwin had also been a proponent of Lamarckism as well as Robert Edmund Grant, a professor of Charles at the University of Edinburgh. Darwin on the other hand was an English naturalist and geologist in the 19 th century ( ). His theory of evolution was similar in the way that traits of a species could be passed down from one generation to the next. However his theory (Darwinism as it was later labeled) was not derived from the idea of one s environment simply shaping their genetic abilities but from chance mutations and his concept of natural selection, which was a term he introduced in his book The Origin of Species in Natural selection comes from a range of observations that Darwin made but stems from the a few key ideas, such as; slight variations between creatures of the same species can give an advantage or disadvantage to that creature to survive. Groups of individual s competing for the same limited food source, may not all be able to get their required share and therefore the ones who have the characteristics that allow them to get the food easier will have a higher chance of survival and reproduction, therefore a higher chance of passing these traits along to their offspring to continue the trend. This slowly results in changes to the general population of a species and like Lamarck s theory, these changes will eventually accumulate to form new species (Darwin, 1859, Ch 14).

3 So even though Lamarckism has since been widely disproven by further scientific research and testing, particularly the perception that instinctual behavior can be passed on, there are still certain elements of it that hold true. Particularly those, that are common to both Darwinism and Lamarckism such as the gradual changes to a species over the generations leading to an increasing divergence and eventually entirely new species. But it is the differences more than the similarities that are important. Darwin s theory for instance explained how species could become extinct; something that Lamarck s did not. It is mentioned in his biography Darwin that "Darwin was loathe to let go of the notion that a well used and strengthened organ could be inherited" but even though he may have had some initial struggles with letting go of certain Lamarckian ideas, the fact that he trusted his evidence that pointed to the contrary is important (Desmond and Moore, 1991, p617). As mentioned Lamarckism was a widely believed view at the time and many of Darwin s influences were advocates of the theory. For Darwinism to challenge these views was no small task. So much so, that upon completing his theory, he would restrain from publishing it until two decades later. This was partially due to the Darwin s crisis of faith during these years. In his younger years, Darwin attended both the Church of England and Cambridge to become a clergyman and was a believer of William Paley s argument that theoretically proved the existence of God (Desmond and Moore, 1991, p47 48). Observations from his journey aboard the Beagle were key in questioning his faith and if his theories of natural selection were in fact correct it would go against not only his own beliefs but those of the majority of the general population as well as the Church, which had strong ties to the government at the time. Considerations, regarding when to make his theorising public for fear of scientific discreditation would have also been a strong factor in the delay of the Origin of Species, which was finally published in 1859 because of competition from Russel Wallace, a naturalist who had came up with an almost identical theory (Desmond and Moore, 1991, p ).

4 In contrast, Lamarck s theories were published in his book Philosophie Zoologique in 1809, approximately thirty years before Darwin had secretly comprised the main elements of his theory of evolution and fifty years before it would be published. It seems that Lamarck didn t have the same problem that Darwin did, regarding the delay of publication of his works. There are several possibilities as to why this may have been; Darwin felt the need to back up his theorising with copious amounts of proof and perhaps Lamarck felt he had more than enough evidence already or his theory was strong enough to speak for itself. Lamarckism was radical for its time but when compared to natural selection, probably not as big a leap over previous theories. Despite the fact that it seems they were unfamiliar with each other s work, natural philosopher Erasmus Darwin was already postulating that all organic life arose from tiny organisms (UCMP, 2008, p4). In his book Zoönomia ( ), Erasmus Darwin wrote would it be too bold to imagine that, in the great length of time since the earth began to exist, perhaps millions of ages before the commencement of the history of mankind that all warm blooded animals have arisen from one living filament, which the great First Cause endued with animality, with the power of acquiring new parts and of delivering down these improvements by generation to its posterity, world without end! and this was a decade earlier than Lamarck s publication (Slotkin [quoting Erasmus Darwin], 1963, p218). However even if they were unaware of each other s work, it does go some way to showing the changing climate at the time, where religious views of creationism were so prevalent, evolution was at least becoming a more widely accepted thought. Lamarck was also already a distinguished biologist and had published several works around the turn of the century on the subject of invertebrates (a term coined by Lamarck) and perhaps the success of these books gave him reason to believe that Philosophie Zoologique would continue this success. While Charles Darwin s theory of natural selection is commonly still thought of as one of the corner stone s of modern day evolution and Lamarckism is basically considered to be an outdated theory, it s clear that they were both very important factors in the journey of scientific discovery of the theory of

5 evolution. Just as Lamarck was expanding on the theories of previous evolutionary theorists and Charles Darwin continued by expanding on Lamarck s ideas, we will no doubt continue this chain as future scientific discoveries allow us to learn even more about evolution. Both theories may have derived from very different circumstances historically and scientifically but we are in a new scientific age and perhaps the next breakthrough in evolution is just around the corner.

6 Bibliography Clifford, David 2004, Jean Baptiste Lamarck, Cambridge University Darwin, Charles 1859, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, London; modern reprint Charles Darwin, Julian Huxley (2003). The Origin of Species. online.org.uk/content/frameset?itemid=f373&viewtype=text&pageseq=477 Desmond, Adrian & Moore, James 1991, Darwin, London Slotkin, James Sydney 1963, Readings in Early Anthropology, Routledge UCMP 2008, Biography of Lamarck, University of California Museum of Paleontology, California