To start this blog off, a little bit of history.
Do you know who Charles Darwin is? How about Alfred Wallace? Jean-Baptiste Lamarck? You’ve probably heard of the first guy. The second, maybe. The third? Perhaps if you’re interested in biology, or French science.
All three men are important in the development of evolution by natural selection as an idea. Darwin is the most famous because of his grand work, Origin of Species, which contributed not just to evolutionary theory but also to the communication of science both then and now. But Wallace and Lamarck should not be forgotten; both have their place in the history of the evolutionary theory, and therefore, are important to the content of this blog. Here is a little summary:
Evolution was Charles Darwin’s idea wasn’t it? Not exactly. Darwin is really most famous for his work on natural selection, and his work, Origin, is correctly titled: On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (quite a title!). He was not the first to suggest that all animals have evolved from older forms and so evolution is not strictly his idea alone. The idea that all life was somehow linked is actually an ancient one: ancient Greeks and early Islamic scholars had some idea. By the 18th Century, naturalists such as Buffon, and Charles Darwin’s grandfather, Erasmus Darwin, were speculating on the idea that organisms had changed over time from older versions, that they had evolved. In the early 19th Century, Jean-Baptiste Lamarck, a French naturalist, put forward his own theory for how evolution works. Lamarckism, as it became known, proposed that organisms inherited changes caused by use or disuse in its parents. For example, if a parent giraffe stretches its neck to get at leaves on tall trees, its descendents are born with longer necks, and so giraffes evolve over generations to have long necks. While his theory was subsequently disproven, aspects of his idea still float around today, especially in the field of epigenetics, where, in addition to the inheritance of genetic code, alterations to a parent’s DNA and genome also may be inherited by subsequent generations. These include chemical alterations to the DNA and chromatin which can regulate the activity of genes. These alterations are responsive to environmental stimuli, which loosely makes them Lamarckian. However, these alterations are only passed down to offspring if they occur in the sperm and eggs of parents, and so they are not strictly characteristics that have changed as a the result of ‘use and disuse’ in parents as Lamarckism proposes.
So, evolution wasn’t Darwin’s idea, and Darwin wasn’t even the first to propose a theory of evolutionary change. Why, then, is Darwin famous and what was Darwin’s breakthrough?
Evolution by natural selection
“A struggle for life.”
Darwin noticed that organisms face competition: competition for resources, for mates, between species. Darwin saw that a natural selection of organisms was a result of this struggle, and meant the organisms which would compete better survived to have offspring. Darwin suggested that evolution of species was caused by this natural selection. However, though it seems this was an original idea by Darwin, a similar idea had been developed independently by another scientist, Alfred Wallace. His understanding of the geographical distribution of species was key in developing many of the speciation ideas that evolution by natural selection requires. His work included the Wallace Line, a boundary line described by Wallace that separates animal species in Asia and Australasia. In fact, Wallace’s work and his subsequent letters to Darwin explaining his ideas convinced Darwin to finally publish Origin. Darwin has gained fame from this book and today Wallace is a rather forgotten character, but at the time of publication, the work of both scientists was acknowledged. In 1958, a year before Origin was published, a joint reading of papers by the two men was presented to the Linnean Society – On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection (available in its entirety at the Alfred Russell Wallace Correspondance Project), the first communication of the theory of evolution by natural selection. Origin was Darwin’s completion of the work read out at the joint reading, and the ideas and evidence enclosed formed the foundation of evolutionary biology and are the basis of biology as a whole.
Darwin’s breakthrough was natural selection, and it is for his substantial body of diligent work in his book, Origin, which he is famous. But it is a great shame that today the world has pushed Wallace into the sidelines. Darwin’s book is the basis of biology but Wallace’s independent work spurred him to publish it and his contribution should not be forgotten.