Many people think of evolution when they think of the Galapagos Islands. This is because of Charles Darwin's famous voyage to the islands in 1835 where he developed his theory of evolution and natural selection. Though Darwin is well known for the theory of evolution, he did not create the theory. The idea of evolution was invented long before Darwin was born; he conducted the research necessary to determine evolution had actually occurred and release the information to the public. Darwin learned about a theory called “Transformism” while he was at Cambridge. Transformism was a theory very similar to evolution developed by Jean Baptiste de Lamarck, who believed organisms evolved because of their environment; the main difference between the two theories was when they believed the organisms evolved. Lamarck believed animals evolved during their lifetime, unlike Darwin who thought they evolved through generations. Darwin did not believe in theories like transformism until he observed the organisms in the Galapagos. Darwin’s observations of the Finches on the islands led to the improvement of the theory of evolution.
Darwin's Finches
Over Darwin’s five weeks on the islands, he observed the finches he saw on the islands and compared them to the mainland finches he observed earlier in his voyage. The finches on the mainland were nearly identical to the finches on the islands, except for their different beaks; unlike the mainland finches, the finches on the islands had to adapt to the food sources on the islands. The isolation of the island finches allowed them to undergo speciation, which caused them to develop different features than the mainland finches. While in the Galapagos, Darwin observed 14 different organisms that he concluded were 14 different species of birds. 12 of these species had never been seen before, and Darwin inferred that they were specific to the Galapagos Islands.
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| Darwin's Finches John Gould |
Natural Selection
Natural selection is a large part of the theory of evolution. The concept of natural selection is an old philosophy that Darwin added to with the information from his observations in the Galapagos Islands. Natural selection preserves minor mutations of organisms that give that specific organism an advantage in their environment. The organism with the original mutation passes the trait on to their offspring, who then pass it on to their offspring, giving this group of organisms an advantage over the others. The organisms with the mutation are stronger than those without, so the organisms without the mutation will eventually die off. Once the organisms without the mutation die off, the only members of the species left are those who have evolved. Natural selection allows species to grow stronger and survive in their environment by eliminating weaker traits in organisms over time.
How do you feel the theory of evolution has affected our knowledge of the past or our predictions for the future? Do you think future discoveries will help confirm or destroy the theory? Why do you think there have always been such strong doubts about the theory of evolution?
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I think something that is interesting relating to the theory is human height. There is such a range in height right now from 4ft to over 6ft. There doesn't seem to be a more dominant height. If the birds that developed stronger beaks survived and now there is one sole bird type of beak... what will happen with humans to make a shorter person or a taller person the people that survive? Also it could be that we already have been through natural selection and the range of heights that people are in have already been narrowed down into the heights that most people are today. If that is not the case and we haven't been through natural selection yet, will humans destroy this theory?
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