We are all familiar with the English naturalist Charles Darwin's famous book Evolution and impressed deeply by his opinion that all species of life in the world have descended from common ancestry by natural selection. This idea was put forward by Darwin according to his large amounts of detailed observations to different species after his 5 years travel around the world. But can you imagine that Galapagos tortoises have play a role in it? Let's see it.
On the 27th of December in 1831, Darwin started his historic voyage on the HMS Beagle. He went to many different places. During the five years' voyage, Darwin spent most time on land investigating geology and making species collections, at the same time he kept careful notes of what he observed.
HMS Beagle arrived at Galápagos islands in 1835. Marveling at the various animal life he found, he visited the islands for almost five weeks, searching for species collections. On the different geologically 13 islands, he found those giant tortoises slightly differing from island to island. In more professionally words to say, he found each of these Galápagos Islands had a tiny different subspecies of the giant tortoise. what's more to his surprise, each subspecies was uniquely fit for survival in that peculiar island environment. For instance, on island with lush pastures highlands domed shells tortoises were found; on island with arid areas tortoises who have longer legs and saddle-back shells were found. Because long legs will be a little convenient for them to climb to search food, while saddle-back shells can make them easier to reach bushes and cactus that grows high off the ground. Besides those two features, they are also smaller in size and physically need less food.
These similar difference about Galápagos tortoises appeared several times in his writings and journals, for example, " I have not as yet noticed by far...that the different islands to a considerable extent are inhabited by a different set of beings... They can distinguish the tortoises from the different islands; and that they differ not only in size, but in other characters...". These compelling evidence for evolution as well as other ones he collected during the journey played a role in the development of his theory of evolution. After another two years study and summary, he put forward his theory which is noted as one of the most greatest three discovery in 19th century.
For more information on the Galapagos Tortoise, you can check the information available online, and these will help a lot about Galapagos Tortoise.
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