Evolution is a theory stating living organisms have developed and diversified from earlier forms during the history of the earth. But how did scientists even come up with such a complex idea?
Charles Darwin, a naturalist in the 1800’s had a key role in the creation of the evolutionary theory. Darwin while aboard the ship the H.M.S Beagle (for five years) traveled the world collecting evidence that would later help to support his theory of evolution. The most influential place that Darwin gathered specimens from were the Galapagos Islands. At the Galapagos Darwin observed many different species such as the land and water iguanas, which were colored differently to improve the iguanas’ survival on either a marine or land environment. Darwin also observed tortoises whose shells varied depending on environment, finches who had different shaped beaks depending on the island they lived on, and many more. The most useful to his studies were the Galapagos finches. Darwin found, by capturing finches from the different islands, that their beaks were shaped according to the type of food available on each island. By realizing this key piece of information it contributed to Darwin’s idea of evolution, since the finches that survived on each island were those that could make the best use of the resources. Later Darwin would call this selection by nature of which organism would survive natural selection (also known as survival of the fittest). But why did organisms of the same species have different characteristics? This difference in species is now called variation, and it is the key to natural selection.
Variations are differences that are passed down from parents to offspring. One example of variation is how the rock pocket mouse develops dark or light fur color to help it blend in with dark rocks or light sand. These varying traits are the result of mutations is the DNA, and they can either improve or diminish an organism’s chance of survival. Variation is one of the reasons organisms evolve because the organisms most fit to their environment are