To begin with, it was a common theory that evolution did not exist, and in fact every separate species had been made by God. It was believed; God created man, frogs, birds etc and they did not have a common ancestor. Darwin however challenged this theory with his paper entitled; The Origin of Species and the Galapagos Islands were crucial in his doing so. However his paper caused much controversy.
In the Origin of Species, Darwin’s theory discusses how populations had evolved over the course of generations through a process of natural selection. This paper was written based on the evidence that he had accumulated on his voyage to the Galapagos Islands on HMS Beagle in 1831.
His theory was based on around a few basic points;
No two individuals are identical in a reproducing species – this is so that the gene pool is widened to give the greatest advantage to the offspring to receive favored genes for survival.
The variations between individuals give them different chances of survival. Therefore, if an individual is suited to the environment it will have a greater chance of survival and reproduction than an individual that doesn’t. Therefore the favorable genes will be passed on and the unfavorable will die out.
Variation is inherited from the parents.
This process will lead to better equipped populations being produced and possibly new species being evolved due to favorable gened individuals surviving more successfully.
The main basis of Darwin’s theory settles mainly with the Galapagos Finches. They are a group of very similar but different species of finch. The finches are all very similar in size, shape and color. The only real difference is the size and shape of their beaks.
Each island was geographically isolated from the others. On each island the finches had different food sources. The beaks had developed Dependant on the food source, whether it was adapting to picking out seeds from plants to the cracking of nuts.
Because the birds were so similar, only having alterations in their beaks, it led Darwin to believe that they must all have had the same common ancestor. However, over time, favorable genes had been selected for and had resulted in the different shapes of the beaks. Also because the islands were separated, there was no mating between the finches with the different beaks. This then proved that evolution was in fact a very plausible explanation.
The Origin of Species catapulted Darwin into the limelight and now the Galapagos Islands are always regarded as the home of evolution.