Happy Birthday Darwin!

Posted: February 12, 2012 by Mr Bilton in Animals, Biology, Discoveries, Scientists
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Happy birthday to you, happy birthday to you, happy birthday dear Charles Darwin, happy birthday to you!

Happy Birthday Darwin!

On this day in 1809 Charles Darwin, arguably one of the most important scientists ever, was born in Shropshire. Charles Darwin is famous for his book On the Origin of the Species where he introduced ideas to explain the origin and diversity of all living species via Natural Selection and Evolution. Darwin was interested in most things, and his work as a geologist and naturalist gave him to opportunity to travel around the world on a 5-year voyage aboard the ship HMS Beagle. Keeping careful notes and making copious observations during the expedition, Darwin saw great biodiversity and it allowed to him to begin considering the origin of this. When he returned to England he began to formulate his idea of Natural Selection.

HMS Beagle

What is Natural Selection?

Darwin had noted that nearly all the species he had encountered were perfectly adapted to a variety of different habitats, diets and lifestyles. His visit to the Galapagos Islands (near Ecuador) had allowed him to study a group of birds (now known as Darwin’s Finches). He was amazed at the variety of different beak shapes and sizes, each adapted to a different way of life.

The Galapagos Islands

How did this happen? Natural selection requires three factors. The first is variation (differences) between individuals. The second is competition between organisms (e.g. not enough food to feed every organism) and finally an environmental change.

Darwin postulated that originally a group of finches arrived at the Galapagos islands from mainland Ecuador. There was variation of beak size within this group of finches. Because there were different food sources on the island (seeds, fruit, insects etc) different beak sizes were more suitable for different diets. For example, large beaks would be able to break open seeds that smaller beaks wouldn’t. If there were plentiful seeds, the larger beaked birds would find more food, have more offspring and therefore pass on the genes for the larger beak. This would continue as long as larger beaks gave a survival advantage. Eventually, with successive generations and continued ‘selection’ for a certain feature, the original population of birds diversified into many different species.

Darwin's Finches

Darwin realised that this same process, occuring over millions of years, could explain the diversity of all living (and extinct) species.

The Theory of Evolution has shaped our understanding of diversity, formation of new species and our position in the Tree of Life. So, thanks Darwin, and Happy Birthday!

The Tree of Life

 

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