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Year 5 Science


Charles Darwin (1809–1882)

darwin

Charles Darwin was born in Shrewsbury, where his father was a doctor. When he studied at Cambridge, he became interested in all of the different species of plants and animals that we see in nature. He wanted to understand why such variety of life existed. Aged 22, he was invited to sail to South America, working as a naturalist on the ship HMS Beagle. For five years he sailed the world and collected samples of rocks and animals, just as he had loved collecting shells when he was a little boy. He found many rocks containing fossils of things that had lived millions of years ago but had become extinct.

Out in the Pacific Ocean, far from the South American coast, the Beagle reached the Galapagos Islands. Darwin found finches and tortoises there. There were six species of finches, similar except for their beaks. Some birds had big, powerful beaks and others were thinner and sharper, but with gradual steps from thinnest to thickest like half-sizes in a shoe shop. Darwin considered whether one species from long ago had gradually separated into several different forms. He discovered that different species, each with its own characteristics, had evolved from a shared ancestor. Now they are called Darwin’s finches.

darwin finches

Darwin explored the different islands of the Galapagos, and he found that the tortoises were gigantic, but they were not all the same. On some hot islands they had long necks for feeding on tall, spiky cactus plants. The tortoises even had a notch in their shells that let them stretch higher. On cooler islands, there was plenty of grass to eat at ground level and the tortoises had short necks. It suggested to Darwin that the tortoises had slowly adapted to suit the islands’ different habitats. The different species of giant tortoises of the Galapagos all shared a common parent many generations back, but this original species of tortoise evolved to have different characteristics in the different habitats of the different islands.

When he came home, Darwin spent several years sorting out his ideas. Only when another scientist, Alfred Russel Wallace, described some similar ideas did Darwin publish his great book On the Origin of Species by Means of Natural Selection. ‘Natural selection’ was his term for the idea that animals and plants best suited to their environment are more likely to survive and reproduce. Other people call it ‘survival of the fittest’. The book is central to our understanding of the theory of evolution. It took many years for people to accept the idea. Some did not like the thought that we shared common ancestors with apes.

With so many facts to support it, Darwin’s theory was gradually accepted. He joined the Royal Society and was eventually honoured with a burial in Westminster Abbey, very near to Isaac Newton. On the Origin of Species is his most famous work but he never stopped writing, even in old age.

This activity is adapted from pages 336-337 of What Your Year 5 Child Needs to Know, which can be purchased here.