What did Darwin see in nature?
As a child Charles Darwin was fascinated by the plants and animals around him and spent a great deal of his time looking at creatures and thinking about how they came to exist and why they looked and behaved the way they did.
As a young man in his twenties, Darwin visited many different countries where he came across exotic and unusual animals. On the Galapagos Islands he met up with giant tortoises. He noticed that several of the islands had their own separate species of tortoise (as well as finches, thrushes and plants). Some tortoise species were bigger than others, and some had special patterns or shapes to the shells. He even had a go at riding one or two! This is what he wrote in his diary about that … “I frequently got on their backs, and then giving a few raps on the hinder (back) part of their shells, they would rise up and walk away, but I found it very difficult to keep my balance.”
Why did Darwin become such a famous scientist?
Spotting the small differences between the tortoises and between other animal species, left Darwin wanting to know WHY they were different.
Darwin worked out that when living things reproduce, their offspring (that’s their babies) show differences (or variation). Perhaps one variation for a tortoise might be having a shell shaped to give more protection from predators! If a tortoise can protect itself better, it has a better chance of surviving and of having baby tortoises compared with other tortoises. That means in the next generation, there are likely to be more tortoises with shells that give them greater protection. This process is called Darwin’s theory of natural selection. Darwin chose the words ‘natural selection’ because when farmers and race-horse breeders select particular animals for breeding, it is called ‘artificial selection’ – so Darwin decided that this natural process of selection should be called ‘natural selection’.
Evolution – Darwin’s greatest idea
Darwin also worked out that over hundreds of thousands or even millions of years, populations of animals and plants (through natural selection) can change, or evolve, into completely different looking organisms. Darwin concluded that ALL the amazingly different types of living things we see on Earth, have come from simpler creatures from long ago. The time periods needed for evolution are ENORMOUS though – so don’t expect to see animals changing in front of you!