Question: What is Darwin's theory of the origin of species?

Sarah Martin answered on 19 Jun 2012:

Hi meg!

Darwin published his book with his evidence for evolution in 1859. It was called On the Origin of Species. By the 1870s the scientific community and much of the general public had accepted evolution as a fact. The theory goes that all animals – and humans are also animals – originated and evolved from a common ancestor (we know now that this was approximately 3.7 billion years ago).
Looking at the shapes, biochemistry and DNA sequences, we can tell which animals are related closest, because these traits and sequences are more similar among species that share a more recent common ancestor. They can be used to reconstruct evolutionary histories, using both existing species and the fossil record.
After dropping out of a medical degree in Edinburgh (my university!) because he was much more interested in nature than in diseases, Darwin traveled for five years around the world on HMS Beagle and was puzzled about all the different animals and fossils that one can find in different parts of the world – in particular on the Galapagos islands – and this is what got him started on working on his theory!

🙂
Sarah