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Science

Theories of evolution

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Darwin's theory of evolution explains how life on Earth has changed over geological time. Scientists believe this is the reason why all living things on Earth exist today. The theory is supported by evidence from fossils, and by the rapid changes that can be seen to occur in microorganisms such as antibiotic-resistant bacteria. Many species have become extinct in the past and the extinction of species continues to happen.

Evolution timeline

The basic idea behind the theory of evolution is that different species have developed over time from simple life forms. These simple life forms first developed more than three billion years ago (as the Earth is believed to be about 4.5 billion years old).

This timeline shows key events in the evolution of life forms on Earth, from the first bacteria to the human species.

You can see a more detailed history of life timeline on BBC Nature.

Document

Download and print Tree of Life poster (pdf file, 2.6Mb)

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