The Earth is billions of years old and was once a very hostile place. Eventually, a single cell was formed that evolved and reproduced. What conditions produced this first life on Earth?
- Evolutionary Theory suggests that all forms of life evolved from one ancestor - the first cell.
- 4.5 billion years ago, conditions on Earth were similar to that of Venus, with very little oxygen.
- It is thought that hydrogen, methane and ammonia in the Earth's early atmosphere combined with the oceans to form a pre-biotic soup.
- Exposed to ultraviolet rays of the Sun, the pre-biotic soup reacted to form organic compounds such as DNA - the building blocks of life.
Charles Darwin, The Origin of Species (1859) – "All organic beings have descended from... one primordial form, into which life was breathed."
This theory of evolution – known as 'universal common descent' suggests that humans are not simply evolved from an ape like ancestor our heritage goes much further than that.