Breakthrough gives insight into early complex life on Earth

Japanese team spent 12 years on the project after digging up deep-sea mud

For the first 2 billion years, life on Earth comprised two microbial kingdoms - bacteria and archaea. They featured an innumerable and diverse variety of species, but, ultimately, life on Earth was not that exciting judged by today's standards.

Then, the theory goes, a rogue archaeon gobbled up a bacterium to create an entirely new type of cell that would go on to form the basis of all complex life on Earth, from plants to humans.