'Aliens Are Out There - And They Look Like Us'

Aliens resembling humans must have evolved on other planets, a leading biologist has claimed.

Evolutionary biologist Simon Conway Morris says it is surprising we have not already discovered extra-terrestrials that look like us - given the growing number of Earth-like planets now discovered by astronomers.

He based his claim on evidence that different species will independently develop similar features which means that life similar to that on Earth would also develop on equivalent planets.

The theory, known as convergence, says evolution is a predictable process which follows a rigid set of rules.

"I would argue that in any habitable zone that doesn't boil or freeze, intelligent life is going to emerge, because intelligence is convergent," he said.

"One can say with reasonable confidence that the likelihood of something analogous to a human evolving is really pretty high.

"And given the number of potential planets that we now have good reason to think exist, even if the dice only come up the right way every one in 100 throws, that still leads to a very large number of intelligences scattered around, that are likely to be similar to us."

The argument is put forward in his new book The Runes Of Evolution.

He has previously claimed that aliens would resemble earthlings with limbs, heads, and bodies.

And he goes further in the new book, claiming any Earth-like planet should also evolve predators like sharks as well as mangroves, and mushrooms, among many other things.