The almost-certainty of ET being out there means that something does not add up, and badly. We should not be alone, but we are.
- Simon Conway Morris
Extra-terrestrials that resemble humans should have evolved on other, Earth-like planets, making it increasingly paradoxical that we still appear to be alone in the universe, the author of a new study on convergent evolution has claimed.
The argument is one of several that emerge from The Runes Of Evolution, a new book in which the leading evolutionary biologist, Professor Simon Conway Morris, makes the case for a ubiquitous “map of life” that governs the way in which all living things develop.
It builds on the established principle of convergent evolution, a widely-supported theory – although one still disputed by some biologists – that different species will independently evolve similar features.
Conway Morris argues that convergence is not just common, but everywhere, and that it has governed every aspect of life’s development on Earth. Proteins, eyes, limbs, intelligence, tool-making – even our capacity to experience orgasms – are, he argues, inevitable once life emerges.
The book claims that evolution is therefore far from random, but a predictable process that operates according to a fairly rigid set of rules.
If that is the case, then it follows that life similar to that on Earth would also develop in the right conditions on other, equivalent planets. Given the growing number of Earth-like planets of which astronomers are now aware, it is increasingly extraordinary that aliens that look and behave something like us have not been found, he suggests.
“Convergence is one of the best arguments for Darwinian adaptation, but its sheer ubiquity has not been appreciated,” said Professor Conway Morris, who is a Fellow at St John’s College, University of Cambridge.
“Often, research into convergence is accompanied by exclamations of surprise, describing it as uncanny, remarkable and astonishing. In fact it is everywhere, and that is a remarkable indication that evolution is far from a random process. And if the outcomes of evolution are at least broadly predictable, then what applies on Earth will apply across the Milky Way, and beyond.”
Read the full story
Image: The camera eye of an octopus is structurally similar to that of a human, but has evolved independently, making it a classic example of convergent evolution.
Credit: Albert Kok, via Flickr.
Reproduced courtesy of the University of Cambridge
______________________________________________