October 27, 2014 by locu5amoenu5
Is complex life rare in the cosmos? The idea that it could be rests on the observation that the existence of life like us – with large, energy hungry, complicated cells – may be contingent on a number of very specific and unlikely factors in the history of the Earth. Added together they suggest that places like this could be exceedingly unusual across the universe. As I’ve pointed out in a previous post, there are some potential flaws to such arguments, largely because of the ways in which we make post-hoc inferences.
"In other words, if mitochondria and complex cells are the later outcome of a parasitic infestation, their existence is perhaps not so unlikely – there was a strong incentive for those ancestral mitochondrial species to find hosts, and the rest is just natural selection."