What is Life?

Are prions life according to that definition?

The prevailing theory of prion replication involves "autocatalytic protein misfolding." Why wouldn't that fall within your definition of "life"?Recent research also shows that, although they lack nucleic acids, prions undergo Darwinian evolution, including mutation and natural selection. That finding is irrelevant to your definition, but it would appear to bolster the case for considering prions to be a form of life -- at least in the same sense that viruses could be consider a form of life.Edited by Stephen Push, : No reason given.

Darwinian Evolution of Prions in Cell Culture. Science, 12 February 2010: 869-872.That page also contains links to two critical responses to the research paper and a rebuttal from one of the paper's authors. Although the requirement of synthesis in your definition excludes prions, why isn't the method by which prions replicate themselves a form of reproduction? Life is any chemical entity that replicates itself and evolves by means of mutation and natural selection.ORLife is any entity composed of organic molecules that replicates itself.Assuming the prion evolution theory holds up, I would prefer the first definition, since it would have the advantage of admitting extraterrestrial life that may not be based on organic chemistry. Edited by Stephen Push, : No reason given.