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It's very possible that life arose independently multiple times, but one group grew fast enough to drive all the others to extinction. The life forms we observe
by kmicklas 12y ago
It's very possible that life arose independently multiple times, but one group grew fast enough to drive all the others to extinction. The life forms we observe now almost certainly came from one ancestor due to the numerous molecular similarities (e.g. use of the same form of DNA).
- NickNameNick 12y agoThat ignores the possibility that early forms of life combined to form fitter symbiotic life forms. The parallel that comes to mind is the mitochondria within animal cells, they probably originated as independent bacteria.