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How difficult is the transition to multi-cellular life?
I've done some more reading on this topic, and it really does appear that the emergence of eukaryotic life was a unique event. I think its safe to say that such a transition is unlikely to be repeated in most biospheres. Heres a quote from William F Browns book. Perspectives: The Evolution of the Cosmos, Life, Humans, Culture and Religion.

"The evidence that the beginning of eukaryotic cells was a singular event with a common ancestor is twofold. First, eukaryotes share many strutural similarities not found in bacteria or archaea. Second, among the five major families derived from the common ancestral group of eukaryotic cells, their common heritage is spelled out in the many similarities in their genomes, especially for those genes that encode key eukarytic proteins.The big mystery surrounding the emergence of eukaryotes is why it took so long for a common eukaryotic ancestor to emerge. "

"After all, for close to two billion years the earth was populated by bacteria and archaea, and at no time during that long period or since then has either domain shown any evidence of evolving intermediate steps towards eukaryotes, such as the development of an enclosed nucleus or any of the membranous cytoplasmic inclusions so characteristic of all eukaryotic cells. Nick Lane suggests one reasons may be that bacteria and archaea possess some fundamental constraint which somehow blocked the development of further complexity - except once, when one, and only one common ancestral eukaryote possibly emerged in four billion years of life on earth."

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RE: How difficult is the transition to multi-cellular life? - by Avalancheon - 06-25-2018, 06:45 AM

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