Looking for the origin of the Eukaryotes.
[sciencythoughts.blogspot.com]
The Eukaryotic cell is strikingly distinct from its much simpler Prokaryote relatives, possessing not only a nucleus, but also a complex cytoskeleton, a sophisticated endomembrane system, and mitochondria, the last of these the result of an ancient endosymbiosis with a Proteobacterium. How this complex cell evolved has long been a puzzle, in part because of the lack of living intermediate taxa that would help determine the sequence in which these distinctive Eukaryotic characters appeared. The recent discovery of the Asgard Archaea, a group closely related to eukaryotes that possesses homologues of several Eukaryote genes, has heightened interest in this problem, as they represent, in a sense, the transitional forms that have long been sought. Nonetheless, there will always be evolutionary transitions that cannot be inferred using modern taxa, as is well illustrated by the Birds, whose evolutionary history would be a mystery without the rich fossil record of the Dinosaurs. The fossil record of early Eukaryotes traditionally has been dismissed as useless for reconstructing Eukaryogenesis, in part because the important transitions involve characters which are typically not preserved (e.g. the nucleus, mitochondria, cytoskeleton), and in part because the prevailing view of early Eukaryote evolution assumes these transitions took place long before the first Eukaryotes show up in the fossil record.
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1 comment
Feel free to reply to any comment by clicking the "Reply" button.I find it interesting to think of some random atoms and molecules bouncing around in some ocean thermal vent: got together to begin a chemical process that causes the chemical processes to reproduce its cell structure and buildup or collect all the other components that make up cells that now reproduce and evolve.
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