Darwin's Lumpers Vs Splitters

The tree of life has many branches on it. The argument about how many branches it should have is between the lumpers and the splitters. Lumpers want fewer branches, and Splitters want more. Delineating the divisions is not clear cut. Morphology, anatomy, genetics, and other characteristics are difficult to tease apart.

Currently there is disagreement on where archea should be placed. The archea are generally described as a third division of life with the other two divisions being bacteria and eukaryotes. archea are prokaryotic like bacteria (meaning they do not have membrane bound nuclei) but have other characteristics similar to eukaryotes.

However some biologists think archea should be placed in a group that includes eukaryotes. Evidence about similarities in lipid (fat) synthesis support this placement. The terminology biologists use to describe this is "archea should be placed basally in a clade with all eukaryote organisms." This means that in the tree of life archea would be a twig sprouting near the base of the eukaryote branch. While compelling, this view has yet to be embraced by mainstream biology.


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