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Deep phylogeny, ancestral groups and the four ages of life

Abstract:
Organismal phylogeny depends on cell division, stasis, mutational divergence, cell mergers (by sex or symbiogenesis), lateral gene transfer and death. The tree of life is a useful metaphor for organismal genealogical history provided we recognize that branches sometimes fuse. Hennigian cladistics emphasizes only lineage splitting, ignoring most other major phylogenetic processes. Though methodologically useful it has been conceptually confusing and harmed taxonomy, especially in mistakenly opposing ancestral (paraphyletic) taxa. The history of life involved about 10 really major innovations in cell structure. In membrane topology, there were five successive kinds of cell: (i) negibacteria, with two bounding membranes, (ii) unibacteria, with one bounding and no integral membranes, (iii) eukaryotes with endomembranes and mitochondria, (iv) plants with chloroplasts and (v) finally, chromists with plastids inside the rough endoplasmic reticulum. Membrane chemistry divides negibacteria into the more advanced Glycobacteria (e.g. Cyanobacteria and Proteobacteria) with outer membrane lipolysaccharide and primitive Eobacteria without lipopolysaccharide (deserving intenser study). It also divides unibacteria into posibacteria, ancestors of eukaryotes, and archaebacteria - the sisters (not ancestors) of eukaryotes and the youngest bacterial phylum. Anaerobic eobacteria, oxygenic cyanobacteria, desiccation-resistant posibacteria and finally neomura (eukaryotes plus archaebacteria) successively transformed Earth. Accidents and organizational constraints are as important and adaptiveness in body plan evolution.
Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1098/rstb.2009.0161

Authors

More by this author
Institution:
University of Oxford
Division:
MPLS
Department:
Zoology
Role:
Author


Publisher:
Royal Society Publishing
Journal:
Philosophical Transactions of the Royal Society B More from this journal
Volume:
365
Issue:
1537
Pages:
111-132
Publication date:
2010-01-01
Edition:
Publisher's version
DOI:
EISSN:
1471-2970
ISSN:
0962-8436


Language:
English
Keywords:
Subjects:
UUID:
uuid:f4d5f99c-7dcc-4196-b50f-f38839b185ab
Local pid:
ora:3491
Deposit date:
2010-03-10
ARK identifier:

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