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Deep phylogeny, ancestral groups and the four ages of life

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 em...

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Autor principal: Cavalier-Smith, Thomas
Formato: Texto
Lenguaje:English
Publicado: The Royal Society 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842702/
https://www.ncbi.nlm.nih.gov/pubmed/20008390
http://dx.doi.org/10.1098/rstb.2009.0161
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author Cavalier-Smith, Thomas
author_facet Cavalier-Smith, Thomas
author_sort Cavalier-Smith, Thomas
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description 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 internal 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 as adaptiveness in body plan evolution.
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spelling pubmed-28427022010-03-23 Deep phylogeny, ancestral groups and the four ages of life Cavalier-Smith, Thomas Philos Trans R Soc Lond B Biol Sci Articles 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 internal 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 as adaptiveness in body plan evolution. The Royal Society 2010-01-12 /pmc/articles/PMC2842702/ /pubmed/20008390 http://dx.doi.org/10.1098/rstb.2009.0161 Text en © 2010 The Royal Society http://creativecommons.org/licenses/by/2.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Articles
Cavalier-Smith, Thomas
Deep phylogeny, ancestral groups and the four ages of life
title Deep phylogeny, ancestral groups and the four ages of life
title_full Deep phylogeny, ancestral groups and the four ages of life
title_fullStr Deep phylogeny, ancestral groups and the four ages of life
title_full_unstemmed Deep phylogeny, ancestral groups and the four ages of life
title_short Deep phylogeny, ancestral groups and the four ages of life
title_sort deep phylogeny, ancestral groups and the four ages of life
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842702/
https://www.ncbi.nlm.nih.gov/pubmed/20008390
http://dx.doi.org/10.1098/rstb.2009.0161
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