File:Cavalier-Smith - The tree of life and major steps in cell evolution.png

From RationalWiki
Jump to navigation Jump to search

Original file(600 × 1,007 pixels, file size: 388 KB, MIME type: image/png)

This file is from Wikimedia Commons and may be used by other projects. The description on its file description page there is shown below.

This tree diagram image could be re-created using vector graphics as an SVG file. This has several advantages; see Commons:Media for cleanup for more information. If an SVG form of this image is available, please upload it and afterwards replace this template with {{vector version available|new image name}}.


It is recommended to name the SVG file “Cavalier-Smith - The tree of life and major steps in cell evolution.svg”—then the template Vector version available (or Vva) does not need the new image name parameter.
Description
English: The tree of life and major steps in cell evolution. Archaebacteria are sisters to eukaryotes and, contrary to widespread assumptions, the youngest bacterial phylum. This tree topology, coupled with extensive losses of posibacterial properties by the ancestral archaebacterium, explains (without lateral gene transfer) how eukaryotes possess a unique combination of properties now seen in archaebacteria, posibacteria and a-proteobacteria. Eukaryote origins in three stages indicated by asterisks probably immediately followed divergence of archaebacteria and eukaryote precursors from the ancestral neomuran. This ancestor arose from a stem actinobacterial posibacterium by a quantum evolutionary shake-up of bacterial organization - the neomuran revolution: surface N-linked glycoproteins replaced murein; ribosomes evolved the signal recognition particle’s translational arrest domain; histones replaced DNA gyrase, radically changing DNA replication, repair, and transcription enzymes. The eukaryote depicted is a hypothetical early stage after the origin of nucleus, mitochondrion, cilium, and microtubular skeleton but before distinct anterior and posterior cilia and centriolar and ciliary transformation (anterior cilium young, posterior old) evolved (probably in the cenancestral eukaryote). Kingdom Chromista was recently expanded to include not only the original groups Heterokonta, Cryptista and Haptophyta, but also Alveolata, Rhizaria and Heliozoa, making the name chromalveolates now unnecessary. Excavata now exclude Euglenozoa and comprise just three phyla: the ancestrally aerobic Percolozoa and Loukozoa and the ancestrally anaerobic Metamonada (e.g. Giardia, Trichomonas), which evolved from an aerobic Malawimonas-related loukozoan. Sterols and phosphatidylinositol (PI) probably evolved in the ancestral stem actinobacterium but the ancestral hyperthermophilic archaebacterium lost them when isoprenoid ethers replaced acyl ester lipids.
Date
Source doi:10.1186/1745-6150-5-7
Author Thomas Cavalier-Smith
Permission
(Reusing this file)
w:en:Creative Commons
attribution
This file is licensed under the Creative Commons Attribution 2.0 Generic license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

Captions

Add a one-line explanation of what this file represents

Items portrayed in this file

depicts

February 2010

image/png

418c4348bb0d546fdb832516a0beb6f05abf858e

397,085 byte

1,007 pixel

600 pixel

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current21:24, 2 August 2015Thumbnail for version as of 21:24, 2 August 2015600 × 1,007 (388 KB)Kopiersperre{{Information |Description={{en|'''The tree of life and major steps in cell evolution.''' Archaebacteria are sisters to eukaryotes and, contrary to widespread assumptions, the youngest bacterial phylum [6,13]. This tree topology, coupled with extensive...

The following page uses this file:

Metadata