A evolução primeva da fotossíntese
Early Evolution of Photosynthesis1
Robert E. Blankenship*
+ Author Affiliations
Departments of Biology and Chemistry, Washington University, St. Louis, Missouri 63130
*E-mail blankenship@wustl.edu.
doi: http://dx.doi.org/10.1104/pp.110.161687
Plant Physiology October 2010 vol. 154 no. 2 434-438
Photosynthesis is the
only significant solar energy storage process on Earth and is the source
of all of our food and most of our energy resources. An understanding
of the origin and evolution of photosynthesis is therefore of
substantial interest, as it may help to explain inefficiencies in the
process and point the way to attempts to improve various aspects for
agricultural and energy applications.
A wealth of evidence
indicates that photosynthesis is an ancient process that originated not
long after the origin of life and has evolved via a complex path to
produce the distribution of types of photosynthetic organisms and
metabolisms that are found today (Blankenship, 2002; Björn and
Govindjee, 2009). Figure 1 shows an evolutionary tree of life based on
small-subunit rRNA analysis. Of the three domains of life, Bacteria,
Archaea, and Eukarya, chlorophyll-based photosynthesis has only been
found in the bacterial and eukaryotic domains. The ability to do
photosynthesis is widely distributed throughout the bacterial domain in
six different phyla, with no apparent pattern of evolution.
Photosynthetic phyla include the cyanobacteria, proteobacteria (purple
bacteria), green sulfur bacteria (GSB), firmicutes (heliobacteria),
filamentous anoxygenic phototrophs (FAPs, also often called the green
nonsulfur bacteria), and acidobacteria (Raymond, 2008). In some cases
(cyanobacteria and GSB), essentially all members of the phylum are
phototrop2hic, while in the others, in particular the proteobacteria,
the vast majority of species are not phototrophic.
+++++
+++++
Nenhum comentário:
Postar um comentário
Observação: somente um membro deste blog pode postar um comentário.