Name: Susan C.
What characteristics make the
Archaea bacteria different enough from the rest of the bacteria to justify
placing them in a separate kingdom? Is it due to the diversity of
the group (cell wall and can stand extreme temperatures?).
The grouping of bacteria into clusters that should
represent evolutionary lineage is called phylogeny.
Phylogeny can be based on different data. Commonly
used is the sequence of the genes encoding the RNA
parts of ribosomes (the cellular particles responsible
for protein production). These RNA genes are highly
conserved, but vary significantly between the clusters
of the phylogenetic tree as we know them, including
the separation of archae with the other bacteria.
But other genes or other characteristics can also be
used for phylogeny, and it is reassuring to see that
the trees generated with different input data
frequently correlate with the RNA trees. That
indicates that we're on the right track. Though the
details of such trees often vary, and can be the
reason for serious debates, the position of the
archeans and the rest of the bacterial world is
generally not disputed.
If you are interested in bacterial phylogeny, or
taxonomy, have a look at a magnificant web site: the
Tree of Life. (http://tolweb.org/tree/) It also
includes the eukaryotes, including animals and plants.
It is a pleasure browsing in there.
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Update: June 2012