History of Life Through Time Essay
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1. The website <http://tolweb. org/Life_on_Earth/1> shows the basic phylogeny of the three main lineages of life forms. They are “Archaea,” “Eubacteria,” and “Eukaryotes. ” It also shows “Viruses” outside of the tree, with a question mark indicating that its place in the tree is undetermined, if it belongs in the tree at all. 2. This site attempts to show the two alternative phylogenies of the major lineages of life forms. The “archaea tree” distinguishes two variations of archaea, and shows that archaea are more closely related to eukaryotes than to eubacteria.
In the “eocyte tree,” archaea are not specified at all, but eukaryotes are shown as most closely related to crenarchaeota-eocytes, which was a derivation of archaea in the previous tree. 3. Viruses are not listed in these two phylogenies because they are not proven to be actual life forms. Where archaea, eubacteria and eukaryotes are classified as “life forms” due to their ability to transfer genes, viruses have not been determined to be living.
They are therefore not included on these two phylogenetic trees.
At the other website, <http://www. ucmp. berkeley. edu/alllife/eukaryotasy. html>, a detailed phylogeny of the Eukaryotes is provided. From this it is evident that Fungi are more closely related to Animalia than to Plantae. 5. Both sites show that the major life classifications are “Bacteria,” “Eukaryotes,” and “Archaea. ” The “Tree of Life” site shows the alternatives to how closely the lineages are related, giving two examples of how the three domains may be nested within each other instead of being derived equally.
The University of California site breaks down the systematics of each domain separately and more specifically, leaving the three domains as separate entities entirely.
History of Life Through Time. 2009. University of California Museum of Paleontology. 3 June 2009 <http://www. ucmp. berkeley. edu/exhibits/historyoflife. php>. Tree of Life Web Project. 1997. Life on Earth. Version 01 January 1997 (temporary). 3 June 2009 <http://tolweb. org/Life_on_Earth/1/1997. 01. 01> in The Tree of Life Web Project, <http://tolweb. org/>.