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Principles of Taxonomy: Prokaryotic Organisms

Analyze the paper by Urakawa et al. (2012) by considering the characteristics that allow us to classify the prokaryotic organisms in this study as belonging to different domains. Use the website: http://www.ucmp.berkeley.edu/exhibit/phylogeny.html

Review the definitions of Archaea and ammonia-oxidizing bacteria. Begin at http://www.ucmp.berkeley.edu/exhibit/phylogeny.html, webpage titled "Welcome to the Phylogeny Wing. Select the link "Phylogeny of Life" within the first of the "four ways to get started." Look at the relationship between DNA and the Three Domains of Life.

1. What general characteristics determine whether a prokaryote belongs to the Archaea or Bacteria domain?

2. Define DNA and RNA. What role do DNA and RNA play in this determination?

3. What role does the metabolism play in classifying Nitrosococcus oceani and Nitrosopumilus maritimus as Archaea or Bacteria?

4. Do either of these organisms normally thrive in an environment where crude oil is abundant? What other microbes live in this type of environment?

Solution Preview

1. There are three domains of life on Earth. The domains are Archaea, Bacteria, and Eukaryote that was classified by American microbiologist and physicist Carl Woese in 1990. The three domains of life were classified based on the differences in their 16S rRNA genes. The Prokaryotes was divided into Archaea and Bacteria because neither of them are ancestors of each other.

Archaea Domain are prokaryotic cells that are characterized by membranes that are branched hydrocarbon chains attached to glycerol by ether linkages. The presence of this ether containing linkages in Archaea adds to their ability of withstanding extreme temperature and highly acidic conditions. For examples, the extreme halophies are part of the Archaei that thrive in highly salty environment, and the hyperthermophiles. These organisms thrive in extremely hot environment, which is the best examples of Archaea.

The Bacteria Domain have bacteria species that belong to the prokaryotic cells. Bacteria are different from Archae because some bacteria ( Cyanobacteria and mycoplasmas) do not have ether containing linkages like Archaea. Because of this, they are group into the bacteria domain and not Archae. There is a great deal of diversity in this domain and it is impossible to determine how many species of bacteria exist on the planet.

The unique characteristics that distinguish archaea from bacteria are that Archaea evolved from earliest cells and they inhabit only very extreme environments. There are only few hundred species that exist. The bacteria are modern prokaryotes that evolve more ...

Solution Summary

This response looks at how prokaryotic organisms are classified and belong in different domains of life.

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