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Unformatted text preview: Jesse Vella (jav2138) Environmental Microbiology P.S. #1 1. Describe different criteria based on which organisms can be classified, along with their associated limitations? Taxonomy, the science of classification, uses two primary techniques to distinguish between organisms. Examining a cells phenotype and morphology, its observable properties, metabolism, function and appearance, is one technique. Another adopted method, made available through recent technological breakthroughs, is phylogeny. It is a classification technique that investigates differences in microorganisms based on genetic information encoded in DNA. Proper classification uses a combination of both taxonomy and phylogeny, because each practice has limitations. Taxonomy is mostly superficial, using physical attributes for identification, although the process documents chemical reactions catalyzed or caused by specific organisms. Phylogeny is restrictive based on the technology used to differentiate genetic strands. Another limitation arises because of the exchange of genetic information that occurs between species existing in similar environmental media. This further complicates the setting of boundaries to distinguish organism types. 2. What are some distinguishing features between the three divisions of life? There exist three principal dominions that contain all organisms. Prokaryotes are contained under the Bacteria and the Archaea dominions, while all complex plants and animals, along with algae and protozoa, are classified as Eukarya. Prokaryotes are single-celled organisms that do not contain their genetic coding (chromosomes) inside a nucleus. Eukaryas chromosomes are contained within the nucleus, whether it is single or multi- cellular. A major distinguishing factor between Bacteria and Archaea is that Archaea are capable of producing methane gas via methanogenesis. Bacteria and Archaea differ also in their cell wall composition, consistency of membrane lipids, and RNA polymerase type and structure....
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- Spring '10