Module 20Order the major evolutionary events since the cooling of the earth’s crust Hadean- formation of earth, curst, and oceans, origins of cellular lifeArchaean- origins or anoxygenic, cyanobacteria, and oxygenic photosynthesisProterozoic- ozone shield formingPhanerozoic- extinction of dinosaursExplain how oxygen levels rose in the atmosphere; what is one type of geological evidence for this “great oxidation event” Oxygen levels rose in the atmosphere because organisms evolved the ability to use water as a source of electrons resulting in O2 accumulated in the atmosphere. Iron banding in rock formation is evidence of the “great oxidation event”What are microbial mats and stromatolites Microbial mats- microbial communityStromatolites- fossilized microbial matsDescribe how early bacteriology classification comparisons were done; what was the manual that was used Early bacteriology classification comparisons were done with staining/microscopy and biochemical test. The manual was used for gram – and gram +Justify why molecular sequences are best for determining phylogenetic relationships; what sequence is most commonly used Molecular sequences are best for determining phylogenetic relationships because it allows you compare organisms in an obvious way. The sequence most commonly used is 16S rRNA.Order the steps in isolating 16S rRNA genes by PCR and building a phylogenetic tree Isolate DNA, amplify 16S gene by PCR, run an agarose gel, sequence, align sequences (generation tree)Understand how sequence differences are used to construct a distance matrix and build a phylogenetic tree The tree is constructed with branches, nodes, and the length of the branches implies evolutionary distanceDefine fitness; provide an example of evolution and fitness that has been observed in recent years Fitness- the ability of an organism, with a given genotype or phenotype, to grow and reproduce,and to contribute its genetic information to future generations. An example would be antibiotic resistance.Distinguish a core genome and pan genome Core genome- all genes in commonPan genome- all genes in all organisms being comparedWhat is genetic drift and how has it been studied in E. coli populations Genetic drift is where the fraction of members of a population changes as a result of random sampling. It had been studied in E. Coil populations where cultures have been followed and sequenced for over 50,000 generations.Provide an example of how genetic drift takes place on the context of human health An example of how genetic drift takes place on the context of human health is infectious diseases.Explain how can comparative genomics reveal genes important for causing diseaseComparative genomics reveal genes are important for causing disease by closely showing genomes are constantly changing and
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