Exam 12: Microbial Evolution and Systematics

Because DNA:DNA hybridization reveals subtle differences in genes,it is useful for differentiating organisms from different

________ formed the semipermeable membrane-like surfaces for the earliest life forms.

Evolution is driven by

Why is the biological species concept useful for Eukarya but not meaningful for Archaea and Bacteria? How are prokaryotic species defined?

The early energy reactions used hydrogen,which is a powerful ________ and could have been used to form ________.

Rhodobacter cells perform photosynthesis in the presence of light and grow heterotrophically in the dark.After being cultured in total darkness for multiple generations phenotypic and genotypic changes occur.What phenotypic changes occur and what evolutionary processes are driving them?

Two tubes are inoculated from one test tube of a bacterial culture.The cultures are then transferred every day for 2 months.All of the media and growth conditions are the same in every tube.After 2 months of cultivation,the fitness and genotype frequencies of the populations in the two tubes are compared.The fitness of the two cultures is the same,but the genotype frequencies are very different in the two cultures.How is this possible?

Which statement most closely expresses our present understanding?

Sequencing technology and molecular phylogenetic analyses have had very little impact on our understanding of the evolution and diversity of life on Earth.

Draw a graph of relative fitness and number of mutations of an evolving strain versus the ancestral strain over 20,000 generations under the same growth conditions.Explain the change in fitness and mutations over time using evolutionary concepts and terms.

Two eukaryotic organelles that are hypothesized to be the result of endosymbiosis are the ________ and the ________.

The earliest RNA probably functioned in

You are studying 12 new isolates from the human skin.The isolates have 16S rRNA sequences that are 97% similar and share important phenotypic traits.Their genomes have 55% of their genes in common.The isolates would most likely be

Oxygen did not accumulate in the early atmosphere until it reacted with reduced materials,especially ________,in the oceans.

Life is believed to have originated at hydrothermal springs on the ocean floor rather than on near the surface of Earth.What conditions made the hydrothermal springs the likely place for the beginning of life? Relate the conditions of the early oceans to the likely metabolism of the first cells.

The evolutionary history of a group of organisms is called its ________ and it is inferred from ________.

Draw a rooted phylogenetic tree containing seven organisms labeled A to G.Label your tree with the following terms: branches,extant taxa,nodes,last common ancestor,and an outgroup.

The most widely used molecule in sequence-based evolutionary analyses are ________ genes.

All unicellular organisms belong to the same domain of life.

Explain the endosymbiotic theory.What is the evolutionary value of endosymbiosis?