BSC 116 Midterm: Exam 1 Study Guide
16 Feb 2017
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Conditions on early earth made the origin of life possible: experiments stimulating possible early atmospheres have produced organic molecules from inorganic precursors. Amino acids, lipids, sugars, and nitrogenous bases have also been found in meteorites: amino acids and rna mucleotides polymerize when dripped onto hot sand, clay, or rock. Organic compounds can spontaneously assemble into protocells- membrane-bounded droplets that have some properties of cells: the first genetic material may have been self-replcating, catalytic rna. Early protocells containing such rna would have increased through natural selection. The absolute ages of fossils can be estimated by radiometric dating and other nethods: the fossil record shows how new groups of organisms can arise via the gradual modification of preexisting organisms. Great increase in diversity of animal forms: 500 mya = colonization of land by fungi, plants, and animals. The rise and fall of groups of organisms reflect differences in speciation and extinction rates.
