BIOSC 0160 Study Guide - Final Guide: Clematis, Pelagic Zone, Prokaryotic Small Ribosomal Subunit
24 Dec 2017
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22. 1: species are reproductively isolated lineages on the tree of life. Biologists approach the concept of species differently, depending on the focus of their research. The dobzansky-muller model explains how reproductive isolation results from the accumulation of genetic incompatibilities following a splitting of the ancestral population (interruption of gene flow) 22. 3: speciation may occur through geographic isolation or in sympatry. 22. 4: reproductive isolation is reinforced when diverging species come into contact. Natural selection does not directly favor the evolution of postzygotic isolating mechanisms, it"s a(cid:374) after-effect. Because individuals that breed with own species are more fit, avoiding interbreeding becomes favorable. Hybrid zones if reproductive isolate is incomplete, closely related species may hybridize in areas where their ranges overlap, resulting in the formation of a hybrid zone. 22. 5: speciation rates are highly variable across life. Speciation rates vary for different groups of organisms due to several ecological and behavioral factors.
