BIOL 4141 Chapter : Giarla Diversification Mammology 2014
Document Summary
From speciation to diversi cation: speciation is the link between microevolution (e. g. , population genetics) and macroevolution (e. g. , patterns of diversi cation and extinction) Examples: plants, sh, lizards, and the cambrian explosion. Adaptive radiations: an adaptive radiation is when rapid speciation in a single lineage is followed by divergence into many different adaptive forms. African rift lake cichlids: divergence due to: Why do adaptive radiations occur: two general mechanisms can trigger adaptive radiations, ecological opportunity, morphological innovation. Ecological opportunity as a trigger: similar adaptive radiations took place independently, triggered by the available environment and lack of competition. Morphological innovation as a trigger: flowers are a unique reproductive structure that are particularly ef cient at attracting pollinators, making angiosperms more reproductively ef cient. What triggered the cambrian explosion: there are four non-mutually-exclusive hypotheses: Crocidura shrews: hundreds of species, little ecological differentiation. The (gamma) statistic describes the shape of diversi cation.
