Biology 122 Exam 2 Study Guide

Biology 122 Exam 2 Study Guide - Biology 122 Exam 2 Study...

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Biology 122 Exam 2 Study Guide Sexual dimorphism: males and females show distinctly different appearance Secondary sexual characteristics: males and females have different physical characteristics which are not directly associated with reproduction or survival Sexual selection: a form of natural selection which individuals with certain characteristics are more likely to obtain mates Intrasexual selection: involves characteristics, which affect the outcome of competition among members of one sex for access Intersexual selection: influences the evolution of secondary sexual characteristics, which determine the relative attractiveness of members of one sex to the other sex Good genes hypothesis: females choose the males who are flashiest because it shows he must have good genes that allow him to overcome handicaps and avoid being eaten by predators Hierarchy of classification : each species is classified within a nested hierarchy reflecting the evolutionary diversification of life Kingdom, Phylum, Class, Order, Family, Genus, Species KPCOFGS King Phillip Comes Over For Good Sex The biological species concept: a population or group of population whose members can interbreed and produce fertile offspring traditional definition of species Morphological species concept : classifies organisms based on observable phenotypic traits Ecological species concept : defines a species by its ecological role Phylogenetic species concept : defines a species as a set of organisms representing a specific evolutionary lineage Speciation : the splitting of evolutionary lineages during the formation of biological species Allopatric speciation o Populations of the same species are geographically separated, separating their gene pools o Changes in the allele frequencies of each population may be caused by natural selection, genetic drift, and mutation, unaffected by gene flow from other populations o Gene flow between populations is initially prevented by a geographic barrier o 1. Single interbreeding population o 2. Population is divided by a barrier; subpopulations are isolated o 3. The two populations evolve independently, diverge in their traits o 4. Geographic barrier is no longer present, yet the two populations do not interbreed o the likelihood of allopatric speciation increases when a population is small and isolated small population may have a different gene pool due to the founder effect genetic drift and natural selection may have a greater effect in a small population in a new habitat
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sympatric speciation o new species may arise within the same geographic area as a parent species reproductive barriers o keep species separate by isolating a species gene pool and preventing interbreeding prezygotic temporal isolation o species breed at different times (seasonally) habitat isolation o species breed at different places and do not come in contact with each other behavioral isolation o there is little or no sexual attraction between species due to
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Biology 122 Exam 2 Study Guide - Biology 122 Exam 2 Study...

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