JMU BIO 150 Exam 2

JMU BIO 150 Exam 2 Define macroevolution ️evolutionary change above the species level, including the origin of a new group of organisms or a shift in the broad pattern of evolutionary changes over time How do we identify a species? ️groups of actually or potentially interbreeding populations that are reproductivley isolated from other such groups Define reproductive isolation ️cannot produce viable offspring Define viable ️offspring can reproduce Define speciation ️splitting event that creates two or more distinct species from a single ancestral group What are the three stages of specification? ️1. population separation 2. divergence 3. productive isolation preventing gene flow Define population separation ️isolation of gene pool Define divergence ️changes in gene pool (1 or both) What are the two types of separation of populations? ️-allopatric model -sympatric model Define allopatric model ️separation due to geographic isolation Define sympatric model ️separation due to competition or polylodisism in population What are the mechanisms of allopatric separation? ️-dispersal and colonization -vicariance Define dispersal and colonization ️-start with one continuous population -goes to an isolated area (island) -finishes with one population isolated from the other Define vicariance ️-start with one continuous population -landscape is changed -two populations are isolated from one another When does peripatric speciation occur? ️when one of the isolated populations have very few individuals What causes divergence of populations in sympatric speciation? ️-disruptive selection -polyplodism Define adaptive radiation ️the rapid diversification of a group of organisms into forms filling different ecological niches via sympatry Define niches ️role you fill in given environment What drives adaptive radiation? ️-opportunity -morphological innovations -sex How would you know if two species are productively isolated? ️- unsuccessfully interbreed -produce viable hybrids that are selected against What are the types of prezygotic barriers? ️-habit isolation