Geographic variation

Patterns Clinal traits change gradually across space latitude, altitude, temperature, vegetation ring population: the clines separate and then meet, the species are unable to mate where they meet because they changed across the clines → see [[migration models]] for ring species and isolation-by-distance Discrete clear geographic boundaries local adaptation with gene flow Mechanism that generate geographic variation [[selection|natural selection]] abiotic: temperature, precipitation, solar radiation, soil color biotic: predation, vegetation Bergmann's rule: larger in cold Allen's rule: shorter appendages in cold Gloger's rule: lighter in cold [[migration models|gene flow]] transfer of genetic material from one population to another local scale: homogenizing force, opposing divergence continental scale: clinal variation, isolation by distance [[genetic drift]] random allele frequency changes; amplified in small or isolated populations plasticity a single genotype produces different phenotypes in response to environment conditions

Types of geographic variation