BIO 1130 Lecture Notes - Lecture 19: Australopithecus Afarensis, Homo Ergaster, Human Migration

• School: University of Ottawa
• Department: Biology
• Course: BIO 1130
• Professor: Jon Houseman

Document Summary

Lecture 19: chapter 7, geographic variation and speciation. One species, two populations of caribou: the individuals of each population have a tendency to mate with members of their own population. (positive assortative mating) Polymorphic species: species formed of several geographic groups which differ from each other by traits that are easy to recognize (sometimes called morphs, forms or subspecies) Ecogeographic rules: models of geographical variation that follows climatic gradients for many species within a group of vertebrates: (1) bergmann"s rule. In endothermic animals in general, the populations living in northern regions of the geographic distribution of the species will generally have a larger size. 72% of birds and 65%of mammals follow bergmann"s rule. Ex; hairy woodpecker: (2) allen"s rule: In birds and mammals, the northern populations (or species) will generally have short and massive extremities, whereas the southern populations (species) will have longer and thinner extremities. Ex; arctic fox, fennec fox: (3) gogler"s rule: