ANTHRBIO 201 1st Edition Lecture 9 Macroevolutionary processes Microevolution natural selection mutation migration genetic drift ^^ all 4 forces Macroevolution Questions: how are new species created? how do species change over time? Species concepts These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Similarities and differences between species Chimpanzees and gorillas physical similarities: no tail behavior similarities: knucklewalkers, intergroup aggression difference: use of tools, small/large body size, small/large size of body parts (brain, testis) species are real but no real agreement in biological world about definition Biological species groups of potentially or actually interbreeding organisms that are reproductively isolated from others emphasis on reproductive isolation to create barrier gene flow homogenizes populations idea that places a premium on reproductive isolation Ecological species groups of organisms created and maintained through the process of natural selection selection maintains species boundaries despite gene flow Allopatric speciationA definition geographic isolation between two or more population of a single species leads them to diverge and form new species reproductive isolation between the 2 other evolutionary forces may accentuate differences character displacement a process that causes members of 2 species to diverge from each other due to the effects of competition IV. Sympatric speciationstrong selection that favors different phenotypes leads to speciation in the absence of geographic isolation Daphne Major deserted island in Galapagos Peter and Rosemary Grant measured every bird they captured Medium ground finch x cactus finch = big bird hybrid bird sings different song to attract matesdifferent modes of speciation allopatric (barrier of gene flow created by geographic isolation leads to 2 entirely different things) sympatric (barrier of gene flow isn’t necessary; process can occur at same place) rates of speciation dependent on number of available ecological niches niche= total range of conditions under which the population lives and reproduces mammalian radiation now is land of humans but used to be land of dinosaurs F.G.H.V. Adaptive radiations process where a single species diversifies to fill several open