01:119:115 Lecture Notes - Lecture 21: Species Problem, Species, Allopatric Speciation
2 May 2016
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Document Summary
Evolutionary theory must explain how the populations evolve (last chapter) and how new species originate. Microevolution changes in allele frequency in a population over time. Macroevolution broad patterns of evolutionary change above the species level. Speciation= process by which one specie splits into o2 or more spp yielded tremendous diversity of life. ~10 and 100 million species exist today new spp that result share many characteristics b/c descended from common ancestor: the concept of biological species based on reproductive isolation. Group of populations whose members can interbreed in nature and produce viable, fertile offspring. Do not exchange genes with different species reproductively isolated. Reproductive isolation mechanisms to prevent two species from interbreeding and producing viable, fertile offspring. Different types of reproductive barriers fertilization: prezygotic isolation mechanisms. Ex: 2 species of garter snakes in same area but one terrestrial / one aquatic: temporal isolation: breed at different times can be different times of year, season, or of day.
