BIOL 102 Lecture Notes - Lecture 7: Species Problem, Reproductive Isolation, Microevolution
25 Jan 2017
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Document Summary
Speciation- the origin of new species, is at the focal point of evolutionary theory. The origin of species : evolutionary theory must explain how new species originate and how populations evolve. Microevolution- changes in allele frequency in a population over time. Macroevolution- broad patterns of evolutionary change above the species level, by the same mechanisms that cause microevolution. The biological species concept emphasizes reproductive isolation. Species is a latin word meaning kind or appearance . Biologists compare morphology, physiology, biochemistry, and dna sequences when grouping organisms. Biological species concept states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring: they do not breed successfully with members of other populations. Gene flow between populations of the same species holds a species together genetically. Reproductive isolation- the existence of biological factors (barriers) that impede two species from producing viable, fertile offspring. Hybrids- offspring of crosses between different species.
