BIL 160 Lecture 9: Chapter 24: The Origin of Species
12 Feb 2017
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Start memorizing table 25. 1, p. 527 geological time scale (major boundaries between eras correspond to major extinction events in the fossil record. ) Microevolution: evolutionary change within a species or population. A change in allele frequencies in a population over generations. Three main mechanisms cause allele frequency change. Only natural selection consistently causes adaptive evolution; cannot fashion perfect organisms. Selection can act only on existing variations. Chance, natural selections, and the environment interact. In the galapagos islands darwin discovered plants and animals found nowhere else in the world. Speciation: the origin of new species, is at the focal point of evolutionary theory. Evolutionary theory must explain how new species and how populations evolve. Microevolution: evolution within a species and populations. Macroevolution: broad patterns of evolutionary change about the species level. Species is a latin word meaning kind or appearance . Biologists compare morphology, physiology, biochemistry and others to define species.
