BIOL 1202 Lecture Notes - Lecture 3: Fortymile River, Gene Pool, Allele Frequency
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* remember that evolution is the change in gene frequencies in the population (unit that evolves). * population is a localized group of individuals that belong to the same biological species. (mutation is meaningful if it reproduces or if there"s a selective pressure) * populations are the smallest relevant evolutionary unit. Evolution acts only on heritable traits (mutation that evolve) Populations show variations (because of heritable differences or environmental differences) Some variation is the result of heritable changes (rise from mutation and/or genetic recombination - like the crossing over in mitosis, sexual reproduction) and some variations is nonheritable (see fig 23. 3) (environmental cause: got darker skin) Population of the same organism can show variations. This population variation can often be geographic (evolutionary important). The variation between populations can be discrete or continual. Ex) porcupine herd and fortymile herd & ranges overlap. * frequently continual variation in a population will exist as a cline (see fig 23. 5)