BIO120H1 Study Guide - Final Guide: Rusty Crayfish, Alloenzyme, Cellulose Acetate
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BIO120H1 Full Course Notes
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Rusty crayfish: introduced, negative impact on natives (outcompete for food, shelter) Allozyme electrophoresis: rusty crayfish can mate and form hybrids with natives. Find allozyme loci where species fixed for different alleles, homozygous. Sampled crayfish from area where both species occurred. Found individuals heterozygous at these loci, species could mate and form hybrids. Genetic variation necessary for evolution of adaptations by natural selection. All organisms face stresses (natural sources, human impact); environment variable. If individuals genetically similar, equally susceptible to stresses; populations must be able to adapt to changing environments. Adaptive potential is basis for natural selection, genetically determined. In order for species to survive, some populations must exhibit sufficient genetic variation to adapt to changing environment. Widespread loss of genetic diversity in great lakes fishery populations. Overexploitation and invasion has placed stress on native fish species, many commercially valuable species eliminated or reduced. Sources of stress of human origin, favour particular individuals, reduce overall diversity.
