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Unformatted text preview: 50% evolution ecology Review • If evolution can be defined as changes in allele frequencies , then the ultimate form of evolutionary change is extinction • An example of pre-adaptation is dinosaur scales becoming feathers • Biological species concept – gene flow must be homogeneous • Reproductive isolation – hybrid sterility (horse and donkey) o Odd number can not undergo meosis o Plants can instantaneously double number of chromosomes (sympatric speciation) Instead of 3+2 doubles and becomes 10 (poly ploidy) o Allopatric – geographic isolation • Punctuated equilibrium times of stability followed by rapid change etc • Gradual – slowly changes • Evolutionary novelties (hair lots of speciation from that) • Extinction – competitors, predators and parasites • Gravitational theory – • Cell theory – Population Ecology • Dispersion • Changes in population sizes population models • Population regulating mechanisms • Reproductive strategies r & K selection • Survivorship curves Ecology—Recommended reading • Population ecology o Chap 51 • Community ecology o Chap 52 Dispersion – spacing of population populations changing not static • Clumped (patchy) o Most common where resources are partitioned in certain areas and animals will be clumped around them • Uniform o Each one has it’s own territory • Random o Resources are spread out Changes in population size – malfus population will continue to grow if resources are unlimited •...
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