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Genetics The rate of evolutionary change in a population is proportional to the amount of genetic diversity available.

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Presentation on theme: "Genetics The rate of evolutionary change in a population is proportional to the amount of genetic diversity available."— Presentation transcript:

1 Genetics The rate of evolutionary change in a population is proportional to the amount of genetic diversity available.

2 Genetic variation has three levels: heterozygosity- genetic variation within individuals variation among individuals within a population variation among populations

3 Results of the loss of genetic diversity:  lower fitness- i.e. lifetime reproductive success relative to other individuals in the population  reduced evolutionary flexibility of populations

4 Causes of declines in genetic diversity: Founder effect- when a few individuals establish a new population, the genetic composition depends on the founders Demographic bottlenecks- occurs when a new population experiences a severe, temporary reduction of size Genetic drift- random change in gene frequencies in small populations. Through chance alone some alleles will not be represented in the next generation.

5 Genetic Diversity: Inbreeding inbreeding- mating with closely related individuals results: increased homozygosity inbreeding depression- reduced fecundity, offspring size, growth, or survivorship; changes in age of maturation and physical deformities

6 Loss of among-population genetic diversity: when historically divergent, isolated populations experience unusually high rates of gene flow…  organisms are moved  creation of new corridors

7 Management Concerns maintenance of viable populations in the short term maintenance of the ability to adapt maintenance of the ability for continued “natural” speciation

8 Populations deme- locally, randomly interbreeding group of individuals metapopulation- network of populations that have some degree of intermittent or regular gene flow among geographically distinct units. populations exist along a continuum


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