ENV100Y5 Lecture 12: ENV100 - 12 - Evolution Biodiversity and Population Ecology II
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Life is diverse how did it get that way: natural selection: traits that enhance survival and reproduction persist in populations, populations evolve over time, populations may diverge and form new species. Darwin"s dangerous ideas: evolutionary change by descent with modification, natural selection produces adaptations. Evolution: change in the genetic composition of a population. Genetic variation: mutations = accidental changes in dna that may be passed on to offspring; provide the genetic variation on which selection acts, mutation in myostatin gene produced double muscling in belgian blue cattle. Natural selection: individuals vary (different genotypes, not all individuals will survive to reproduce, success is usually not random, parents pass traits on to offspring. Only natural selection produces adaptations unrelated, but similar = convergent evolution. There are many ways in which a population can evolve, but only natural selection can produce adaptations. Drift is a random disappearance of certain alleles from the population.
