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In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing theoretical work by those such as Sewall Wright. As a result of the loss of genetic variation, the new population may be distinctively different, both genotypically and phenotypically, from the parent population from which it is derived. In extreme cases, the founder effect is thought to lead to the speciation and subsequent evolution of new species. In the figure shown, the original population has nearly equal numbers of blue and red individuals. The three smaller founder populations show that one or the other color may predominate (founder effect), due to random sampling of the original population. A population bottleneck may also cause a founder effect, though it is not strictly a new population. The founder effect occurs when a small group of migrants that is not genetically representative of the population from which they came establish in a new area. In addition to founder effects, the new population is often a very small population, so shows increased sensitivity to genetic drift, an increase in inbreeding, and relatively low genetic variation. Problems: Soon after the island of Hawaii rose above the sea surface (somewhat less than one million years ago), the evolution of life on this new island should have been most strongly influenced by _____. A) habitat differentiation B) a genetic bottleneck C) the founder effect D) sexual selection A population of organisms will not evolve if _____. A) the population size is large B) all individual variation is due only to environmental factors C) the environment is changing at a relatively slow rate D) the population lives in a habitat without competing species present #phyliogeneticTree #Evolution #speciation #diagram #branchingInAPhylogeneticTree #Genetics #bilology #taxonomy #cladogram #populationGenetics #hawaiiIslands #founderEffect #geneticDrift #geneticVariation
