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In nature, populations are usually evolving. The grass in an open meadow, the wolves in a forest, and even the bacteria in a person's body are all natural populations. And all of these populations are likely to be evolving for at least some of their genes. Evolution is happening right here, right now! To be clear, that doesn't mean these populations are marching towards some final state of perfection. All evolution means is that a population is changing in its genetic makeup over generations. And the changes may be subtle—for instance, in a wolf population, there might be a shift in the frequency of a gene variant for black rather than gray fur. Sometimes, this type of change is due to natural selection. Other times, it comes from migration of new organisms into the population, or from random events—the evolutionary “luck of the draw.“ In this article, we'll examine what it means for a population evolve, see the (rarely met) set of conditions required for a population not to evolve, and explore how failure to meet these conditions does in fact lead to evolution. Problem: A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. 16) What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time? A) The genotype AA is lethal. B) There has been sexual selection favoring allele a. C) There has been a high rate of mutation of allele A to allele a. D) The two phenotypes are about equally adaptive under laboratory conditions. #HardyWeinbergLaw #population #alleleFrequencies #Mutation #genotypes #HardyWeinbergEquilibrium #populationGenetics #alleleFrequency #genePool #NikolaysGeneticsLessons #hardyWeinbergAssumptions #hardyWeinberg #Genetics #genotypeFrequencies #hardyWeinbergEquations #hardyWeinbergEquilibriumExplained #Genotype #educational #biology #cartoon #animation #tutorial #introduction #basics #overview #apBiology #hardyweinbergProblems
