Which of the following statements is CORRECT regarding models of adaptation that invoke allele-frequency adaptive landscapes? They assume that natural selection can either increase or decrease population mean fitness as long as there is no genetic dominance at any of the loci. O They assume that natural selection can only increase population mean fitness, which means that populations can get "stuck" on local peaks associated with lower fitness than the global optimum. We can assume that such landscapes have multiple peaks only when there is no epistasis for fitness among any of the loci under consideration.
The process by which living organism adapt and change is called natural selection. Variations exist among individuals, so the individuals that possess the most favorable traits are able to survive and reproduce in the changing environment than others. According to the theory given by Fisher's Fundamental Theorem of Natural selection, Natural selection can only increase the population mean fitness in a changing environment. Adaptive landscape depicts the mean fitness of a population but not the fitness of a genotype in a multidimensional space, similar to a mountain range. Such landscapes represent adaptive peaks and adaptive valleys. Allele combinations that differ in two or more genes show higher fitness than average allele combination. Populations have the ability to adapt and evolve with the changing environment because of natural selection. It can change the adaptive topography. So we can say that, natural selection is a hill-climbing process, where natural selection pushes population upward or towards higher fitness. If it is any mutation or genetic drift, it will result in adaptive valleys that is the population expands around the peaks.
Epistasis is a type of genetic interactions among any loci and their effect on fitness is an important evolutionary process because it can create adaptive peaks or multiple fitness peaks when there is genetic interaction among genetic loci.
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