![]() Whether or not a trait is favorable depends on the environmental conditions at the time. ![]() The cheetahs’ fast speed is an adaptation for catching prey. ![]() The snow leopards’ thick fur is an adaptation for living in the cold. The webbed feet of platypuses are an adaptation for swimming. Scientists describe groups of organisms becoming adapted to their environment when a change in the range of genetic variation occurs over time that increases or maintains the “fit” of the population to its environment. Sexual reproduction also leads to genetic diversity: when two parents reproduce, unique combinations of alleles assemble to produce the unique genotypes and thus phenotypes in each of the offspring.Ī heritable trait that helps the survival and reproduction of an organism in its present environment is called an adaptation. Mutations may also have a whole range of effect sizes on the fitness of the organism that expresses them in their phenotype, from a small effect to a great effect. And, many mutations will also have no effect on the fitness of the phenotype these are called neutral mutations. A mutation may produce a phenotype with a beneficial effect on fitness. A mutation affects the phenotype of the organism in a way that gives it reduced fitness-lower likelihood of survival or fewer offspring. The genetic changes caused by mutation can have one of three outcomes on the phenotype. Mutation, a change in DNA, is the ultimate source of new alleles, or new genetic variation in any population. Genetic diversity in a population comes from two main mechanisms: mutation and sexual reproduction. This is critical because variation among individuals can be caused by non-genetic reasons such as an individual being taller because of better nutrition rather than different genes. Importantly, these differences must have some genetic basis otherwise, the selection will not lead to change in the next generation. Natural selection can only take place if there is variation, or differences, among individuals in a population.
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