Which is the best definition of directional selection? a process by which two species can no longer reproduce a process by which one of the extreme variations of a trait is favored a process by which individuals with either extreme of a trait are favored a process by which average individuals in a population are favored
The Correct Answer and Explanation is:
The best definition of directional selection is: a process by which one of the extreme variations of a trait is favored.
Explanation:
Directional selection is one of the mechanisms of natural selection where individuals with traits at one extreme of the phenotype distribution are more likely to survive and reproduce. This form of selection typically occurs when environmental conditions change, and one particular trait variation provides a survival advantage over others. Over time, this causes a shift in the population’s overall phenotype distribution in the direction of the favored trait.
For example, in a population of birds, if the environment changes in such a way that only birds with longer beaks can access food, birds with shorter beaks may struggle to survive. In this case, the birds with longer beaks represent the extreme variation that is now favored, and the population will gradually shift towards having longer beaks as the trait becomes more common in successive generations.
This type of selection contrasts with stabilizing selection (where the average phenotype is favored) and disruptive selection (where both extreme phenotypes are favored). Directional selection can be observed in various species, from finches with different beak sizes to antibiotic resistance in bacteria.
In short, directional selection results in a population that is increasingly adapted to its environment, with one extreme of a trait becoming more common over time.
