Natural selection that occurs when individuals with intermediate phenotypes are more fit is called
The correct answer and explanation is:
The correct answer is stabilizing selection.
Stabilizing selection is a type of natural selection where individuals with intermediate phenotypes (traits that are in the middle of the spectrum) have higher fitness compared to individuals with extreme phenotypes. This process tends to reduce the variation of a particular trait within a population because the individuals that are most adapted to their environment are those with traits that are closest to the average. In other words, both extremes of a phenotype are selected against, favoring individuals that have moderate, intermediate traits.
For example, in a population of birds where the beak size is important for feeding, stabilizing selection might occur if the environment favors birds with medium-sized beaks that are optimal for eating available food sources. Birds with very small or very large beaks might struggle to find food and survive, leading to a decrease in their numbers over time. The birds with intermediate-sized beaks, on the other hand, are better suited for the environment, and their traits are passed on more frequently to future generations.
This type of selection helps to maintain a balanced population where extreme traits do not dominate. It reduces genetic diversity in the short term by favoring average phenotypes but can also stabilize the population by keeping it well-suited to its environment. Over many generations, stabilizing selection leads to a narrower range of phenotypes in the population, ensuring that the traits that provide the best chance of survival continue to be passed down.