Which situation is an example of diversifying selection?
In the ever-evolving world of biology and ecology, the concept of diversifying selection plays a crucial role in shaping the genetic diversity of populations. Diversifying selection refers to a type of natural selection that favors the maintenance of genetic variation within a population. This process occurs when different environments or ecological niches within a species’ range exert selective pressures that favor different traits. In this article, we will explore a specific situation that exemplifies diversifying selection and discuss its implications for the survival and adaptation of species.
The case of the peppered moth (Biston betularia) during the industrial revolution in England serves as a classic example of diversifying selection. Prior to the industrial revolution, the peppered moth exhibited a predominantly light-colored form, which was well-camouflaged against the light-colored trees and lichen in its natural habitat. However, as industrialization led to increased pollution and soot accumulation on trees, the dark form of the moth became more advantageous. This is because the dark form provided better camouflage against the now soot-covered trees, making it less susceptible to predation by birds.
As a result, the frequency of the dark form of the peppered moth increased within the polluted areas, while the light form remained prevalent in cleaner, less-polluted regions. This shift in allele frequencies exemplifies diversifying selection, as the selective pressures from the changing environment favored the evolution of a trait (dark coloration) that was previously less common in the population.
The peppered moth case study highlights the dynamic nature of natural selection and the importance of genetic diversity. Diversifying selection ensures that populations are equipped to adapt to changing environmental conditions. In the absence of diversifying selection, populations may become more homogeneous, making them more vulnerable to environmental stressors and less capable of withstanding ecological changes.
Furthermore, diversifying selection can also be observed in other situations, such as the adaptation of animals to different food sources or habitats. For instance, in a population of birds with varying beak sizes, a diversifying selection may occur if certain food sources become more abundant in one habitat while others become scarce. Birds with beaks well-suited for accessing the new food source will have a higher chance of survival and reproduction, thus increasing the frequency of that specific beak size within the population.
In conclusion, the peppered moth case study and other examples demonstrate that diversifying selection is a critical process in maintaining genetic diversity within populations. By favoring the maintenance of different traits, diversifying selection enables species to adapt to changing environments and enhances their chances of survival. Understanding the mechanisms and implications of diversifying selection is essential for conservation efforts and the study of evolutionary biology.
