StellarPhenotypic Variations and Fitness
Natural selection acts on phenotypic variations in populations, and these variations can significantly affect the survival and reproductive success of individuals in a given environment. The fitness of an organism—its ability to survive and reproduce—is influenced by its phenotype, which is determined by its genotype and the interaction with the environment. Phenotypic variations provide the raw material for natural selection to act upon, and environments often apply selective pressures that favor certain traits over others.
As environments change, the selective pressures on populations also change. This can lead to shifts in the traits that are advantageous, influencing which phenotypes become more or less common in the population over generations. For instance, flowering time in plants can be influenced by global climate change, with plants that bloom earlier or later in response to changing temperatures having different chances of successful reproduction. Similarly, the classic example of the peppered moth illustrates how changes in the environment—such as increased industrial pollution darkening tree trunks—can shift the selective pressures, favoring darker moths over lighter ones.