Final answer:
Both biotic and abiotic selection pressures can influence allele frequencies (d) in a population, leading to adaptive evolution. Biotic factors like predation, and abiotic factors such as temperature, can select for or against certain alleles, affecting survival and reproduction. The study of these changes is a key aspect of population genetics.
Step-by-step explanation:
Both biotic and abiotic selection pressures can influence allele frequencies in a genetically diverse population. Biotic factors such as predation, competition, and disease can affect which individuals survive and reproduce, hence passing on their alleles. Abiotic factors, including temperature, water availability, and salinity, can also impact survival and reproductive success. Both factors can lead to adaptive evolution, where beneficial alleles increase in frequency while deleterious alleles decrease, through mechanisms such as stabilizing, directional, and diversifying selection, as well as genetic drift, gene flow, and mutation.
Changes in allele frequencies that are identified in a population can shed light on how it is evolving. If a given allele confers a phenotype that allows an individual to better survive or reproduce, this allele will become more widespread through natural selection, leading to changes in the genetic makeup of the population. Population genetics is the study of how selective forces change the allele frequencies in a population over time, which can provide insights into the selective pressures acting on a population.