Final answer:
The term 'descent with modification' refers to the changes in the genetic makeup of populations over time as a result of evolutionary forces, such as natural selection. It's closely related to, but not precisely represented by, the Hardy-Weinberg equilibrium equation p² + 2pq + q² = 1.
Step-by-step explanation:
The concept of descent with modification is one of the core principles of evolutionary biology. While there isn't a singular 'equation' for this concept, it ties closely to the Hardy-Weinberg equilibrium, an equation that indicates the genetic makeup of a non-evolving population. The equation is p² + 2pq + q² = 1, where p represents the frequency of the dominant allele and q represents the frequency of the recessive allele for a particular gene in a population.
Examples of descent with modification include the changes in the gene pool of a population over time. For example, in a population exposed to pesticides, the frequency of pesticide-resistant alleles might increase due to natural selection favoring those who possess them. This change over generations is an illustration of how organisms evolve and how allele frequencies shift in a population, indicating that descent with modification is taking place.