Genotypes and Phenotypes

    Natural selection operates on phenotypes which are the observable traits of organisms. Because these traits determine how well individuals interact with their environment, they ultimately affect their survival and reproductive success. While it’s true that genotypes, the genetic blueprints, are what get passed to the next generation, the relationship between genotype and phenotype is important. Genotypes provide the potential for traits to exist, but environmental factors and developmental processes shape how these traits manifest. For example, in a population of rabbits, variations in speed can be linked to genetic differences, but it’s the faster individuals that are more likely to escape predators and reproduce. This differential survival leads to a higher frequency of advantageous alleles in the population over generations. As phenotypes that enhance survival and reproduction become more common, the underlying genotypes associated with those traits also increase in frequency. This process illustrates that while selection acts on phenotypes, it ultimately drives changes in the genotype of the population, leading to evolutionary change. A classic example is the peppered moth, where darker variants became more prevalent due to changes in environmental conditions. This illustrates how selection acting on observable traits can result in significant shifts in genetic makeup over time, demonstrating the dynamic between phenotype, genotype, and evolution.