Which process involves the alteration of species populations due to environmental changes?

Natural selection is the process that involves the alteration of species populations due to environmental changes. It is the mechanism by which organisms that are better adapted to their environment tend to survive and reproduce, leading to the gradual evolution of species. This process is influenced by factors such as competition for resources, predators, diseases, and varying environmental conditions that affect survival and reproduction rates.

For instance, if a particular species encounters a change in its habitat, such as a shift in climate or the introduction of a new predator, individuals with traits that favor survival in that new environment are more likely to reproduce. Over time, those advantageous traits become more common within the population, leading to changes in the species over generations.

While the other options involve changes within populations and species, they do not specifically encompass the concept of environmental influence on population alteration in the same direct manner as natural selection does. Genetic drift refers to random changes in allele frequencies that can lead to population divergence, population dynamics studies changes in population sizes and structures, and speciation involves the formation of new species rather than the alteration of existing populations due to environmental changes.