Final answer:
Natural selection is a fundamental process of evolution that acts on genetic variation within a population, favoring individuals who are better adapted, leading to evolutionary changes over time.
Step-by-step explanation:
The question relates to mechanisms of evolution, and among the options provided, selective breeding, horizontal gene transfer, epigenetics, and anthropogenesis are indeed mechanisms that can influence evolution. However, natural selection is not only a mechanism of evolution but a central and integral concept within evolutionary theory.
According to Darwinian theory, natural selection acts on the genetic variation within a population by favoring individuals that are better adapted to their environment. These individuals are more likely to survive and reproduce, passing their advantageous traits to the next generation. This process leads to populations evolving over time.
Therefore, it is clear that natural selection is not the correct answer when asked which one is not a mechanism of evolution. It is a fundamental process that shapes the evolution of species through differential survival and reproduction.