What is the primary mechanism of Darwin's theory of evolution?

The primary mechanism of Darwin's theory of evolution is natural selection and variation. Darwin proposed that individuals within a species exhibit variations in their traits, and those traits can affect their survival and reproductive success in their environment. For example, individuals with traits that provide an advantage in a particular environment are more likely to survive and reproduce, passing those advantageous traits to the next generation.

Natural selection acts on existing variations within a population, leading to changes in the population over time as favorable traits become more common and unfavorable traits decrease. This concept underscores the idea that evolution is not random, but rather, it is a process driven by environmental pressures that favor certain adaptations.

While mutation and genetic drift do contribute to the overall process of evolution, they are not the central mechanism described by Darwin. Mutation introduces new genetic variations, and genetic drift can affect allele frequencies in small populations, but these processes do not encompass the full picture of how adaptation occurs in response to environmental challenges, which is at the core of Darwin's theory. Additionally, artificial selection, while significant in the context of selective breeding, is distinct from the natural processes described by Darwin, and developmental biology and embryology, although informative about organismal development, do not address the mechanisms of evolutionary change as outlined in natural selection