Final answer:
Skin color shows genetic variation in humans and is a polygenic trait controlled by multiple genes. An example of phenotypic plasticity for skin color is tanning, which is a reversible change in response to sunlight exposure. There is genotype-by-environment interaction for skin color, where both genetic and environmental factors influence the amount of melanin produced in the skin. Phenotypic plasticity for skin color can evolve in human populations through natural selection.
Step-by-step explanation:
Yes, skin color does show genetic variation in humans. It is a polygenic trait, meaning that it is controlled by multiple genes. The variation in skin color is due to different amounts of melanin production in the skin.
An example of phenotypic plasticity for skin color is tanning. When exposed to sunlight, the skin produces more melanin to protect against harmful UV radiation, causing the skin to darken. This is a reversible change that occurs in response to environmental stimuli.
There is also genotype-by-environment interaction for skin color. The amount of melanin produced in the skin is influenced by both genetic factors and environmental factors, such as sun exposure. Different individuals with the same genetic makeup may have different skin colors depending on their environmental conditions.
Yes, phenotypic plasticity for skin color can evolve in human populations. Natural selection can favor individuals with the ability to adjust their skin color in response to environmental conditions. Over time, populations with higher levels of phenotypic plasticity for skin color may have a higher chance of survival and reproduction, leading to evolutionary change.