Phenotypic variation refers to the observable differences in physical and behavioral traits among individuals of the same species. These traits can include characteristics such as height, color, and shape, which arise from the interaction of an organism's genotype and its environment. This variation is essential for evolution, as it provides the raw material for natural selection. When individuals with advantageous traits reproduce, they pass these traits to the next generation, leading to changes in the population over time. Understanding phenotypic variation helps scientists study biodiversity and the adaptability of species.