Final answer:
The range of forms of any human characteristic, such as body shape or skin color, is called human biological variation. This concept refers to the variations in physical traits that exist within the human population. Each human trait varies along a spectrum, and there are no discrete categories based on race.
Step-by-step explanation:
The range of forms of any human characteristic, such as body shape or skin color, is called human biological variation. This concept refers to the variations in physical traits that exist within the human population. Human traits, including skin color, facial features, hair texture, and blood type, vary along a spectrum, and there are no discrete categories based on race. Each human trait varies among people in ways that make racial distinctions inaccurate.
Biological anthropology and genetic research have shown that race is not a scientifically valid concept. Skin color, for example, varies along a spectrum from pinkish beige to dark brown, and every possible shade exists between those two extremes. The traditional theory of directional selection suggests that human phenotypes, including skin pigmentation, have evolved to adapt to different levels of exposure to ultraviolet rays from the sun.
Cultural factors and regional standards of beauty have also played a role in the evolution of physical appearance. Long-standing standards of attractiveness have influenced regional evolutionary changes in body morphology, such as height and body shape. It's important to note that there is more genetic variation within a given racial category than between racial categories.