4. Genetic Variation

Every person is born with genetic differences, called variation. Variation is why each individual is unique at the level of genes and traits. Most variation is harmless, but some causes disease. Genetic and trait variation allows populations to adapt more readily to different environmental challenges. In fact, variation in populations is necessary for the evolution of species. Because many traits and conditions are the result of combinations of genes and environment, we see a wide range of variation for most traits in the population.

Genetic Variation