AP BIOLOGY

Detailed explanation-1: -Genetic Variation is Essential for Evolution by Natural Selection. For natural selection to occur, a population must have a wide variety of individuals with different traits. For example, natural selection would not influence fish body color if all individuals in a population were exactly the same color.

Detailed explanation-2: -Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.

Detailed explanation-3: -There are four principles at work in evolution-variation, inheritance, selection and time. These are considered the components of the evolutionary mechanism of natural selection.

Detailed explanation-4: -The essence of Darwin’s theory is that natural selection will occur if three conditions are met. These conditions, highlighted in bold above, are a struggle for existence, variation and inheritance. These are said to be the necessary and sufficient conditions for natural selection to occur.

Detailed explanation-5: -The three conditions that must be met in order for natural selection to occur and result in evolutionary change are traits, inherited, and selection pressure.