Continuous Variation: individuals in a population vary within a range, eg. Height.
Discontinuous Variation: only two or more categories, no intermediates, eg. Blood type, Gender.
Genes and Environment.
Differences in genotype result in variation in phenotype.
Inherited characteristics that are continuous variation are influenced by many genes, they are polygenic.
Discontinuous inherited are influenced by one gene, they are monogenic.
Climate, food, and lifestyle are all environmental effects.
Environmental factors can influence how characteristics develop, most variation is caused by a combination of the two.
Individuals which are better adapted to selection pressures are more likely to reproduce and pass on beneficial alleles.
Environment can affect which characteristics become common.
When the environment doesn't change, middle range characteristics are more likely to survive. This…