The term gene pool refers to the sum total of all the genetic information stored within any given population. A gene is a specific portion of a DNA (deoxyribose nucleic acid) molecule, so a gene pool is the sum total of all of the DNA contained within a population of individuals.

The concept of gene pool is important in ecological studies because it reveals changes that may or may not be taking place within a population. In a population living in an ideal environment for its needs, the gene pool is likely to undergo little or no change. If individuals are able to obtain all the food, water, energy, and other resources they need, they experience relatively little stress and there is no pressure to select one or another characteristic.

Changes do occur in gene frequency because of natural factors in the environment. For example, natural...