Perception is a universal phenomenon. It functions primarily as a means of allowing an organism to process changes in its external environment. Thus, perception has substantial survival value and can be observed in all living species. Its prevalence leads to questions about its origins and about how perceptual mechanisms have evolved. These questions require a firm understanding of evolution, particularly the main processes of innovation and constraint, and their interrelationship.

Evolution is considered as change in the inherited traits (particular characteristics) of a population of organisms from one generation to the next. These changes are caused by a combination of three main processes: variation (differences between genotypes underlying the traits, caused by, for example, mutation), reproduction (heritable traits are propagated between generations), and selection (individuals with ...