Final answer:
Fixed action patterns are innate behaviors that increase an individual's fitness by providing reliable, predictable responses to stimuli, as illustrated by the aggressive response of male stickleback fish to the red coloration signaling a rival.
Step-by-step explanation:
Fixed action patterns tend to increase fitness because they generate predictable responses to a stimulus, and because they are innate behaviors. An example is observed in the three-spined stickleback fish. During breeding season, males develop a red belly and exhibit aggressive behaviors towards the red coloration on other males, which is a predictor of a rival. Even when a non-fish object with red coloring is presented, the male sticklebacks respond with aggression, showing the predictability and innateness of this fixed action pattern. This behavior enhances reproductive success by deterring potential rivals, contributing to an individual's fitness.
From an evolutionary standpoint, fixed action patterns are beneficial because they help an organism respond quickly and effectively to specific environmental stimuli without the need for prior learning. These behaviors are therefore reliable, reduce the need for decision-making in critical situations, and often lead to increased survival and reproductive success. These patterns tend to enhance fitness because they generate predictable responses, which can be advantageous for survival and reproduction. For example, male stickleback fish show aggressive behaviors towards objects that resemble other male sticklebacks, even if they are not actual fish. This predictable response helps them defend their breeding territory and increases their chances of reproductive success.