Final answer:
Rigid patterns of behavior inherent in a species are called innate behaviors or instinctive behaviors, such as the fixed action pattern observed in three-spined sticklebacks, which is an instinctual sequence carried out to completion in response to specific stimuli.
Step-by-step explanation:
Rigid patterns of behavior characteristic of a species and developed without practice are known as innate behaviors or instinctive behaviors. These behaviors are inherent in an organism and are exhibited by all members of a species in response to specific stimuli. An excellent example of such behavior is the fixed action pattern, which is a sequence of instinctual movements that, once initiated, will be carried out to completion regardless of subsequent changes in the environment. A classic example of a fixed action pattern can be observed in the three-spined stickleback during the breeding season, where males instinctually show aggressiveness towards other males or even inanimate objects with red undersides.
These behaviors are crucial for survival and reproduction, as they involve basic life functions such as foraging, mating, and caring for offspring. Since these behaviors do not require learning, they ensure that essential tasks are performed correctly from the outset, thereby giving individuals within the species a better chance of survival.