The primary purpose of sensory receptors in organisms is to detect environmental stimuli and convert them into nerve impulses, facilitating perception and response. These specialized cells are adapted to sense various stimuli, including light, sound, temperature, and chemical signals. Sensory receptors enable organisms to perceive their surroundings, which is crucial for survival, communication, and interaction with the environment. They play key roles in behaviors such as foraging, predation, and mate recognition, thereby influencing an organism's ability to thrive and adapt.