Organisms classified as ectothermic rely on external sources of heat to regulate their body temperature. Unlike endothermic organisms, which generate heat internally, ectothermic species—such as reptiles and amphibians—adapt to environmental temperatures. This characteristic allows them to conserve energy, as their metabolic rate decreases in cooler surroundings. However, it also makes them vulnerable to temperature fluctuations, affecting their behavior, reproduction, and survival in various habitats.