Final answer:
Cold-blooded animals, or ectotherms, depend on external temperatures to regulate their body heat, while warm-blooded animals, or endotherms, maintain a constant body temperature through internal metabolic processes. Fish, including those in class Pisces, are cold-blooded. Endotherms have various adaptations like fur, feathers, and fat for heat conservation and ways to adjust their circulatory system for temperature regulation.
Step-by-step explanation:
Cold-blooded and warm-blooded animals differ mainly in how they regulate body temperature. Cold-blooded animals, also known as ectotherms, have body temperatures that vary with their environment. They rely on external heat sources to regulate their body temperature. Examples include reptiles and fish. In contrast, warm-blooded animals, or endotherms, can regulate their body temperature internally through metabolic processes, allowing them to maintain a constant body temperature despite environmental changes. This group includes mammals and birds.
Regarding the class Pisces, they are placed in the category of cold-blooded animals because, as fish, their internal body temperature adjusts according to the surrounding water temperature. This characteristic is a defining trait of ectotherms. Members of Pisces have other distinguishing features, such as scales, paired and unpaired fins, and streamlined bodies for efficient swimming.
The ability for endotherms to maintain internal heat allows cellular processes to operate efficiently even in cooler environments, which is not possible for ectotherms with varying enzyme levels of activity. Endotherms like mammals and birds also possess adaptations like fur, feathers, and fat to conserve heat, and use circulatory system adjustments such as vasodilation and vasoconstriction to regulate body temperature.