Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

In which type of organism is blood temperature typically constant, regardless of environmental conditions?

1. Reptiles

2. Amphibians

3. Mammals

4. Fish

The correct answer is: Mammals

In mammals, blood temperature is typically constant and maintained within a narrow range regardless of the environmental conditions. This characteristic is known as endothermy or warm-bloodedness. Mammals have physiological mechanisms, including metabolic processes, insulation (such as fur or fat), and behavioral adaptations that allow them to regulate their body temperature effectively. This enables them to thrive in various environments, from arctic regions to tropical climates. In contrast, reptiles, amphibians, and fish are ectothermic organisms, meaning their body temperature depends largely on the temperature of their surroundings. Reptiles may bask in the sun to raise their body temperature, amphibians may seek moisture or shade, and fish are influenced by the water temperature in which they live. As a result, these groups do not maintain a constant internal temperature and can experience fluctuations based on environmental conditions.