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

What characterizes cold-blooded organisms in relation to their body temperature?

1. Their body temperature is constant

2. Their body temperature varies with the environment

3. They require higher levels of oxygen

4. They can generate heat through metabolism

The correct answer is: Their body temperature varies with the environment

Cold-blooded organisms, also known as ectothermic animals, are characterized by their inability to internally regulate their body temperature. Instead, their body temperature fluctuates with the surrounding environmental temperatures. This means that when the environment is warm, their body temperature increases, and conversely, when the environment is cold, their body temperature decreases. This trait leads to various behavioral adaptations, such as seeking sunlight to warm up or finding shade or water to cool down. Cold-blooded organisms rely heavily on environmental heat sources to thermoregulate, influencing their activity levels, metabolism, and overall biological processes. Thus, the variability in their body temperature according to environmental conditions fundamentally defines what cold-blooded organisms are and how they interact with their ecosystems.