Final answer:
After marine iguanas leave the cold ocean and start basking on warm rocks, their heart rate b. decreases to conserve energy. For humans, an increase in heart rate above 160 bpm results in a decrease in cardiac output.
Step-by-step explanation:
Marine Iguanas and Heart Rate
For marine iguanas, upon leaving the cold ocean to bask on warm rocks, the heart rate initially decreases. This response is a physiological adaptation to conserve energy after being in the cold water and to assist with thermoregulation. When mammalian heart rate increases significantly, such as above 160 bpm in a healthy young adult, cardiac output actually decreases rather than increases, which may run counter to what might be expected.
In both ectotherms like marine iguanas and endotherms like humans, the body has ways to manage heart rate and energy expenditure in response to environmental changes.After marine iguanas leave the cold ocean and start basking on warm rocks, their heart rate b. decreases to conserve energy. For humans, an increase in heart rate above 160 bpm results in a decrease in cardiac output.