Photo AI
Why do some ectotherms bask in the sun? A - HSC - SSCE Biology - Question 1 - 2018 - Paper 1
Question 1
Why do some ectotherms bask in the sun? A. To absorb vitamin D B. To increase their activity C. To decrease their metabolic rate D. To constrict blood vessels close... show full transcript
Worked Solution & Example Answer:Why do some ectotherms bask in the sun? A - HSC - SSCE Biology - Question 1 - 2018 - Paper 1
Step 1
To absorb vitamin D
Answer
Ectotherms, or 'cold-blooded' animals, rely on external sources of heat to regulate their body temperature. By basking in the sun, they can increase their body temperature, which is essential for maintaining various physiological processes. While absorbing vitamin D is essential for many organisms, it primarily applies to vertebrates such as reptiles and amphibians, which utilize sunlight for this process. However, the main reason for basking is to increase their overall body activity level, which is vital for their survival.
Step 2
To increase their activity
Answer
Basking in the sun raises the ectotherm's body temperature, which in turn increases their activity levels. This heightened metabolic state allows them to hunt more efficiently, evade predators, and engage in reproductive activities. Ectotherms do not generate their own body heat; thus, their activity is significantly influenced by ambient temperatures.
Step 3
Step 4
To constrict blood vessels close to the skin
Answer
Basking in the sun is not primarily for the purpose of constricting blood vessels. Instead, ectotherms bask to absorb warmth and boost their activity. Blood vessel constriction would not be advantageous when trying to warm up, making this option incorrect.