Question

A desert lizard (an ectotherm) and a mouse(an endotherm) are placed inside a chamber at ${15}^o$C and their body temperature [T(L) for the lizard and T(M) for the mouse] and metabolic rates[M(L) for the lizard and M(M) for the mouse] are monitored. Which one of the following is correct?

• A. T(L) and M(L) will fall while T(M) M(M) will increase
• B. T(L) and M(L) will increase while T(M) and M(M) will fall
• C. T(L) and M(L) will fall, T(M) will remain same and M(M) will increase
• D. T(L) and M(L) will remain same and T(M) and M(M) will decrease

Answer 1

Answer: (C)

T(L) and M(L) will fall, T(M) will remain same and M(M) will increase

The desert lizard is an ectotherm hence its body temperature changes as per the environment. Hence its body temperature and metabolic rate will fall in order to adjust to the environment.

Whereas the mouse is an endotherm so its body temperature is constant due to metabolic rate variation. The metabolic rate is inversely proportional to environmental temperature.

Hence its body temperature will remain same and metabolic rate will rise.

Thus the correct answer is option C.