Although estrogen is primarily produced by ovaries,it is also produced by the adrenal glands and in fat tissue.Loss of the normal amount of fat lowers the level of estrogen so that the menstrual cycle and ovulation stops.Female Olympic athletes who train severely often shut off their cycles.What would be a reasonable evolutionary cause of this shutdown?
A)This mechanism shifts use of energy from reproduction to life activities for staying alive.
B)Since an unborn infant gets priority on blood nutrient pools,pregnancy during famine will likely be fatal for both mother and offspring; this mechanism reduces this risk and increases survival.
C)The adrenal glands have evolved to produce fight-or-flight responses and natural selection has shifted them to this function and away from estrogen.
D)Less food would result in less hormone production.
E)Evolution always selects for simpler systems.

Question

Quizplus · Accepted Answer

Evolution has most likely selected for this mechanism in order to reduce the risk of pregnancy during famine, which would likely result in higher mortality rates for both mother and offspring. By shutting down the menstrual cycle and ovulation, the body is able to conserve resources for survival rather than reproduction. This is a protective mechanism that has been selected for through natural selection.

Although Estrogen Is Primarily Produced by Ovaries,it Is Also Produced