Final answer:
Testosterone production is a temporal response that varies with age, with ultimate causes tied to evolutionary benefits. Large intakes of synthetic testosterone can lead to a decrease in natural testosterone production due to the body's negative feedback mechanisms.
Step-by-step explanation:
Testosterone production can be considered a temporal physiological response as it varies with age, being high during puberty and gradually declining in adulthood—a condition known as andropause. It is regulated by the endocrine system through a complex interplay with the reproductive system, ensuring normal male reproductive function. A possible ultimate cause for the increase in testosterone could be the evolutionary advantage it confers in terms of increased muscle mass, reproductive capabilities, and the development of secondary sexual characteristics which may be considered advantageous for sexual selection.
Regarding external testosterone intake, when an individual takes large amounts of synthetic testosterone, such as anabolic steroids, the body's negative feedback loop will trigger a decrease in natural testosterone production by the testes. The body recognizes the excess testosterone and reduces its own production to maintain homeostasis, which could potentially lead to reduced testicular size and compromised reproductive health.