Chapter 17

Breeding like rabbits" is a common expression for having large numbers of offspring. Rabbits are indeed noted for their great reproductive potential. Rabbits exhibit induced ovulation and postpartum estrus. Define these reproductive traits, and explain how they help endow rabbits with their considerable reproductive potential.

Suppose you are in charge of a captive breeding program for a species of zoo animal that is similar to humans in its reproductive endocrinology. By study of hormone signals, how could you tell when a female ovulates? If you permit her to mate at that time, how could you later tell from study of homone signals whether she has conceived? Explain your answers.

Estimate the age of a primary oocyte within a dominant follicle in the ovary of a woman on her 18 th birthday. Explain your reasoningr

Explain the advantages that both insects and mammals can realize from embryonic diapause.

Ovulation in mammals occurs in response to a surge of luteinizing hormone (LH). whether it is incluced or spontanecus. Compare and contrast the ways the LH surge is generated in induced and spontanecus onulators.

In discussions of feedback in biological systems, negative feedback is typically emphasized, and positive feedback is often treated as an anomaly. In fact, positive feedback is common in reproductive physiology. List two or three examples of positive feedback. Explain how positive feedback functions to advantage in each case. If possible, discuss whether homeostasis is always ideal.

In discussions of feedback in biclogical systems, negative feedback is typically emphasized, and positive feedback is often treated as an anomaly. In fact, positive feedback is common in reproductive physiology. List two of three examples of pooitive feedback. Explain how positive feedback functions to advantage in each case. If possible, discuss whether homeostasis is always ideal.

Consider a species, such as a lizard, in which females produce sets of eggs with large, heavy quantities of yolk. Suppose you hypothesize that one of the costs of reproduction is that females cannot run as fast or escape predators as well when they are in the process of producing such eggs. Describe a manipulative experiment you could carry out to test your hy pothesis, and explain how you would interpret your results. (For an example, see the paper by Miles et al. in the References.)

What are the relative advantages and disadvantages of semelparity and iteroparity? In answering consider iteroparcus species that have both short and long expected life spans in their natural ervironments.

Knowing what you do about the feedback effects of testosterone on the anterior pituitary gland, explain the reason that male athletes who take anabolic steroids become temporarily sterile (anabolic steroids are steroids that mimic some actions of testoeterone).

Aromatase inhibitors are a new generation of drugs used to treat women who have estrogen-sensitive breast cancers (cancers that grow most rapidly when estrogen is present). Explain why aromatase inhibitors are useful in these cases.

Prolactin and oxytocin are both involved in lactation. Define, describe, and explain the functional significance of each of these hormones.

Prolactin and oxytocin are both irrvolved in lactation. Define, describe, and explain the functional signifieance of each of these hormones.