1. Describe the physiological origin of: gamete, sperm, egg, zygote
2. Why do females have sperm storage organs? What is the potential importance for male reproductive success in insectsof the following morphological fact: when present, the female's sperm storage organ is a sac with one opening.
3. Sexual selection is often evoked to explain characteristics that are expressed by males (less often by females) that appear to compromise survival. How could mate selection drive the evolution of characteristics that reduce survival?
4. Male reproductive strategy is sometimes in conflict with female reproductive strategy: what maximizes reproductive output for one sex does not necessarily do so for the other. What difference between male and female reproductive physiology is often evoked to explain this difference in strategy?
5. Under which of the following scenarios could new mating signals evolve through sexual selection? For each, explain why or why not evolution by sexual selection will not occur. Note: evolution by sexual selection requires the same three components as evolution by natural selection.
(A) Females in a population of moths vary in the ratio of different chemicals found in their pheromone signal. Daughters produce the same mixture of chemicals as their mothers regardless of the environmental conditions. Most males in the population prefer one particular chemical ratio of pheromones; females producing different combinations are less likely to mate. Sons tend to prefer the chemical ratio most similar to that of their mother.
(B) Males crickets respond to temperature: at warmer temperatures, the trill production is more frequent. Females must be at the same temperature in order to recognize the song of the males of their species.
(C) Male scarab beetles compete physically for matings with receptive females, and larger males with larger horns win most competitions. Male beetle size is determined primarily by how much the male gets to eat as a larvae, which is determined by the oviposition site of their mother (where she chooses to lay the egg). In turn, female oviposition behavior (choosing a host) is primarily determined by her ability to taste food: the chemoreceptors in her mouthparts. Daughters tend to oviposit upon the same food as their mothers.
6-8. Male crickets may engage in different strategies: calling to attract mates, which can involve singing competitions with other males (including physical confrontation) and may attract bats and parasitic flies; and waiting around without calling. These latter are referred to as "satellite males": they do not call, but try to court and copulate with females attracted to the singing males.
6. Classify each of the following as "sender", "receiver" or "both"
A. calling males
B. satellite males
C. receptive females
7. Would you expect satellite males to be larger, smaller, or the same size as calling males. Why?
8. Would you expect the "decision" to call or be a satellite to be dependent upon the level of competition (number of males singing)? Why or why not?
9. Why do low-doses of estrogen and progesteron inhibit ovulation?
10. What about the human female menstrual cycle makes the so-called "rhythm" method of contraception highly prone to errors?
11. What hormone is being detected in over-the counter and laboratory ovulation urine tests?
12. The presence what hormone(s) do over-the-counter and laboratory pregnancy tests check for?
13 The early birth control pill was a pure estrogen pill. The estrogen pill prevented pregnancy because
(A) ovulation is inhibited by the corpus luteum, which is stimulated by
estrogen.
(B) ovulation is stimulated by estrogen in high doses, and inhibited by
estrogen in low, constant doses.
(C) ovulation is inhibited because low dosages of estrogen inhibit the formation
of the uterine lining
(D) ovulation is stimulated by a peak of leutinizing hormone, LH, and LH
production is inhibited by low concentrations of estrogen.
(E) ovulation is stimuated by the gonadotropin releasing hormone (GnRH)
and GnRH production is inhibited by constant doses of estrogen.
14. When a female mammal becomes pregnant, the uterus lining is not lost and the ovaries cease developing more eggs. This is because
(A) the corpus luteum is maintained by leutinizing hormone produced by
the blastocyst (fertilized egg).
(B) the blastocyst (fertilized egg) produces gonadotropin releasing hormone,
preventing loss of the uterine lining.
(C) the corpus luteum and the blastocyst (fertilized egg) produce progesteron
and estrogen, preventing the loss of the uterine lining.
(C) the constant titers of progesteron and estrogen produced by the
corpus luteum and the blastocyst (fertilized egg) prevent the secretion of
follicle stimulating hormone.
15. It is very common for women undergoing hormone treatment for infertility to have multiple fetus pregnancies, caused by multiple ovulation. What hormone(s) are being used by the doctors?
(A) gonadotropin releasing hormone.
(B) human chorionic gonadotropin
(C) follicle stimulating hormone
(D) leutinizing hormone
(E) progesteron
(F) testosteron
(G) estrogen
See also: Content review #1, 2, 6; Concept review #1, 3, 4; Applying ideas #1, 2 (why are data concerning body size important?), 3, 6.