Critical Thinking Questions
31. Why is sexual reproduction useful if only half the animals can produce offspring and two separate cells must be combined to form a third?
32. What determines which sex will result in offspring of birds and mammals?
33. What are the advantages and disadvantages of external and internal forms of fertilization?
34. Why would paired external fertilization be preferable to group spawning?
35. Describe the phases of the human sexual response.
36. Compare spermatogenesis and oogenesis as to timing of the processes and the number and type of cells finally produced.
37. If male reproductive pathways are not cyclical, how are they controlled?
38. Describe the events in the ovarian cycle leading up to ovulation.
39. Describe the major developments during each trimester of human gestation.
40. Describe the stages of labor.
41. What do you think would happen if multiple sperm fused with one egg?
42. Why do mammalian eggs have a small concentration of yolk, while bird and reptile eggs have a large concentration of yolk?
43. Explain how the different germ layers give rise to different tissue types.
44. Explain the role of axis formation in development.