Chapter 46, animal reproduction What are various modes of animal reproduction? What are the main anatomical features of male and female reproductive tracts in most animals? What are characteristic features of mammalian oogenesis (what are the cells produced during meiosis and when, where, and how many)? What are characteristic features of mammalian spermatogenesis (what are the cells produced during meiosis and when, where, and how many)? What is the role of hormones in human gametogenesis? What is the ovarian cycle? In humans, where does fertilization occur? What are the major events of early human embryogenesis and where in the body do they occur? How does the embryo stop the ovarian cycle? What is the function of the placenta? What initiates labor? Why are human babies so immature? Essay question What is the role of the brain (hypothalamus) in male and female gametogenesis?