Essential Idea:
Sexual reproduction involves the
development and fusion of haploid gametes
Understandings:
- Spermatogenesis and oogenesis both involve mitosis, cell growth, two divisions of meiosis and differentiation
- Processes in spermatogenesis and oogenesis result in different numbers of gametes with different amounts of cytoplasm
- Fertilization in animals can be internal or external
- Fertilization involves mechanisms that prevent polyspermy
- Implantation of the blastocyst in the endometrium is essential for the continuation of pregnancy
- hCG stimulates the ovary to secrete progesterone during early pregnancy
- The placenta facilitates the exchange of materials between the mother and fetus
- Estrogen and progesterone are secreted by the placenta once it has formed
- Birth is mediated by positive feedback involving estrogen and oxytocin
Applications:
- The average 38-week pregnancy in humans can be positioned on a graph showing the correlation between animal size and the development of the young at birth for other mammals
Skills:
- Annotation of diagrams of seminiferous tubule and ovary to show the stages of gametogenesis
- Annotation of diagrams of mature sperm and egg to indicate functions