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 and skills:
- Application: 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.
- Skill: Annotation of diagrams of seminiferous tubule and ovary to show the stages of gametogenesis.
- Skill: Annotation of diagrams of mature sperm and egg to indicate functions.
Guidance: Fertilization involves the acrosome reaction, fusion of the plasma membrane of the egg and sperm and the cortical reaction. |
Utilization:
- Syllabus and cross-curricular links:
- Biology
- Topic 3.3 Meiosis
- Topic 6.6 Hormones, homeostasis and reproduction
Aims:
- Aim 8: Disputes over the responsibility for frozen human embryos.
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