Sexual Reproduction
Understandings:
• A gene on the Y chromosome causes embryonic gonads to develop as testes and secrete testosterone.
• Testosterone causes pre-natal development of male genitalia and both sperm production and development of male secondary sexual characteristics during puberty.
• Estrogen and progesterone cause pre-natal development of female reproductive organs and female secondary sexual characteristics during puberty.
• A gene on the Y chromosome causes embryonic gonads to develop as testes and secrete testosterone.
• Testosterone causes pre-natal development of male genitalia and both sperm production and development of male secondary sexual characteristics during puberty.
• Estrogen and progesterone cause pre-natal development of female reproductive organs and female secondary sexual characteristics during puberty.
The menstrual cycle is controlled by negative and positive feedback mechanisms involving ovarian and pituitary hormones
The roles of FSH, LH, estrogen and progesterone in the menstrual cycle are expected.
Hormones are used in a variety of therapies such as replacement therapies.
The roles of FSH, LH, estrogen and progesterone in the menstrual cycle are expected.
Hormones are used in a variety of therapies such as replacement therapies.
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• Skill: Annotate diagrams of the male and female reproductive system to show names of structures and their functions.
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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: Spermatogenesis results in 4 sperm cells from one germ cell (spermatogonium). Oogensis results in 3 polar bodies and 1 ovum (received majority of the cytoplasm) from the germ cell (oogonium). |
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Skill: Annotation of diagrams of seminiferous tubule to show the stages of gametogenesis.
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Skill: Annotation of diagrams of the ovary to show the stages of gametogenesis.
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Skill: Annotation of diagrams of mature egg and sperm to indicate functions.
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Fertilization involves mechanisms that prevent polyspermy.
Fertilization involves the acrosome reaction, fusion of the plasma membrane of the egg and sperm and the cortical reaction. |
Development of the embryo:
• 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.
Cleavage --> Gastrulation --> Neurulation --> Organogenesis
• 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.
Cleavage --> Gastrulation --> Neurulation --> Organogenesis
Blastocyst
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Cleavage - first stage of embryological development
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Aim 8: Scientists are aware that the drugs women take in fertility treatment pose potential risks to health.
ToK: Should scientific knowledge override compassionate considerations in treating infertile couples?
ToK: Should scientific knowledge override compassionate considerations in treating infertile couples?
Application: The use in IVF of drugs to suspend the normal secretion of hormones, followed by the use of artificial doses of hormones to induce superovulation and establish a pregnancy.
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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.
correlation between animal size and the development of the young at birth for other mammals.
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