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Human Development

Human Development. 27.9 Relate the structure of sperm to its role in fertilization. Describe the mechanisms that prevent more than one sperm from fertilizing an egg and that prevent hybridization between different species. Describe this picture….

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Human Development

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  1. Human Development

  2. 27.9Relate the structure of sperm to its role in fertilization. Describe the mechanisms that prevent more than one sperm from fertilizing an egg and that prevent hybridization between different species.

  3. Describe this picture…

  4. 27.10 Describe the process and results of cleavage. Explain how identical and nonidentical twins form.

  5. Describe this picture…

  6. 27.11 Describe the process of gastrulation and the resulting arrangement of the embryo.

  7. Gastrulation gastrulation inprimitive chordates ectoderm mesoderm endoderm • Establish 3 cell layers • ectoderm • outer body tissues • skin, nails, teeth • nerves, eyes, lining of mouth • mesoderm • middle tissues • blood & lymph, bone & notochord, muscle • excretory & reproductive systems • endoderm • inner lining • digestive system • lining of respiratory, excretory & reproductive systems protostome vs. deuterostome

  8. 27.12 Explain how organs form after the development of a gastrula.

  9. Explain how changes in cell shape, induction, cell migration, and apoptosis contribute to development

  10. Pattern formation during embryonic development is controlled by ancient genes

  11. 27.15 Describe the initial embryonic stages and the formation and functions of the extraembryonic membranes in humans.

  12. Human fetal development 5 weeks 4 weeks

  13. Human fetal development 10 weeks

  14. Human fetal development 14 weeks 20 weeks

  15. Human fetal development Week 20 • The fetus just spends much of the 2nd & 3rd trimesters just growing …and doing various flip-turns & kicks inside amniotic fluid

  16. Human fetal development fetus is covered with fine, downy hair called lanugo. Its skin is protected by a waxy material called vernix 24 weeks (6 months; 2nd trimester)

  17. Human fetal development umbilical cord 30 weeks (7.5 months)

  18. Getting crowded in there!! The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming 32 weeks (8 months)

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