1. Slide 1 Gametogenesis makes sex cells by meiosis Lecture 13 – Gametogenesis and Fertilization

2. Slide 2 Gametogenesis – gamete formation by meiosis. Spermatogenesis – Sperm formation (1N) Oogenesis – Egg formation (1N)

3. Slide 3 Primary spermatocyte Secondary spermatocytes, 2N Spermatids, 1N Sperm, 1N 2N 1N Meiosis morphogenesis Spermatogenesis

4. Slide 4 Spermatogenesis occurs in testes

5. Slide 5 Cross section through testes’ tubes

6. Slide 6 sperm

7. Slide 7 Primary Spermatocyte Secondary Spermatocyte Spermatid Sperm flagella 2N 1N

8. Slide 8 Sperm morphogenesis (change of shape) nucleus mitochondrion Golgi complex

9. Slide 9 tail Acrosome with digestive enzymes nucleus Middle piece with mitochondria Head

10. Slide 10 Mitochondria

11. Slide 11 Primary Oocyte Secondary oocyte 2N 1N Meiosis morphogenesis Polar Body Ootid Polar body Polar bodies 1N OvumDie Oogensis

12. Slide 12 http://www.ucalgary.ca/UofC/eduweb/virtualembryo/PageMill_Images/image145.gif Secondary oocyte, 1N Polar body, 1N

13. Slide 13 Ovary releases Secondary Oocyte and Follicle Cells

14. Slide 14 Release of secondary oocyte (1N) surrounded by follicle cells (2N)

15. Slide 15 Secondary oocyte = 1N Follicle Cells = 2N nurse cells

16. Slide 16 http://www.nature.com/ncb/journal/v3/n2/images/ncb0201_e59_F1.gif Egg (oocyte) cytoplasm Plasma membrane Sperm use acrosome enzymes to penetrate zona pellucida

17. Slide 17 http://www.3ddoor.com/gallery/fertilization.jpg Fertilization = sperm + egg Egg (oocyte) surrounded by follicle cells

18. Slide 18 FERTILIZATION Two independent acts ~Egg Activation ~Amphimixis (union of nuclei)

19. Slide 19 http://www.luc.edu/depts/biology/dev/spersem.jpg Egg Activation = when sperm contacts egg membrane

20. Slide 20 http://sun.science.wayne.edu/~jram/zmfert.gif Sperm on surface of the egg about to enter the egg

21. Slide 21

22. Slide 22 http://www.southeasternfertility.com/graphics/vtours_goodferteggs.jpg Amphimixis = when sperm and egg nuclei unit

23. Slide 23 Aphids (small insects that suck nutrients from plants). Females reproduce female offspring by parthenogenesis until winter approaches then they have sexual reproduction. Parthenogenesis = egg activation w/o amphimixis