LG: What happens after fertilization?

1. LG: What happens after fertilization?

2. Do Now (2/24)-5minutes 5 minutes • In your notebook, complete the chart below:

3. HW C1 Due • E/F 8. D • C 9. A • B 10. B • D 11. A • B 12. D • B 13. C • B 14. B

4. EMBRYO From one cell to many cells • A fertilized egg (Zygote) goes through an early stage of development called an embryo.

5. Sexual vs. Asexual Reprod.

6. Regents Practice-5minutes (In your group, discuss and complete the following) From C2 Worksheet: #1, 3, 5, 7 5 minutes

7. Asexual Reprod. Starfish: Regeneration Hydra: Budding

8. Parthenogenesis: When Animals Reproduce Without a Mate

9. Variation from random fertilization • Sperm + Egg = ? • any 2 parents will produce a zygote with over 70 trillion (223 x 223) possible diploid combinations

10. Michael & KirkDouglas Baldwin brothers Martin & Charlie Sheen, Emilio Estevez Sexual reproduction creates variations Sexual reproduction allows us to maintain both genetic similarity & differences.

11. Regents Question

12. Fertilization: Four Major Steps • Sperm contacts the egg • Sperm or its nucleus enters the egg • Egg becomes activated and developmentalchanges begin • Sperm and egg nuclei fuse

13. Fertilization: sperm unites with an egg in the fallopian tube23 chromosomes (sperm) + 23 chromosomes (egg) =46 chromosomes (zygote) http://www.doctoroz.com/videos/fertilization-animation

14. Fertilization

15. Internal or External? external internal external internal external

17. Implantation • The embryo implants in the wall of the uteruson about the 7th day of development

18. The Nuclei Fuse Together

19. What happens now? • Development of the zygote • The zygote undergoes a series of mitotic cell divisions called cleavage. • The stages of development are: Fertilized ovum (zygote)  2-cell stage  4-cell stage  8-cell stage  Morula  Blastula  Early Gastrula  Late Gastrula

20. Twins • Dizygotic or fraternal twinsoccur when two separate eggs are ovulated. May be of different sexes. • Monozygotic or identical twins occur when a single egg is fertilized but dividing cells break into two groups and develop into two individuals. Genetically identical (clones)

21. Cleavage (divide via mitosis) forms the 2 cell stage

22. They split again to form the 4 cell stage

23. And again to form the 8 cell stage…

24. And eventually form a Morula • Morula – solid ball of cells formed from cleavage

25. Next it becomes a blastula • Blastula – hollow ball of cells formed from cleavage

26. And next, a gastrula • Gastrula – a hollow ball of cells with an “in pushing” and 3 layers (germ layers)

27. Human Embryonic Development The Three Germ Layers: Ectoderm, Mesoderm and Endoderm

28. Week 8-9

29. The Regents Diagram… • Sperm (23 chromosomes) and ovum (23 chromosomes) = fertilization • Zygote (fertilized ovum) • 2-cell stage • 4-cell stage • Morula (solid) • Blastula (hallow) • Gastrula (hallow with 3 germ layers) Cleavage: process of cell division (Mitosis)

30. Regents Question

31. Regents Question

32. Differentiation (Organogenesis) • Organogenesis is the formation of the organs (Organo = organs, genesis = creation) • occurs during gastrula stage

33. Late Gastrula Endoderm Ectoderm Mesoderm

34. Differentiation of Germ Layers

35. Early Human Development Summary • Meiosis makes sperm in males and ovum in females • Sperm and ovum unite nuclei to form a zygote • Zygote undergoes cleavage and becomes gastrula with 3 germ layers (differentiation starts)

36. Implantation anywhere outside the uterus is called an ectopic pregnancy. • Growth inside the uterine tube causes the tube to rupture, resulting in severe bleeding.

37. Development of the Placenta

38. Placenta • Transports oxygen, nutrients, and antibodies to the fetus through the umbilical vein • Removes carbon dioxide and metabolic wastes from the fetus by the two umbilical arteries

39. http://www.youtube.com/watch?v=yENd7IElwP0

41. UMBILICAL CORD Connecting link between fetus and placenta. • Transports oxygen and nutrients to fetus from the placenta and returns waste products from the fetus to the placenta. • Contains: 2 arteries and 1 vein • Contains NO pain receptors. • Contains Stem Cells

42. Regents Question • Identify the structure in the uterus where the exchange of material between the mother and the developing fetus takes place. _____________________________________

43. 2/26 DO NOW-5 minutes (In your group, discuss and complete the following) From C2 Worksheet: #1

44. 10 minutes 2/26 DO NOW-10 minutes • Define fertilization and describe the resulting development of a human embryo. In your answer, be sure to include a definition of fertilization and the functions of the ovary, uterus, and placenta. Circle the terms fertilization, ovary, uterus, and placenta in your description.

45. Example of a 4-Credit Response Eggs are produced in the ovaries. Fertilization occurs when a sperm unites with an egg in the fallopian tube. An embryo forms and is implanted into the uterus. A placenta develops and helps provide nutrients for the embryo.

46. Regents Question

47. Regents Question

48. Do Now Regents Question 2/28

49. HW C3 Disease Project • Due 3/3 Monday

50. Do Now label each diagram 2/28 1: ___________________________ 2: ___________________________ 3: ___________________________ 4: ___________________________ 5: ___________________________ 6: ___________________________ 7: ___________________________