Reproduction and Development

1. Reproduction and Development Aim: To elaborate on the different types of reproduction Do Now: Explain the differences between asexual and sexual reproduction

2. Species:a group of closely related organisms that share certain characteristics and can mate and produce viable offspring

4. Asexual Reproduction • Asexual Reproduction can happen in different ways • Budding: an outgrowth later comes off and becomes a new individual • Binary Fission: The parent divides into two daughter cells

5. Asexual Reproduction • Bacteria, algae, most protozoa, yeast, dandelions, and flatworms all reproduce asexually. • Offspring are clones of parents

6. Sexual Reproduction • Sex cells: (gametes) egg or sperm cells • Fertilization: process where egg and sperm cells are joined together • Sperm: sex cell from the father • Egg: sex cell from the mother • Offspring will be similar to their parents, BUT NOT identical

7. Cloning • Cloning:a way of making identical genetic copies – 100% of the DNA comes from one parent

8. Cell Division • Mitosis: cell’s genetic material divides creating two complete sets of the cell’s genetic material • IPMATC

9. Mitosis All the cells DNA is found in the cell nucleus in structures called chromosomes

10. Mitosis When cells divide, the chromosomes appear, divide and separate

11. Mitosis Two new cells form with identical chromosomes to the original cell

12. Here are the main cell parts involved in mitosis- Centrioles Cell Membrane Nucleolus Chromatin network Nuclear Envelope

13. MITOSIS can be divided into FIVE different stages: • Interphase • Prophase • Metaphase • Anaphase • Telophase

14. Remember the sequence IPMAT • Interphase • Prophase • Metaphase • Anaphase • Telophase • I • P • M • A • T

15. Interphaseoccurs before mitosis begins Chromosomes are copied (# doubles) Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy (sister chromosome) change to sister chromatids at end of this phase CELL MEMBRANE Nucleus Cytoplasm

16. Interphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

17. Prophase 1st step in Mitosis Mitosis begins (cell begins to divide) Centrioles(or poles) appear and begin to move to opposite ends of the cell. Spindle fibers form between the poles. Centrioles Sister chromatids Spindle fibers

18. Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

19. Metaphase 2nd step in Mitosis Chromatids (or pairs of chromosomes) attach to the spindle fibers. Centrioles Spindle fibers

20. 7 MITOSIS – Metaphase - Chromosomes line up SINGLE FILEat the Equator

21. Metaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

22. Anaphase 3rdstep in Mitosis Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers

23. 8 MITOSIS – Anaphase- Double stranded Chromosomes split to form TWO single stranded chromosomes

24. 9 MITOSIS – Anaphase Single stranded chromosomes move to opposite poles

25. Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

26. Aim: What are the stages of mitosis? Do Now: If you had fallen this morning on the way to school, how would your body repair itself? What process would it use?

27. Telophase4th step in Mitosis Two new nuclei form. Chromosomes appear as chromatin (threads rather than rods. Mitosis ends. Nuclei Nuclei Chromatin

28. Telophase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

29. MITOSISOriginal Cell Divides to form TWO new cells with the SAME number of chromosomes

30. Cytokinesisoccurs after mitosis Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

31. http://www.icompositions.com/music/song.php?sid=110420 http://www.nclark.net/MitosisMeiosis

32. Animal Mitosis -- Review

33. Plant Mitosis -- Review

34. Meiosis

35. Meiosis • Cell division to form the gametes, sperm (male gamete) and egg (female gamete). • Normal cells are diploid: 2 copies of every gene. • Gametes are haploid: 1 copy of every gene • Need to choose 1 copy of each gene randomly.

36. Somatic (body) cells have 46 chromosomes - Diploid • Sex (egg and sperm) cells have 23 chromosomes - Haploid

37. Why have sexual reproduction? • Shuffling of alleles between parents and offspring leads to new combinations. • Bad combinations die without reproducing; good combinations survive and reproduce more offspring.

38. Aim: What are the differences between mitosis and meiosis? • Do Now: List and explain the steps of mitosis

39. http://www.classroom20.com/video/649749:Video:104840

40. Overview • Start with a diploid cell, with 2 copies of each chromosome, one form each parent. • Use 2 cell divisions: • Meiosis 1. First separate the homologues • Meiosis 2. Then separate the 2 chromatids. • The stages of meiosis have the same names as in mitosis

41. Meiosis 1 • Two important events in meiosis 1: • crossing over in prophase • pairing of homologues in metaphase. • Crossing over. Homologues break at identical locations, then rejoin opposite partners. Results in mixing of the genes you inherited from your parents.

42. More Meiosis 1 • At metaphase, the pairs of homologous chromosomes line up side by side. This does not happen in mitosis of meiosis 2. • At anaphase of meiosis 1, the pairs of homologues are pulled to opposite poles by the spindle.

43. Result of Meiosis 1 • Go from 1 cell to 2 cells. Each daughter cell contains 1 copy of each chromosome • For humans: start with one cell containing 46 chromosomes (23 pairs) to 2 cells containing 23 chromosomes. • As a result of crossing over, each chromosome is the mixture of the original homologues.

44. Meiosis 2 • Meiosis 2 is just like mitosis • No replication of DNA between meiosis 1 and meiosis 2. • Chromosomes line up individually on the equator of the spindle at metaphase. • At anaphase the centromeres divide, splitting the 2 chromatids. • The one-chromatid chromosomes are pulled to opposite poles.

45. More Meiosis 2

46. Summary of Meiosis • 2 cell divisions. • Start with 2 copies of each chromosome (homologues), each with 2 chromatids. • In meiosis 1, crossing over in prophase mixes alleles between the homologues. • In metaphase of meiosis 1, homologues pair up, and in anaphase the homologues are separated into 2 cells. • Meiosis 2 is just like mitosis. A total of 4 cells, each with 1 copy of each chromosome,

47. Life Cycles • Meiosis converts a diploid cell into haploid cells. Fertilization combines the 2 haploid gamete cells (sperm and egg) back into a diploid cell. • Eukaryotes alternate between diploid and haploid stages. This is called the life cycle of the organism.

48. Gamete Formation in Animals • Differences between male and female gametes. • In males, all 4 products of meiosis develop into sperm cells. • In females, the cell divisions of meiosis are uneven: most of the cytoplasm goes into 1 of the 4 meiotic products, which becomes the egg. The other 3 meiotic cells are small “polar bodies”, which degenerate.

50. During Prophase I of meiosis, chromosomes undergo crossing over: which is the exchange of genetic information