1. CAMPBELL BIOLOGY IN FOCUS © 2014 Pearson Education, Inc. Urry Cain Wasserman Minorsky Jackson Reece Lecture Presentations by Kathleen Fitzpatrick and Nicole Tunbridge 10 Meiosis and Sexual Life Cycles

2. © 2014 Pearson Education, Inc. Inheritance of Genes  __________________________________________

3. © 2014 Pearson Education, Inc. Sets of Chromosomes in Human Cells  __________________________________________ __________________________________________

4. © 2014 Pearson Education, Inc. Figure 10.3 ApplicationTechnique Pair of homologous duplicated chromosomes Centromere Sister chromatids Metaphase chromosome 5  m

5. © 2014 Pearson Education, Inc.  _________________________________________

6. © 2014 Pearson Education, Inc. Figure 10.4 Key Centromere Pair of homologous chromosomes (one from each set) Sister chromatids of one duplicated chromosome Two nonsister chromatids in a homologous pair 2n  6 Maternal set of chromosomes (n  3) Paternal set of chromosomes (n  3)

7. © 2014 Pearson Education, Inc. multicelled body meiosis diploid fertilization zygote gametes haploid Fig. 10-8b, p.162 Animal Life Cycle

8. © 2014 Pearson Education, Inc. Figure 10.6a Key Haploid (n) Diploid (2n) Gametes MEIOSIS FERTILIZATION Zygote n n n 2n2n2n2n Mitosis Diploid multicellular organism (a) Animals

9. © 2014 Pearson Education, Inc. Figure 10.6b MEIOSIS 2n2n 2n2n FERTILIZATION n n n n n Spores Gametes Mitosis Haploid multi- cellular organism (gametophyte) Zygote Mitosis (b) Plants and some algae Diploid multicellular organism (sporophyte) Key Haploid (n) Diploid (2n)

10. © 2014 Pearson Education, Inc. Figure 10.6c Key Haploid (n) Diploid (2n) FERTILIZATION n n n n n Mitosis Haploid unicellular or multicellular organism Gametes Zygote 2n2n MEIOSIS (c) Most fungi and some protists

11. © 2014 Pearson Education, Inc. Concept 10.3: Meiosis reduces the number of chromosome sets from diploid to haploid  ________________________________________ ________________________________________  ________________________________________ (that become gametes)

12. © 2014 Pearson Education, Inc. Figure 10.7 Interphase Duplicated pair of homologous chromosomes Pair of homologous chromosomes in diploid parent cell Chromosomes duplicate Diploid cell with duplicated chromosomes Sister chromatids Homologous chromosomes separate Sister chromatids separate Haploid cells with duplicated chromosomes Meiosis I Meiosis II Haploid cells with unduplicated chromosomes 1 2

13. © 2014 Pearson Education, Inc. Figure 10.7a Interphase Duplicated pair of homologous chromosomes Pair of homologous chromosomes in diploid parent cell Chromosomes duplicate Diploid cell with duplicated chromosomes Sister chromatids

14. © 2014 Pearson Education, Inc. Figure 10.7b Homologous chromosomes separate Sister chromatids separate Haploid cells with duplicated chromosomes Meiosis I Meiosis II Haploid cells with unduplicated chromosomes 1 2

15. © 2014 Pearson Education, Inc.  ________________________________________ Animation: Meiosis Video: Meiosis I in Sperm Formation

16. © 2014 Pearson Education, Inc. Figure 10.8a MEIOSIS I: Separates homologous chromosomes Prophase IMetaphase IAnaphase I Telophase I and Cytokinesis Sister chromatids Centromere (with kinetochore) Sister chromatids remain attached Centrosome (with centriole pair) Metaphase plate Chiasmata Spindle Cleavage furrow Homologous chromosomes separate Microtubule attached to kinetochore Fragments of nuclear envelope Homologous chromosomes

17. © 2014 Pearson Education, Inc. Figure 10.8b MEIOSIS II: Separates sister chromatids Prophase IIMetaphase IIAnaphase II Telophase II and Cytokinesis Sister chromatids separate Haploid daughter cells forming

18. © 2014 Pearson Education, Inc.  ________________________________________

19. © 2014 Pearson Education, Inc.  ________________________________________ ________________________________________  ________________________________________ ________________________________________

20. © 2014 Pearson Education, Inc.  ________________________________________  ________________________________________:  ________________________________________

21. © 2014 Pearson Education, Inc. Figure 10.9a MITOSISMEIOSIS Prophase Duplicated chromosome Metaphase Anaphase Telophase 2n2n2n2n Daughter cells of mitosis Sister chromatids separate. Individual chromosomes line up. Chromosome duplication Parent cell 2n = 6 Chromosome duplication Pairs of chromosomes line up. Chiasma MEIOSIS I Prophase I Metaphase I Homologous chromosome pair Anaphase I Telophase I MEIOSIS II Homologs separate. Sister chromatids separate. Daughter cells of meiosis II nn nn Daughter cells of meiosis I

22. © 2014 Pearson Education, Inc. Figure 10.9aa MITOSISMEIOSIS Prophase Duplicated chromosome Metaphase Individual chromosomes line up. Chromosome duplication Parent cell 2n = 6 Chromosome duplication Pairs of chromosomes line up. Chiasma MEIOSIS I Prophase I Metaphase I Homologous chromosome pair

23. © 2014 Pearson Education, Inc. Figure 10.9ab MITOSIS MEIOSIS Anaphase Telophase 2n2n2n2n Daughter cells of mitosis Sister chromatids separate. Anaphase I Telophase I MEIOSIS II Homologs separate. Sister chromatids separate. Daughter cells of meiosis II nn nn Daughter cells of meiosis I

24. © 2014 Pearson Education, Inc. Figure 10.9b DNA replication Number of divisions Synapsis of homologous chromosomes Number of daughter cells and genetic composition Role in the animal body Occurs during interphase before mitosis begins One, including prophase, prometaphase, metaphase, anaphase, and telophase Does not occur Two, each diploid (2n) and genetically identical to the parent cell Enables multicellular adult to arise from zygote; produces cells for growth, repair, and, in some species, asexual reproduction Occurs during interphase before meiosis I begins Two, each including prophase, metaphase, anaphase, and telophase Occurs during prophase I along with crossing over between nonsister chromatids; resulting chiasmata hold pairs together due to sister chromatid cohesion Four, each haploid (n), containing half as many chromosomes as the parent cell; genetically different from the parent cell and from each other Produces gametes; reduces number of chromosome sets by half and introduces genetic variability among the gametes SUMMARY MeiosisMitosisProperty

25. © 2014 Pearson Education, Inc. Concept 10.4: Genetic variation produced in sexual life cycles contributes to evolution  ________________________________________

26. © 2014 Pearson Education, Inc. Origins of Genetic Variation Among Offspring  ________________________________________

27. © 2014 Pearson Education, Inc. Possible Chromosome Combinations _______________________________________ _______________________________________ _______________________________________: _______________ (_______________________________________)

28. © 2014 Pearson Education, Inc. Possible Chromosome Combinations _______________________________________

29. © 2014 Pearson Education, Inc. Figure 10.10-1 Possibility 1 Possibility 2 Two equally probable arrangements of chromosomes at metaphase I

30. © 2014 Pearson Education, Inc. Figure 10.10-2 Possibility 1 Possibility 2 Two equally probable arrangements of chromosomes at metaphase I Metaphase II

31. © 2014 Pearson Education, Inc. Figure 10.10-3 Possibility 1 Possibility 2 Two equally probable arrangements of chromosomes at metaphase I Metaphase II Daughter cells Combination 1Combination 2Combination 3Combination 4

32. © 2014 Pearson Education, Inc. or 123 combinations possible Fig. 10-7, p.161 Possible Chromosome Combinations

33. © 2014 Pearson Education, Inc. Figure 10.11-1 Prophase I of meiosis Pair of homologs Nonsister chromatids held together during synapsis Crossing over

34. © 2014 Pearson Education, Inc. Figure 10.11-2 Prophase I of meiosis Pair of homologs Chiasma Centromere TEM Synapsis and crossing over Nonsister chromatids held together during synapsis Crossing over

35. © 2014 Pearson Education, Inc. Figure 10.11-3 Prophase I of meiosis Pair of homologs Chiasma Centromere TEM Anaphase I Synapsis and crossing over Breakdown of proteins holding sister chromatid arms together Nonsister chromatids held together during synapsis Crossing over

36. © 2014 Pearson Education, Inc. Figure 10.11-4 Prophase I of meiosis Pair of homologs Chiasma Centromere TEM Anaphase I Synapsis and crossing over Breakdown of proteins holding sister chromatid arms together Anaphase II Nonsister chromatids held together during synapsis Crossing over

37. © 2014 Pearson Education, Inc. Figure 10.11-5 Prophase I of meiosis Pair of homologs Chiasma Centromere TEM Anaphase I Synapsis and crossing over Breakdown of proteins holding sister chromatid arms together Anaphase II Daughter cells Recombinant chromosomes Nonsister chromatids held together during synapsis Crossing over

38. © 2014 Pearson Education, Inc. Random Fertilization  _______________________________________  _______________________________________ (from independent assortment) _______________________________________