chapter 13 meiosis and sexual life cycles. asexual reproduction: single individual is sole parent,...
TRANSCRIPT
![Page 1: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/1.jpg)
Chapter 13Meiosis and Sexual Life
Cycles
![Page 2: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/2.jpg)
Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact copies, or clones, of the parent)
13.2
![Page 3: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/3.jpg)
Sexual reproduction: Two parents give rise to offspring that have unique combinations of genes inherited from the two parents (offspring varies genetically from their siblings and their parents).
Offspring resembles their parents more than they do less closely related individuals of the same species
13.1
![Page 4: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/4.jpg)
13.3.Human karyotype.A display of condensed chromosomes displayed in pairs
Genetics:The study of heredity and hereditary variation
![Page 5: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/5.jpg)
13.4. Chromosomes in a cell with a diploid number of 6 (2n=6) or 3 homologous pair.
Each of the 6 chromosomes consist of 2 sister chromatids, joined at the centromere.
locus
![Page 6: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/6.jpg)
Fig. 13.5.Human life cycle
Fertilization and meiosis must alternate in all sexual life cycles
![Page 7: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/7.jpg)
13.6. Three types of sexual life cycles.Note alternation of meiosis and fertilization
![Page 8: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/8.jpg)
Concept 13.3:Meiosis reduces the number of chromosome sets from diploid to haploid
• Like mitosis, meiosis is preceded by the replication of chromosomes
• Meiosis takes place in two sets of cell divisions, called meiosis I and meiosis II
• The two cell divisions result in four daughter cells, rather than the two daughter cells in mitosis
• Each daughter cell has only half as many chromosomes as the parent cell
![Page 9: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/9.jpg)
Meiosis takes place in two sets of cell divisions, called meiosis I and meiosis II.
13.7. Overview of meiosis.
How meiosis reduces the number of chromosomes.
The two cell divisions result in four daughter cells, rather than the two daughter cells in mitosis.
Each daughter cell has only half as many chromosomes as the parent cell.
![Page 10: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/10.jpg)
13.8a. The meiotic division of an animal cell.Synapsis Crossing over Interkinesis
![Page 11: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/11.jpg)
13.8b. The meiotic division of an animal cell.
![Page 12: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/12.jpg)
13.9. Comparison of meiosis and mitosis.
Differences between
mitosis and meiosis II?
![Page 13: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/13.jpg)
13.9. Comparison of meiosis and mitosis.
![Page 14: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/14.jpg)
13.10. Independent assortment of homologous chromosomes in meiosis.
![Page 15: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/15.jpg)
13.11.The results of crossing over during meiosis.
![Page 16: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/16.jpg)
13.12.The results of crossing over during meiosis.
![Page 17: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/17.jpg)
13.12.The results of crossing over during meiosis.
![Page 18: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/18.jpg)
13.12.The results of crossing over during meiosis.
![Page 19: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/19.jpg)
13.12.The results of crossing over during meiosis.
![Page 20: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/20.jpg)
Example question• A cell has a diploid chromosome number of
2n = 4. We will designate these four as chromosomes A, B, C, and D. If meiosis occurred WITH the formation of homologous pairs AC and BD, and the chromosomes were then distributed randomly between the resulting cells, how many gametes could be formed?
A) 6 (AB, AC, AD, BC, BD, and CD)B) 3 (AB, BC, and CD)C) 4 (AB, AD, BC, and CD)D) 2 (AB and CD)E) 5 (AB, AC, AD, BC, and CD)
![Page 21: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/21.jpg)
15.13. Meiotic non-disjunction
Aneuploidy
![Page 22: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/22.jpg)
15.14. Alteration of chromosome structure
![Page 23: Chapter 13 Meiosis and Sexual Life Cycles. Asexual reproduction: Single individual is sole parent, passes copies of all its genes to its offspring (exact](https://reader036.vdocument.in/reader036/viewer/2022070409/56649ea05503460f94ba3e4d/html5/thumbnails/23.jpg)
Chapter 13 Review (see p.260-261)
• 13.1. Offspring acquire genes from parents by inheriting chromosomes.
• 13.2. Fertilization and meiosis alternate in sexual life cycles.
• 13.3. Meiosis reduces the number of chromosome sets from diploid to haploid.
• 13.4. Genetic variation produced in sexual life cycles contributes to evolution.