1 / 24

Today: More Meiosis plus Asexual vs. Sexual Reproduction Discussions start(ed) this week.

Explore the process of meiosis and its role in creating genetic diversity in sexual reproduction. Discover how crossing-over and independent assortment lead to trillions of unique gametes and the importance of genetic diversity for survival in stressful environments.

bgrahm
Télécharger la présentation

Today: More Meiosis plus Asexual vs. Sexual Reproduction Discussions start(ed) this week.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Today: More Meiosis plus Asexual vs. Sexual Reproduction Discussions start(ed) this week.

  2. Fig 12.3 {Meiosis: producing gametes} For life to exist, the information (genes) must be passed on. {Mitosis: producing more cells}

  3. Each pair of chromosomes is comprised of a paternal and maternal chromosome

  4. Fig 12.13 Asexual Reproduction Sexual Reproduction vs. extremely low genetic diversity greater genetic diversity How does sexual reproduction generate genetic diversity?

  5. Fig 12.2 Crossing-over Meiosis: In humans, crossing-over and independent assortment lead to over 1 trillion possible unique gametes. (1,000,000,000,000) Meiosis I (Ind. Assort.) Meiosis II 4 Haploid cells, each unique

  6. Fig 12.4

  7. Fig 12.4 4 haploid cells

  8. Fig 12.5

  9. Fig 12.3 {Producing gametes} Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes. {Producing more cells}

  10. Different organisms have different patterns of haploid and diploid stages

  11. Asexual Reproduction genetically identical to parent (this tree can reproduce both sexually and asexually)

  12. Pros: Genetic diversity or Replace damage DNA Why does sexual reproduction exist? • Cons: • Need two individuals • Hard to find mate • Diseases/Competition

  13. Plant Evolution:different plants have different ploidy for the different parts of their life cycle. Fig 30.9

  14. Fig 30.15+.16 Haploid dominant (algae) Diploid dominant (fern)

  15. Pros: Genetic diversity or Replace damage DNA Why does sexual reproduction exist? • Cons: • Need two individuals • Hard to find mate • Diseases/Competition

  16. How important is genetic diversity?

  17. Fig 12.14 Collected snails from different ponds and determined M/F ratio as well as rates of parasitism

  18. Fig 12.14 On average sexually reproducing snails were more common in areas with many parasites

  19. Does a stressful environment lead to sexual reproduction?

  20. Fig 12.13 Is genetic diversity critical for survival in “stressful” environments? Asexual Reproduction Sexual Reproduction vs. extremely low genetic diversity greater genetic diversity

  21. Fig 27.8 Environmental changes usually occur slowly

  22. Fig 12.13 Is genetic diversity critical for survival in “stressful” environments? Asexual Reproduction Sexual Reproduction vs. extremely low genetic diversity greater genetic diversity

  23. Fig 12.3 {Producing gametes} Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes. {Producing more cells}

More Related