Today: More Meiosis plus Asexual vs. Sexual Reproduction Discussions started this week.

For life to exist, the information (genes) must be passed on. {Mitosis: producing more cells} {Meiosis: producing gametes} Fig 13.5

extremely low genetic diversity greater genetic diversity vs. Asexual Reproduction Sexual Reproduction How does sexual reproduction generate genetic diversity? Fig 46.3

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

Fig 13.8

4 haploid cells

Fig 13.9

Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes. {Producing more cells} {Producing gametes} Fig 13.5

Different organisms have different patterns of haploid and diploid stages Fig 13.6

extremely low genetic diversity greater genetic diversity vs. Asexual Reproduction Sexual Reproduction Fig 46.3

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

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

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

Fig 29.7 Plant Evolution: different plants have different ploidy for the different parts of their life cycle.

Haploid dominant (algae) Fig Diploid dominant (fern) Fig 29.13

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

How important is genetic diversity?

Collected snails from different ponds and determined M/F ratio as well as rates of parasitism From “Biological Science” 3 rd ed. by Scott Freeman -fig 12.14

On average sexually reproducing snails were more common in areas with many parasites From “Biological Science” 3 rd ed. by Scott Freeman -fig 12.14

Does a stressful environment lead to sexual reproduction? From “Biological Science” 1 st ed. by Scott Freeman

extremely low genetic diversity greater genetic diversity Asexual Reproduction Sexual Reproduction How does sexual reproduction generate genetic diversity? Fig 46.3 Is genetic diversity critical for survival in “stressful” environments?

Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes. {Producing more cells} {Producing gametes} Fig 13.5

Today: More Meiosis plus Asexual vs. Sexual Reproduction Discussions started this week.