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 lowgenetic diversity

greater geneticdiversity

vs.Asexual Reproduction

SexualReproduction

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

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 lowgenetic diversity

greater geneticdiversity

vs.Asexual Reproduction

SexualReproduction

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.

Haploiddominant(algae)

Fig 28.22

Diploiddominant(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” 3rd ed. by Scott Freeman -fig 12.14

On average sexually reproducing snails were more common in areas with many parasites

From “Biological Science” 3rd ed. by Scott Freeman -fig 12.14

Does a stressful environment lead to sexual reproduction?

From “Biological Science” 1st ed. by Scott Freeman

extremely lowgenetic diversity

greater geneticdiversity

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.