Meiosis is a type of cell division that produces gametes (eggs and sperm) with half the normal number of chromosomes. During meiosis in humans, the number of chromosomes is halved from 46 to 23. Meiosis involves two cell divisions and produces four haploid cells from one original diploid cell, increasing genetic variation between offspring.

1. Meiosis (pg 6)

2. Meiosis (pg 6)
• Meiosis is a special type of cell division used
only for making gametes (eggs and sperm)

3. Meiosis (pg 6)
• Meiosis is a special type of cell division used
only for making gametes (eggs and sperm)
• During meiosis, the number of chromosomes
is cut in half. For example, human cells have
46 chromosomes, while eggs and sperm have
only 23

4. Ploidy
• Most animals and plants are diploid (2N).
Diploid organisms have 2 copies of each
chromosome (one from their mom and one
from dad). These are called homologous
chromosomes.

5. Ploidy
• Most animals and plants are diploid (2N).
Diploid organisms have 2 copies of each
chromosome (one from their mom and one
from dad). These are called homologous
chromosomes.
• Eggs and sperm are haploid (N) because they
have just one copy of each chromosome

6. Phases of Meiosis
• Meiosis is like a double mitosis. The cell
divides and then divides again, making 4 cells
• P1, M1, A1, T1 then P2, M2, A2, T2

7. Meiosis Increases Variation (This is why
you are not identical to your siblings)

8. Meiosis Increases Variation (This is why
you are not identical to your siblings)
1. Homologous chromosomes line up in pairs
(Draw)

9. Meiosis Increases Variation (This is why
you are not identical to your siblings)
1. Homologous chromosomes line up in pairs
(Draw)
1. Crossing Over: Pieces of the chromatids are
exchanged, creating new combinations