Mitosis vs. Meiosis Division of body cells and sex cells.

Body cells have the same number of chromosomes as the parent cells (46-46) Sex cells have half the number of chromosomes as the parent cells (46-23)

Asexual reproduction- requires only one parent cell Sexual reproduction- requires two parent cells

Parent Cell 46 Daughter Cell 46 Mitosis

Meiosis Parent Cell 46 First Division 46 Sex Cell 23

Sexual Reproduction: Female sex cells are called eggs. Male sex cells are called sperm.

Sex cells are known as haploids because they have half of the genetic material. (Half from the egg and half from the sperm.)

Females release one egg from an ovary each month. If the egg is not fertilized, the egg will leave the body with menstruation. Average 28 day cycle.

Fertilization occurs with the union of the egg (23) and the sperm (23). The union creates a zygote (46 chromosomes). The zygote cell is a diploid (full number).

Who determines the sex of the offspring?

So… XX- female XY- male

The zygote begins to grow into an embryo by the process of mitosis or body cell division.

How do twins form? Identical Fraternal

Identical Twins Sonogram Fraternal Twins Sonogram

Siamese Twins are identical twins that have not entirely separated.

Feature:Mitosis:Meiosis: Beginning Cell-Body Cell # of cells produced-24 End product cell-Body CellSex Cell # of chromosomes-4623 Type of reproduction- Asexual