Chromosomes become visible, homologous chromosomes pair, chromatids undergo crossing over (recombination). Nuclear envelope breaks down.
Paired chromosomes align at equator of cell.
Members of each chromosome pair move to opposite poles of the cell.
Chromosomes uncoil, nuclei form.
Cytoplasm divides, forming two cells. In men: equal division forms two spermatocytes. In females: unequal division of cytoplasm forms egg and polar body.
Unpaired chromosomes align at the equator of the cell.
Centromeres split, daughter chromosomes pull apart.
Chromosomes uncoil, nuclear envelope forms, meiosis ends.
The failure of chromosomes to properly separate at either the first or the second division in meiosis. Results in abnormal number of chromosomes in sperm or egg. Result could be a child with an abnormal number of chromosomes.