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---------- I I I I Meiosis 1 I I I ----------
------------ I I I I I Meiosis 2 I I I I ------------
1. INTERPHASE 1: Resting period of cell, like in mitosis. In meiosis, cell chromosomes double from 46 to 92 for the extra steps in meiosis. INTERPHASE 2: The cell has split into two and now the two new cells contain the original 46 chromosomes.
2. PROPHASE 1 & 2: The nucleus dissolves, the chromosomes coil and become visible, the homologous chromosomes move towards each other and the centrioles divide and form spindle bundles.
3. METAPHASE 1 & 2: The pairs of homologous chromosomes align in the middle of the cell and the spindle fibres attach to the chromosomes.
4. ANAPHASE 1: The homologous chromosomes are move apart, one of each pair being pulled to the opposite sides of the cell. Each cluster of chromosomes has each type of chromosome, or half the number that the parent cell had, and the paired chromatids remain together. ANAPHASE 2: Each pair of chromosomes spilts and they become two independant chromosomes, and they move to opposite sides of the cell again.
5. TELOPHASE 1 & 2: The paired chromatids uncoil and become less visible. The nuclear membrane reforms around each cluster of chromosomes and the spindles disappear, leading to cytokinesis.
Cytokinesis: The cell has split in the middle, the cytoplasm dividing between cells and each cell has the necessary orgnelles. In meiosis 1, the two cells are left with 46 chromosomes each, and in meiosis 2, the four remaining cells each have 23 chromosomes.
Disadvantages of Meiosis: - Requires two different parent cells. - Process is longer and more complex, taking more time to accomplish. - Has tendencies towards creation of abnormalities.
Advantages of Meiosis: - Introduces the variability of chromosomes from two parents, allowing for greater diversity. - Creates unique life forms.
