PSYC 2000 Lecture Notes - Lecture 16: Asexual Reproduction, Sexual Reproduction, Meiosis
Document Summary
Meiosis - start with eukaryote, with two copies of every chromosome (2n) or diploid cell. It goes through two rounds of division to produce four haploid (1n) cells. The four daughter cells are genetically different with 23 chromosomes (1n) in each nucleus. The genetic material found in one sperm cell is most likely never going to be found in any other sperm cell. Asexual reproducing organism use cell cycle ending in mitosis. In the genome material of the diploid cell before meiosis, it technically has four copies of each chromosome (and even before mitosis if you think about it) Meiosis evolved to produce half of the normal # of genetic material in cells. Fertilization bw two 1n cells results in a diploid cell. Crossing over starts in end of prophase i into metaphase i. Pro: can make a lot of copies quickly and easily. Con: no variability when environment changes (natural selection) Pro: a lot of variability when environment changes.
