Metaphase I   Shortest phase; paired homologues align. INDEPENDENT ASSORTMENT occurs  pairs of homologues line up independently of other pairs’ orientation toward the poles -- random. Adds variation. Anaphase I  Homologous chromosomes separate towards the poles (Tetrads separate)  Sister chromatids remain attached Telophase I   Each pole now has haploid set of chromosomes (however – still doubled). Cytokinesis occurs: two haploid daughter cells formed. Meiosis II   No interphase II ( no more DNA replication) Remember: Meiosis II is similar to mitosis Prophase II / Metaphase II Anaphase II Telophase II     Same as telophase in mitosis. Nuclei form. Cytokinesis occurs (2nd time). Four haploid daughter cells produced (chromosomes now back to single condition). gametes ~ sperm or egg; ovule or pollen grain Н mo о. цв,-· i11n ТЕL 1 ·th· no etween th _ ....... . · ,оп юns ► Gamete Formation in Animals  Diff. bet. male and female gametes. Male: spermatogenesis  all 4 develop into sperm cells. Female: oogenesis  cytokinesis in meiosis is uneven.  most of cytoplasm goes into 1 of the 4 meiotic products (forms large egg cell)  3 other cells are small “polar bodies”, break down (extra chrom. lost). Spermatogenesis human germ cell in testes n=23 n=23 n=23 Still doubled chromosomes 2n = 46 diploid (2n) n=23 n=23 Still doubled chromosomes n=23 meiosis I meiosis II sperm haploid (n) Oogenesis human germ cell in ovary 23 n=23 23 Still doubled 2n = 46 23 n=23 Still doubled diploid (2n) meiosis I Ovum n=23 meiosis II Polar Bodies