Biology 1001A Study Guide - Quiz Guide: Bioaccumulation, Zygote, Sporophyte
Document Summary
Lectures 9: products of meiosis in animals vs. plants, fungi and algae, meiosis in animals: zygotes divide by mitosis, gametes produced by meiosis. In plants: spores and zygotes divide by mitosis in haploid and diploid phases. In plants, the haploid products of meiosis are spores, not gametes: these spores divide by mitosis to form multicellular bodies that then make gametes by mitosis. Many organisms make gametes by mitosis: animals are haploids only as sperm and egg and fertilization restores the diploid phase of the life cycle. Immediately after fertilization, the diploid zygote undergoes meiosis to produce the haploid phase. Mitotic divisions occur only in the haploid phase: main differences between meiosis and mitosis, the essence of mitosis is sameness, but meiosis changes both chromosome number and dna sequence. Each cell produced by meiosis therefore carries only one member of the homologous pair: when an egg and sperm cell join in fertilization, the diploid number is restored.
