Sinh học - Chapter 28: The origins of eukaryotic diversity

Reproduction and life cycles are highly varied among protists. Mitosis occurs in almost all protists, but there are many variations in the process. Some protists are exclusively asexual or at least employ meiosis and syngamy (the union of two gametes), thereby shuffling genes between two individuals. Others are primarily asexual but can also reproduce sexually at least occasionally. Protists show the three basic types of sexual life cycles, with some other variants, too. The haploid stage is the vegetative stage of most protists, with the zygote as the only diploid cell. Many protists form resistant cells (cysts) that can survive harsh conditions.