Actually rad reef, when zoas repriduce asexually, they do it through meiosis, not mitosis. The difference is that in mitosis, the cell splits once and nothing is changed. During meiosis, the cell splits again, and chromatids(chunks of dna) are replaced with corresponding yet slightely different chromatids from the other half of the chromosome. This leaves four different cells, all slightely different. Over time, the differences affect not only the genotype, but the phenotype, changing the polyps color and size.
