Life cycles in the  excavata, chromalveolata, and Amoebozoa

Vegetative growth is associated with mitotic nuclear division followed by cell division. Cell division can be by budding, binary or multiple divisions. Each of the different groups is characterized by differences in their life cycle. The dominant vegetative phase can be haploid or diploid.

In species with a haploid life cycle, meiosis occurs at the germination of the diploid zygote.  The cells remain haploid for the rest of the vegetative phase, forming haploid gametes that fuse to form the transient diploid. Species with a diploid life history are haploid only at gamete formation. After formation of the diploid zygote they continue their life cycle as diploids until gamete formation necessitates meiosis.