Gametes may develop without fertilization, or meiosis may substantially precede gamete formation. leading to the formation of haploid organisms, or haploid phases in the life cycles of organisms.

• 配子不经过受精也可能发育，若减数分裂先于配子形成，配子也可能发育。由于这些现象的存在，就导致单倍体生物的产生，或者在生物的生活史中逐渐变成单倍体。