Haploid cells have only one copy of each chromosome. Most fungi, and a few algae exist as haploid organisms. Plants and other algae switch between a haploid and a diploid or polyploid state, with one of the stages emphasized over the other. This is called alternation of generations. Animals are primarily diploid but produce haploid gametes.
Each of these organisms produces haploid sex cells that can combine to form a diploid zygote. The zygote has genetic information from both cells and soon grows into an embryo.
