Some species consist only of females with new females developing by parthenogenesis from unfertilized eggs. Other species produce two types of eggs, one that develops into females, the other into degenerate males. Males produce sperm that fertilize eggs which develop into resistant zygotes that survive desiccation. When conditions improve, the zygotes break dormancy and develop into a new female generation that reproduces by parthenogenesis until unfavorable conditions return. Rotifers have no regeneration or repair abilities.
Rotifers contain a certain and consistent number of cells as adults.
The zygotes undergo a specific number of divisions and the adult contains a fixed number of cells. Very numerous in both species and individuals. Found in fresh water, marine, moist soil, tissues of plants, and tissues and body fluids of animals. A complete digestive tract is present and nutrients are transported through the body in the pseudocoelomic fluid. A tough transparent cuticle forms the outer body covering.