Cyclomorphosis (also known as seasonal

polyphenism A polyphenic trait is a trait for which multiple, discrete phenotypes can arise from a single genotype as a result of differing environmental conditions. It is therefore a special case of phenotypic plasticity. There are several types of polyphen ...

) is the name given to the occurrence of cyclic or seasonal changes in the

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

of an organism through successive generations. In species undergoing cyclomorphosis, physiological characteristics and development cycles of individuals being born depend on the time of the year at which they are conceived. It occurs in small aquatic invertebrates that reproduce by

parthenogenesis Parthenogenesis (; from the Greek + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertiliz ...

and give rise to several generations annually. It occurs especially in marine planktonic animals, and is thought to be caused by the

epigenetic In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in ...

effect of environmental cues on the organism, thereby altering the course of their development.

References

Biological processes Animal physiology {{biology-stub