Jellyfish – Life Cycle

During the life cycle of jellyfish two very different life stages alternate. The stage of polyp and the medusa. The life cycle starts by a small ciliate larva (planula), that evolved from a fertilized egg and is able to swim freely in the water. When it attaches itself to the substrate it changes into a polyp. Polyps lives solitarily or in groups and are reproducing asexually by budding (strobilation). They grow steadily and when reaching a certain size, stop producing other polyps, instead start producing freely swimming stage called ephyra. Ephyras already resemble tiny adult jellyfishes by their shape and body structure and as they grow they are slowly changing into adults. Adult jellyfishes reproduce only sexually.