Hydra - the polyp, anchored with a stalk, tentacles up; and medusa, the jellyfish, swimming free, tentacles down. All cnidarians have both stages, like larva and adult, but they spend more time in one of them and are known as that stage, for example anemones and jellyfish. Anemones have a tiny jellyfish dispersal stage, and jellyfish have a tiny polyp reproduction stage.
The body systems that cnidarians have take two forms. The main body forms are medusa and polyp. Cnidarians do not have a transport system and the body surface is used for gaseous exchange.
gugu
The two body forms of cnidarians are the polyp and the medusa. Polyps are typically sessile, tube-shaped organisms attached to a substrate, while medusae are free-swimming, umbrella-shaped organisms.
Cnidarians are segmented into two main classes: Anthozoa (sea anemones and corals) and Medusozoa (jellyfish and hydrozoans), based on their body forms. Anthozoa are generally sedentary, with a polyp body form, while Medusozoa are typically free-swimming with a medusa body form.
No. Cnidarians do not have teeth or any hard body parts.
Polymorphism in cnidarians, such as having different body forms like medusae and polyps, allowed for niche differentiation and exploitation. This increased the ecological diversity within the group, facilitating adaptive radiation into various habitats and lifestyles. These different forms allowed cnidarians to occupy different ecological niches, promoting speciation and diversification.
like spokes on a wheel
Both forms have a single Body_orificeand body cavity that are used for digestion and Respiration_(physiology), so yes, cnidarians do have a respiratory system.
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No. Cnidarians don't even have a circulatory system.