What are the two body types of cnidarians?
There are two basic cnidarian body shapes: a polyp form, which is attached to a surface; and an upside-down free-floating form called a medusa. Some cnidarians change form at different phases of their life cycle, while others remain in one form for their entire life.
What is a polyp body form?
Polyp, in zoology, one of two principal body forms occurring in members of the animal phylum Cnidaria. The lower end of the polyp typically is adapted for attachment to a surface. The body wall consists of an ectodermal, or outer, layer and an endodermal, or inner, layer. Cross section of a generalized coral polyp.
What is Medusa form?
In biology, a medusa (plural: medusae) is a form of cnidarian in which the body is shaped like an umbrella. The other main body-form is the polyp. Medusae vary from bell-shaped to the shape of a thin disk, scarcely convex above and only slightly concave below. The medusa form of Hydrozoans are known as hydromedusae.
Does Hydra have medusa form?
When a hydra is well fed, a new bud can form every two days. Many members of the Hydrozoa go through a body change from a polyp to an adult form called a medusa, which is usually the life stage where sexual reproduction occurs, but Hydra do not progress beyond the polyp phase.
Does Hydra have medusa stage?
Unusual because in Hydra there is no medusa. Hydra can reproduce sexually. Look for ovaries near the base, testes higher on the column. Once fertilized, this egg develops a protective ornamented shell and frequently enters a stage of arrested development or dormancy.
How does a hydra die?
In the canonical Hydra myth, the monster is killed by Heracles (Hercules) as the second of his Twelve Labors. According to Hesiod, the Hydra was the offspring of Typhon and Echidna. It had poisonous breath and blood so virulent that even its scent was deadly.
What is the feature of Hydra?
Hydra is a genus that is classified under the phylum Cnidaria, they are small, multicellular, cylindrical, and fresh-water organisms. They have tiny, tube-shaped bodies that contain several tentacles on one end.
Is Hydra a plant or an animal?
Hydra, genus of invertebrate freshwater animals of the class Hydrozoa (phylum Cnidaria). The body of such an organism consists of a thin, usually translucent tube that measures up to about 30 millimetres (1.2 inches) long but is capable of great contraction.
How do you identify a hydra?
Three major criteria are used: (I) presence or absence of symbiotic algae, (2) arrangement of tentacles on buds, and ( 3) shape of the holotrichous isorhiza nematocyst. Hydra systematics are in an unsettled state.
Who was Zeus first lover?
Zeus and Metis His first and favorite lover was Metis, a Titan goddess and mother of Athena.