What is a polyp cnidarian?

What is a polyp cnidarian?

polyp, in zoology, one of two principal body forms occurring in members of the animal phylum Cnidaria. The polyp may be solitary, as in the sea anemone, or colonial, as in coral, and is sessile (attached to a surface). The lower end of the polyp typically is adapted for attachment to a surface.

Which of the cnidarians live as polyps?

The class Anthozoa includes all cnidarians that exhibit a polyp body plan only; in other words, there is no medusa stage within their life cycle. Examples include sea anemones, sea pens, and corals, with an estimated number of 6,100 described species.

Do cnidarians have a polyp stage?

Cnidarians have two body forms—polyp and medusa—which often occur within the life cycle of a single cnidarian. Sea nettle (Chrysaora fuscescens). Thus, the polyp is essentially a juvenile form, while the medusa is the adult form. In contrast, anthozoans are polypoid cnidarians and do not have a medusa stage.

Do polyps have Cnidocytes?

Cnidarians mostly have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes. Both forms have a single orifice and body cavity that are used for digestion and respiration.

What body cavity does Cnidaria have?

Cnidarian bodies have two or sometimes three layers. A gastrovascular cavity (coelenteron) has a single exterior opening that serves as both mouth and anus. Often tentacles surround the opening.

Are all polyps sessile?

Not all polyps are the same; there are several different types (inflammatory, hyperplastic, adenomatous, and villous) and two shapes, sessile and pedunculated. A sessile polyp is one that is flat and does not have a stalk.

What is the function of a polyp?

Polyps extend their tentacles, particularly at night, containing coiled stinging nettle-like cells or nematocysts which pierce and poison and firmly hold living prey paralysing or killing them.

What is the polyp in cnidarians?

The polyp is a sessile, or nonmotile, organism; well-known solitary polyps are the sea anemone and the freshwater hydra. Beside above, what is the polyp and medusa forms of cnidarians?

What are the two types of body plans in cnidarians?

Two distinct body plans are found in Cnidarians: the polyp or tuliplike “stalk” form and the medusa or “bell” form. ( (Figure)). An example of the polyp form is found in the genus Hydra, whereas the most typical form of medusa is found in the group called the “sea jellies” (jellyfish).

What is an example of a polyp?

An example of the polyp form is found in the genus Hydra, whereas the most typical form of medusa is found in the group called the “sea jellies” (jellyfish). Beside above, what is the function of a polyp?

What is the difference between Medusa and polyp form?

( (Figure) ). An example of the polyp form is found in the genus Hydra, whereas the most typical form of medusa is found in the group called the “sea jellies” (jellyfish). Polyp forms are sessile as adults, with a single opening (the mouth/anus) to the digestive cavity facing up with tentacles surrounding it.