Which class of Cnidaria only has a polyp stage?

Which class of Cnidaria only has a polyp stage?

class Anthozoa
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.

Which class is made exclusively of polyps?

Class Hydrozoa
Class Hydrozoa Most species exhibit both polypoid and medusoid forms in their lifecycles, although the familiar Hydra has only the polyp form.

What class is a polyp?

Classes. In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species undergoing a life cycle with both a polyp stage and a medusa stage.

What is the polyp form of a cnidarian?

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 structures are similar to polyp and medusa?

Polyps and Medusae. There are two distinct cnidarian body forms: polypoid and medusoid. These are both depicted in Figure below. Both polyp and medusa forms consist of a digestive sac, the coelenteron, surrounded by two layers of tissue, the endoderm and the ectoderm.

What animal is polyps?

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).

What animals have polyps?

Coral polyps are tiny, soft-bodied organisms related to sea anemones and jellyfish. At their base is a hard, protective limestone skeleton called a calicle, which forms the structure of coral reefs. Reefs begin when a polyp attaches itself to a rock on the sea floor, then divides, or buds, into thousands of clones.

Which is an example of a polyp body type?

An example of the polyp form is Hydra spp.; perhaps the most well-known medusoid animals are the jellies (jellyfish). Medusa forms are motile, with the mouth and tentacles hanging down from an umbrella-shaped bell. Some cnidarians are polymorphic, that is, they have two body plans during their life cycle.

How many species are there in the phylum Cnidaria?

The phylum Cnidaria contains about 10,000 described species divided into two monophyletic clades: the Anthozoa and the Medusozoa. The Anthozoa include the corals, sea fans, sea whips, and the sea anemones.

Which is characteristic is shared by both cnidarians and flatworms?

Only A and B are true. Which characteristic is shared by both cnidarians and flatworms? a digestive system with a single opening Vertebrates and tunicates share a notochord and a dorsal, hollow nerve cord. One may also ask, which class of the phylum Cnidaria occurs only as a polyp? Anthozoa

What kind of body plan does a cnidarian have?

Figure 2. Cnidarians have two distinct body plans, the medusa (a) and the polyp (b). All cnidarians have two membrane layers, with a jelly-like mesoglea between them. Animals in this phylum display two distinct morphological body plans: polyp or “stalk” and medusa or “bell” (Figure 2).

How are nutrients absorbed in the Cnidaria phylum?

There is also no circulatory system, so nutrients must move from the cells that absorb them in the lining of the gastrovascular cavity through the mesoglea to other cells. The phylum Cnidaria contains about 10,000 described species divided into four classes: Anthozoa, Scyphozoa, Cubozoa, and Hydrozoa.