What is the polyp and medusa forms of cnidarians?

Asked By: Emmanouil Boven | Last Updated: 4th May, 2020
Category: medical health digestive disorders
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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.

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Also know, how are polyp and medusa forms of cnidarians similar and different?

Medusa is a mobile life cycle stage of the Cnidaria phylum, contracting with it muscular bell. Polyp have a tubular shape and are fixed at their base, with the mouth present at the other end of the tube facing the water. Medusa have a bell shape, with tentacles hanging down. Polyp do not have a manubrium.

Subsequently, question is, what is a Medusa in cnidarians? 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.

Then, what is the polyp and medusa?

polyp and medusa, names for the two body forms, one nonmotile and one typically free swimming, found in the aquatic invertebrate phylum Cnidaria (the coelenterates). The polyp is a sessile, or nonmotile, organism; well-known solitary polyps are the sea anemone and the freshwater hydra.

What are the 2 body forms of cnidarians?

Cnidaria is a phylum containing over 9,000 species found only in aquatic and mostly marine environments. All cnidarians have radial symmetrical. There are two major body forms among the Cnidaria - the polyp and the medusa. Sea anemones and corals have the polyp form, while jellyfish are typical medusae.

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Is a sea anemone a polyp or a Medusa?

Unlike jellyfish, sea anemones do not have a medusa stage in their life cycle. A typical sea anemone is a single polyp attached to a hard surface by its base, but some species live in soft sediment and a few float near the surface of the water.

How does a jellyfish reproduce explain the process and use the words polyp and medusa?

In the adult, or medusa, stage of a jellyfish, they can reproduce sexually by releasing sperm and eggs into the water, forming a planula. The polyps clone themselves and bud, or strobilate, into another stage of jellyfish life, called ephyra. It is this form that grows into the adult medusa jellyfish.

How do polyps and medusae reproduce?

polyp and medusa: Reproduction. The medusae then produce new polyps by sexual reproduction. A medusa produces eggs or sperm, which are usually shed into the water; when an egg is fertilized, it develops into a swimming larva, which eventually settles and grows into a polyp.

What is a polyp in biology?

Polyp. Definition. noun, plural: polyps. (1) (zoology) The hollow, columnar, sessile form of Cnidarians (as opposed to the medusa form) (2) (pathology) An abnormal (usually benign) pedunculated growth, protruding from a mucous membrane.

What is Nematocyst in biology?

nematocyst. noun. A capsule within specialized cells in the tentacles of cnidarians, such as jellyfish and corals, containing a barbed, threadlike tube that delivers a toxic sting to predators and prey. Related Forms: nem′a·to·cys′tic.

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.

How do polyps reproduce?

Corals can reproduce asexually and sexually
Through budding, new polyps “bud” off from parent polyps to form new colonies. Once attached, they metamorphose into a coral polyp and begin to grow, dividing in half. As more and more polyps are added, a coral colony develops and eventually begins to reproduce.

What is the function of Medusa?

The medusa form is generally small and short-lived. Its primary function is to carry out sexual reproduction and to allow the species to disperse to different locations. Hydrozoa are classified based on the presence of a membrane called the velum that lines the inside edge of the bell in the medusa forms.

Why is a jellyfish called Medusa?

A jellyfish is called a Medusa
The shape of this bell is called a medusa because it looks like the evil Medusa in Greek mythology - a woman who had offended the goddess Athena who then changed her hair into snakes and made her face so hideous it turned people into stone.

Is a jellyfish a polyp?

Corals, sea anemones and jellyfish belong to a group of animals called cnidarians. They have a simple body consisting of a central gut cavity surrounded by tentacles. 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.

Where is the Medusa on a jellyfish?

Medusa, in zoology, one of two principal body types occurring in members of the invertebrate animal phylum Cnidaria. It is the typical form of the jellyfish. The medusoid body is bell- or umbrella-shaped. Hanging downward from the centre is a stalklike structure, the manubrium, bearing the mouth at its tip.

Does Hydra have medusa stage?

Most species of hydra are less than 15 mm long (not including the tentacles). Life cycle: Cnidarians alternate between the polyp and medusa life forms. In hydra, the medusa stage is absent and polyps reproduce both sexually and asexually.

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.

How does food get into a cnidarian?

Cnidarians are carnivores, and some can also consume plant matter. They catch their food using their nematocysts or through filter feeding. Cnidarians digest their food using a primitive digestive system that contains no organs--they have a mouth (which also serves as the anus) and a gastrovascular cavity.

What cells do cnidarians use for protection?

Cnidarians contain specialized cells known as cnidocytes (“stinging cells”), which contain organelles called nematocysts (stingers). These cells are present around the mouth and tentacles, serving to immobilize prey with toxins contained within the cells. Nematocysts contain coiled threads that may bear barbs.

What are cancerous polyps?

Colorectal cancer usually begins as a "polyp," a nonspecific term to describe a growth on the inner surface of the colon. Polyps are often non-cancerous growths, but some can develop into cancer. The two most common types of polyps found in the colon and rectum include: Hyperplastic and inflammatory polyps.

What is a jellyfish polyp?

Jellyfish have a stalked (polyp) phase, when they are attached to coastal reefs, and a jellyfish (medusa) phase, when they float among the plankton. There they develop into polyps and begin to feed and grow. In spring, some of the polyps start to bud off immature jellyfish known as ephyra larvae.