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Why do scientists think the medusa stage is the first stage of the cnidarians?
Wiki User
∙ 13y ago
I dont like doing people's homework but this was one of my questions.....so here is the answer- Polyps could have formed from larvae of mudusae that became permanentely attached to a surface.
Wiki User
∙ 13y ago
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What Organisms which typically exhibit a polyp stage and a medusa stage belong to which class of Cnidarians?
Obelia
What is the bell shaped free living stage of cnidarians called?
In a word, medusa.Linnaeus coined the term medusa in 1752, referring to the free swimming, umbrella shaped stage of jellies. His reference was to the Greek myth of Medusa, whose hair was comprised of venomous snakes that resembled the stinging tentacles typically trailing behind this form of jelly. Not all cnidarians have a medusa stage, such as anemones, corals, and stalked polyps. However, all species that do have such a stage, are included in the sub-phylum, Medusozoa.
What do the two body forms of cnidarians look like?
There are two cnidarian body shapes, the bell-shaped Medusa, whose tentacles face downward and the vase-shaped polyp, whose tentacles face upward. Cnidarians have stinging cells in their tentacles known as cnidocytes. These cells include a trigger that releases a toxin-coated stinger that paralyzes any organism that has come into contact with is. Examples of a medusa include the common jellyfish, and examples of a polyp include corals and sea anemones.
How do you spell medussa?
The word here may be Medusa, a snake-tressed gorgon of Greek mythology. The name medusa is also applied to the free-swimming stage of marine cnidarians (jellyfish, stinging nettles).
What kind of environment do cnidarians live?
Cnidarians live in an aquatic habitat where they stay their whole lives. Cnidarians also have two forms in its life cycle, the polyp is the first stage. This is like a sea anemone, basically it is anchored to the ground and must wait till it matures before evolving into its medusa form, which is like a jellyfish. Some polyp's have developed the ability to move from where they are anchored though, but it is unusual. Polyp and Medusa are found in mostly all waters, the water currents in the oceans have made it possible for them to inhabit all areas in todays oceans. There are also many different types of cnidarians.
What are the two basic forms of cnidarians?
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.
How do cnidarians survive?
Cnidarians are divided in 3 main groups: the antozoan, syphozoans and cubozoan. The anthozoans are sea anemones and coral and cubazona are jellyfish. Most do not move around, but if necessary they move to get away from predators; the ocean current carries them. But, cubazonas, such as jellyfish, propel themselves to move by opening and closing their bell slowly.
What is the mode of reproduction of medusae?
Medusa is a stage in life cycle of Cnidarians eg. Obelia in which medusae are produced by budding in blastostyl.Medusa possess sex organs i.e. testes and ovaries which produce gametes i.e. sperms and eggs which fuse to form zygote which develops in second stage of life cycle called a Polyp . Possession of two alternating stage in life cycle of Cnidarians is called Metagenesis .
What are the two body forms of cnidarians and make a sketch of each below?
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.
What 5 animals aree considered cnidarians?
Cnidarians are exclusively aquatic animals that are characterized by cnidocytes which are typically used for capturing the prey. They generally have two basic body forms; the polyp and the medusa. The polyp and medusa stages are commonly used as a classification tool. Both of these forms are radially symmetrical.The first Class is Anthozoa. This Class includes sea anemones and corals. Unlike most cnidarians, these organisms do not have a medusa stage. Next, we have the Class Scyphozoa. These are the 'true jellies' and they have a polyp and a medusa stage. This is what most people think of when they hear the term 'jellyfish'. The purple striped jelly is just one of many examples. Hydrozoa is yet another class that includes the Portuguese Man O' War and animals of the Hydra Genus. Box jellyfish belong to the class Cubozoa. These organisms are notorious for having painful stings and potent. venom and the sea wasp is one of the most famous.The taxonomy of cnidarians is still being worked with a bit but these are the generally accepted classes and some examples of the types of organisms in each. Hope this helps and sorry if the answer is too long. :)
Do cats have a larva stage?
No, they do not. Insects, amphibians, or cnidarians do.
What is the dispersive stage of sponges?
medusa, the polyp is the sessile stage
