Are cnidarians invertebrates?
Cnidarians are invertebrates such as jellyfish and corals. They belong to the phylum Cnidaria.
What are cnidarians related to?
Cnidarian, also called coelenterate, any member of the phylum Cnidaria (Coelenterata), a group made up of more than 9,000 living species. Mostly marine animals, the cnidarians include the corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans.
How do cnidarians differ from all other animals?
Cnidarians are distinguished from all other animals by having cnidocytes that fire harpoon like structures and are usually used mainly to capture prey. In some species, cnidocytes can also be used as anchors.
What are 4 functions of nematocysts?
Nematocysts are the means by which coelenterates capture prey and defend against predation. The 25 or more known types of nematocysts can be divided into to four functional categories: those that pierce, ensnare, or adhere to prey, and those that adhere to the substrate.
What is the difference between the two body forms exhibited by cnidarians give examples?
What is the difference between the two body forms polyp and medusa exhibited by cnidarians? Polyps are sessile and asexually reproduce by budding. But, medusa reproduces sexually by producing sperms and eggs. The key difference between polyp and medusa is that polyp is sessile whereas medusa is free-swimming.
What is the biggest difference between the two body forms of cnidarians?
Class Cubozoa A prominent difference between the two classes is the arrangement of tentacles. The cubozoans contain muscular pads called pedalia at the corners of the square bell canopy, with one or more tentacles attached to each pedalium. In some cases, the digestive system may extend into the pedalia.
Why is Scyphozoan Medusa called jellyfish?
The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or “true jellies”). The class name Scyphozoa comes from the Greek word skyphos (σκύφος), denoting a kind of drinking cup and alluding to the cup shape of the organism.
What are the two basic body forms of Coelenterata?
A Cnidarian can have one of two basic body types, polypoid or medusoid.
How do Cnidaria move?
They contract their hollow, saucer-shaped bodies (called bells) to force water out, which propels them forward. Their long. tentacle-like arms, which trail out behind them, are used to sting and capture prey.
What are the two stages in the cnidarian life cycle?
Cnidarians all have a life cycle of two forms. One is a free-swimming jellyfish medusa stage and the second is an attached polyp stage.
What is a planula?
Planula, plural planulae, free-swimming or crawling larval type common in many species of the phylum Cnidaria (e.g., jellyfish, corals, and sea anemones). The planula larva of coelenterates has an elongated shape and cilia covering its entire surface.
How is a planula formed?
The planula is the first larval stage of Aurelia, and is formed soon after the egg and sperm combine to form a zygote. The planula is lined with cilia and eventually settles, forming a scyphistoma. Planula larval stages are common to many Cnidarians.
What is the difference between planula and Amphiblastula?
Complete answer: Planula is the ciliated, bilaterally symmetrical, flattened, free swimming larva of organisms in the phylum Cnidaria. Amphiblastula is the free swimming larva of certain sponges.
What is the function of Mesoglea in jellyfish?
The mesoglea may be thinner than either of the cell layers in smaller coelenterates like a hydra or may make up the bulk of the body in larger jellyfish. The mesoglea serves as an internal skeleton, supporting the body. Its elastic properties help restore the shape after it is deformed by the contraction of muscles.
What is the meaning of mesoglea?
: a gelatinous substance between the endoderm and ectoderm of sponges or cnidarians.