Which of the following is true about the phylum Cnidaria? The bodies of its members are organized around a gastrovascular cavity . ... Coral animals, like all cnidarians, have tentacles armed with batteries of stinging cells called cnidocytes.
What is true about the phylum Cnidaria?
Which of the following is true about the phylum Cnidaria? The bodies of its members are organized around a gastrovascular cavity . ... Coral animals, like all cnidarians, have tentacles armed with batteries of stinging cells called cnidocytes.
Which of the following is a true member of the phylum Cnidaria?
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.
What is not true about cnidarians?
Cnidarians are not protostomes , either. Protostomes include: arthropods (crabs, crayfish,etc.), annelids (earthworms, leeches, etc.), and molluscs (including squid, octopus, snails, slugs).
Are Cnidaria primarily filter feeders?
They are primarily filter feeders . C) They have either, or both, of two body forms: mobile polyps and sessile medusae. D) They may use a gastrovascular cavity as a hydrostatic skeleton. 8) The members of which clade in the phylum Cnidaria occur only as polyps?
What are the characteristics of phylum Cnidaria?
Phylum Cnidaria includes animals that exhibit radial or biradial symmetry and are diploblastic , meaning that they develop from two embryonic layers, ectoderm and endoderm. Nearly all (about 99 percent) cnidarians are marine species.
Why Coelenterates are called cnidarians?
Why are Coelenterates called Cnidarians? Coelenterates are called Cnidarians because they contain specialized cells called cnidoblasts . They possess stinging structures called nematocysts.
What are five characteristics of cnidarians?
- Radial symmetry.
- Diploblastic animals.
- Tissue level of organisation.
- Presence of cnidoblasts with stinging nematocysts on the tentacles.
- Polymorphism and have two body forms, i.e. polyp and medusa.
What are the two forms of cnidarians?
They have a simple body consisting of a central gut cavity surrounded by tentacles. A jelly-like substance called mesoglea lies between the outer and inner layers of the body. 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.
Which annelid classes are parasites?
Earthworms (class Oligochaeta) are familiar terrestrial members of this phylum and leeches ( class Hirudinea ) are well-known parasitic members of the phylum, most commonly found in freshwater. The polychaete worms or “bristleworms” (class Polychaeta) are the largest group in the phylum Annelida.
Which of the following is radially symmetrical?
All animals belonging to the Cnidaria (e.g. jellyfish) and Echinodermata (e.g. starfish) are radially symmetrical. And generally sessile (in their adult form).
Are bilaterally symmetric animals usually sessile?
Bilaterally symmetric animals are usually sessile.
Which body structure describes the freshwater hydra?
Which body structure describes the freshwater hydra? A hydra is best described as a sessile polyp with the mouth pointing downward .
Do sponges use active suspension feeding?
The vast majority of sessile invertebrates that colonize hard substrata are suspension feeders . These organisms include bryozoans, ascidians, hydroids, encrusting sponges, mussels, and barnacles.
What is the difference between suspension feeders and filter feeders?
Suspension-feeders, like barnacles, anemones and featherstars, use their sticky tentacles or modified legs to ‘comb’ the water for food. Filter-feeders, like sponges, clams and sea squirts, set up currents using ‘water pumping stations ‘ to suck in and filter out food particles from the water .
Which type of body plan is characteristic of members of phylum Cnidaria?
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).
