what two body plains exist in the cnidarian life cycle?
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The medusa and the polyp.
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Here is an anatomical chart for a sea urchin:\nhttp://www.carolina.com/life_science/pdfs/sea_urchin_anatomy_guide.pdf\n\nThere is an interactive dissection guide here:\nhttp://www.carolina.com/life_science/sea_urchin.asp\n\nFrom looking at these photos there appear to be two gonads, but I am not a biologist. Most of the echinoderms I work with are fossilized- except for the ones I have eaten.
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Do you mean "multi-celled"? The term "multi-celled" when applied to a plant or animal means that the organism is made up of several different cell types. The first multi-celled animals (metazoa) evolved over 600 million years ago. \n\nPrimitive metazoa can be grouped in three basic categories: sponge-like animals, cnidarians, and worms. The sponges, and cnidarians (corals and sea anemones), are the most primitive with about 11 specialized cell types. Worms and higher metazoa have approximately 55 specialized cells.\nWith the close of the Precambrian (545 mill. years ago), much of the Ediacara Biota (oldest animal-like multi-celled fossils) would become extinct. Many of them seem to be "failed experiments" in the evolution of life on Earth that became extinct just before the Cambrian "Explosion" of Life. Other Precambrian fossils do appear to be from the ancestors of modern animals. It is generally agreed that simple burrows and trace-fossils (such as Helminthopsis) found in upper Precambrian rocks were made by primitive worms. These worms, and some other members of the Ediacara Biota, survived the extinction event and took part in the greatest evolutionary event in Earth's history: The Cambrian "Explosion" of Life. Within 35 million years of the end of the Precambrian, representatives of essentially all modern phyla were present in the Cambrian seas.\n Hope that helps.
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Courtship, mating and reproduction : Like all snakes and lizards, male sea snakes have two penises. They are called hemipenes, but each is an autonomous independently functioning penis and only one is used during mating. Mating takes place for long periods and sea snakes must surface for air during that time. The female controls breathing and as she swims to the surface the male is pulled along attached via the hemipenis. At the surface the male needs to gulp for air or he has to wait til the next time the female comes up the the surface to breathe. Males are unable to disengage until mating is finished. \n\nIn species where courtship has been studied, eg olive and turtlehead sea snakes, one or more males follow the female very closely and occasionally prod the head and neck of females. \n\nAll sea snakes except the latidcaudids give birth to live young after gestation periods that range from four to eleven months, depending on the species. Most species reproduce every year. The timing of the reproductive cycle varies enomously between species and also differs between geographical locations for the same species. \n\nYoung are born underwater and must be independent immediately to swim to the surface to breathe. There is no parental care. In some species look quite different to the adults eg juvenile olive sea snake are strongly banded while the adults are not.
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Not much. They don't have "guts" like more advanced animals. They do have specialized layers of cells that do different jobs. They have a thin layer of clear "skin" that has nerve cells underneath it, so they can sense prey and predators. They also have a hollow cavity with digestive cells (sort of like a very primitive stomach) inside them. They also have muscles that control their "hydrostatic skeleton" -- basically, another hole that fills up with water, and the muscles make to pulsate so they can swim.\n\nMost of a jellyfish is water. Water is what fills up the body and gives it shape. Outside the water, it's just a blob.
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A hydra does not have a bloodstream to distribute  nutrients. Food is moved directly from one cell to another from an inner cell layer that lines the interior cavity to an outer cell layer that covers the hydra.
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In zoology it refers to organisms which have two distinct morphologic forms, where the offspring of each form is the opposite form. Typically one of the forms reproduces sexually, the other asexually. For example, some coelenterates have a free-swimming medusa (jellyfish-like) stage, and a sessile polyp (anemone-like) stage. The mature polyps reproduce asexually by budding off medusae. The medusae once mature reproduce sexually, shedding gametes into the water, and the resulting embryos settle to the bottom, attach to the substrate, and grow into polyps, which once mature produce more medusae ...
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You are looking for the Cnidaria corals I believe. In the early Paleozoic (cambrian to silurian) they diversified into tabulate corals, rugose corals, and heliolitid corals. All these forms were wiped out at the end of the Permian Period, in a mass extinction event that claimed something like 95% of all marine invertebrate species.\n\nDescriptions of these types of corals are linked in this page:\nhttp://www.ucmp.berkeley.edu/cnidaria/cnidariafr.html\n\n\nTHis page may also be a big help to you:\nhttp://www.paleoportal.org/fossil_gallery/taxon.php?taxon_id=55
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Sponges are Porifera; hydra are Cniderians.\n\nPorifera have body pores (ostia), canals and chambers that serve for passage of water. They also have choanocytes (collar cells) specialized cells that create water currents, as they are filter feeders.  \n\nCnidarians have stinging cells organelles called nematocytes or cnidocytes. They also have a nerve net with symmettrical and asymmetrical synapses.  They have a muscular system.
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Rotifers   are the only I can think of  now if it were Phylum Mollusca it could be Snails, Clams, and squids\n                                 good luck
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These steps will separate most modern animal phyla.\n\nDeveloping:\nFrom a single cell to a multi-cellular body\nFrom radial to bilateral body symmetry\nFrom spiral to radial plane of cleavage in egg division\nFrom a blastopore that forms a mouth to a blastopore that forms the anus\nFrom an incomplete digestive track to complete\nFrom no coelom, to a pseudocoel, to a true coelom\nFrom a true coelom with 2 layers to one with 3 layers\nFrom a ventral nervous system to one that is dorsal\nComplicated organ systems: excretory, circulatory, respiratory\nFrom a non-segmented body to segmentation
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The magnetic striping of the seafloor is similiar on both sides of an oceanic rift.  They match up like puzzle pieces.
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Corals: kingdom Animalia\nAlgae: not well classified, some are classified in kingdom Protista some in kingdom Plantae\nBlue-green algae: kingdom Monera\nCandida: kingdom Fungi\nRose (if you mean the flower): Kingdom Plantae
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I think the phylum name means "nettle" - it comes from the latin cnida\nthe central cavity is the spongocoel\nAnd i believe that ctenophora have colloblasts on the tenticles which burst when they come into contact with prey, releasing sticky fibres. Some just have mucus covered tenticles. Cnidaria on the other hand are your jellyfishes sometimes with masses of tenticles, and uses stinger cells.\n\nI hope this helps - i will admit marine biology is not my speciality, but I have done a bit.
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the first 1 would be frogs and the 2nd one would be lizards.....simple!!\nP.S.:thanks for the 2 points!
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echinoderms are secondarily radially symmetric whise ancestors were bilaterally symmetric.\nhence, secondary radial symmetry implies that members of a radially symmetrical group came from ancestors with bilateral symmetry.
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Cincinnaticrinus Pentagonus\n\nAn ancient Ordovician crinoid from the Cincinnati, northern Kentucky area.