Marine Species example essay topic

A brief description of the phylum and their classes. By Ashley Ellison I. Acanthocephalan-any of an intestinal worms lacking a digestive tract and having a proboscis bearing rows of thorn like hooks II. Annelids- any of roundish, wormlike animals having long, segmented bodies, a brain and ventral nerve cord, and a closed circulatory system, including polychaetes, oligochaetes, and leeches A. Polychaete-any marine, annelid worms, having on most segments a pair of fleshy, leg like appendages bearing numerous bristles B. Oligochaete-any of annelid worms, as the earthworm, lacking a definite head and having relatively few body bristles: found chiefly in moist soil and fresh water. Arthropoda-any of invertebrate animals with jointed legs, a segmented body, and an exoskeleton, including insects, crustaceans, arachnids, and myriapods A. Mero stomata-Members of this class have a large shield that covers the cephalothorax. The compound eyes are reduced. The second pair of appendages, the pedipalps, resemble walking legs.

They have a long, spike-like appendage called a telson that projects from the rear of their bodies. Respiration is via book gills. B. Pycnogonida-any of mostly small saltwater arthropods with very long legs attached to a relatively tiny body C. Arachnid a-any of arthropods, usually with four pairs of legs, either lungs or tracheae, a liquid diet, no antennae, simple eyes, terrestrial environment, sensory pedipalps, and a body divided into cephalothorax and abdomen, including spiders, scorpions, mites, and ticks IV. Brachiopoda-any of a member of a phylum (Brachiopoda) of marine animals with hinged upper and lower shells enclosing two arm like parts with tentacles, used for guiding minute food particles to the mouth V. Bryozoan-any of minute water animals that form branching, mosslike colonies and reproduce by budding VI. Chaetognath a-any of small, wormlike marine animals with an arrow-shaped, finned, almost completely transparent body: they feed on plankton VII. Chordata-any of animals having at some stage of development a notochord, gill slits, and a dorsal tubular nerve cord: the phylum includes the vertebrates, tunicates, and lancelets V. Cnidarian-any of invertebrate animals, mainly marine, including jellyfishes, hydrozoans, and anthozoans, characterized by stinging cells and a saclike body cavity with a single opening for ingesting food and eliminating wastes; coelenterate A. Hydrozoan-any of cnidarians having a saclike body consisting of two layers of cells, and a mouth that opens directly into the body cavity n. any animal of this class, as a hydroid or Portuguese man-of-war B. Anthozoan-any of sessile saltwater cnidarians with a dominant polyp stage, including corals, sea anemones, and gorgonian's; actinozoan C. Scyphozoan-any of sea cnidarians, consisting of jellyfishes lacking a velum IX. Ctenophore- any of sea animals with an oval, transparent, jellylike body bearing eight rows of comb like plates that aid in swimming A. Tentaculata-Members of this class typically have two feathery tentacles that can be retracted into specialized sheaths.

In some, there are smaller, secondary tentacles, and the primary tentacles are reduced. This class includes the small, oval sea gooseberries (genus Pleurobrachia), common on both Atlantic and Pacific coasts. The more flattened species of the genus Mnemiopsis, about 4 in. long (10 cm), is common on the upper Atlantic coast; it has a large mouth and feeds mainly on larval mollusks and copepods. This species is brilliantly luminescent B. Nuda-This class is represented by just one order, which contains the species Be roe. Members of this class are generally flattened in the tentacular plane, possess no tentacles, and have a heavily branched gastrovascular system X. Echinoderm ata-any of marine animals with a water-vascular system, and usually with a hard, spiny skeleton and radial body, including the starfishes and sea urchins A. Echinoid ea-of echinoderms, including the sea urchins and sand dollars B. Crinoid ea-any of echinoderms, some of which are flowerlike in form and are anchored by a stalk opposite the mouth, others of which are free-swimming n. an animal of this class, as a sea lily or feather star C. Ophiuroidea-The, or serpent stars, are so called for their long, slender, fragile arms, which are set off sharply from the circular, pentagonal, or slightly star-shaped body disk. The arms of brittle stars are flexible and appear jointed because of the conspicuous plates of the outer surface.

They bear a row of spines along each edge. In one group, the basket stars, they are repeatedly branched, forming a large mass of tentacle like limbs. Each arm contains a radial canal (or one of its branches), but it does not contain body organs. Brittle stars feed on detritus and small organisms. The mouth leads to a large saclike stomach that fills most of the body cavity. There is no intestine or anus, and solid waste is extruded through the mouth.

The stomach is folded into ten pouches, between which lie ten respiratory sacs that open by slits onto the oral surface. The cells lining the sacs have flagellae, which create a current of water moving in and out. Respiratory exchange occurs chiefly through the thin lining of the sacs. D. Holothuroidea- any of echinoderms with an elongated, flexible, wormlike body and a mouth surrounded by tentacles; sea cucumber E. Asteroid ea-Sea stars, or starfish, vary in shape from nearly circular, to pentagonal, to the familiar starlike and flowerlike forms with five or more tapering arms. The arms are extensions of the body; each contains an extension of the body cavity, a radial canal, and body organs. Each arm has an ambulacral groove on the undersurface; in the furrow of the groove is the ambulacral area, or ambulacrum, with holes for the tube feet. The margins of the groove have spines that can close over the ambulacrum.

The tip of each arm bears a tube foot that functions as a sensory receptor for chemical and vibratory stimuli, and some have a red pigment spot that serves as a simple eye. The outer surface consists of a latticework of lime ossicles, or plates, between which project thin-walled finger like extensions called papulae. The papulae and the tube feet are the principal sites of respiratory exchange. In some groups of sea stars there are also body wall projections called pedicellaria, equipped with tiny pinchers that are operated by muscles and are used to clean the body surface and capture very small prey. Sea stars crawl about on rocks or muddy bottoms, feeding on a variety of living and dead animals. Many feed largely on bivalve mollusks and are notorious as destroyers of commercial oyster beds.

There are two or more gonads in each arm; at spawning time these may nearly fill the arms. The swimming larva settles and goes through a sessile (attached) stage while changing to the adult form F. Hirudin ea-This class includes the 500 species of leeches, flattened, predacious or parasitic annelids equipped with suckers used for creeping. Leeches range in length from about 1/2 in. to 8 in. (1 cm-20 cm); most are under 2 in.

(5 cm) long. They are commonly black, brown, green, or red, and may have stripes or spots. Leeches are primarily freshwater annelids, but some live in the ocean and some in moist soil or vegetation. The majority of leeches are predators on small invertebrates; most swallow their prey whole, but some suck the soft parts from their victims. Some leeches are parasites rather than predators, and suck the body fluids of their victims without killing them.

The distinction is not sharp, as many predatory leeches take blood meals on occasion. XI. Echinorhyncha- XII. Echiura-Echiurans are marine worms that burrow into mud or sand or live in empty shells. They are found in all oceans, most commonly in littoral zones of warm waters. They are more diverse than sipunculans despite there being fewer species described.

One species is Echiurus echiurus. X. Entoprocta- any of small, mosslike aquatic invertebrates with a complete digestive tract and an anus opening near the mouth and within the circlet of oral tentacles IV. Gastrotrich a- any of minute, freshwater and marine, wormlike animals that swim by means of cilia a common species is Chaetonolus. XV. Gnathostomulids - Gnathostomulids are small, fragile and elongate in structure.

They rarely exceed 3 mm in size, and are usually between 0.5 mm and 1 mm. There may be a discrete head, neck and trunk, which tapers to a tail. Gnathostomulids have no cuticle, and possess one cilia per epidermal cell (mono ciliate). They have no circulatory system and usually no anus. The gut is a simple tube or sac. The head has a number of sensory projections and pits of cilia on the epidermis, with nervous tissue concentrated in cephalic and buccal ganglia.

The complex oral apparatus lies on the ventral surface of the head XVI. Linguatulida-a small phylum of wormlike segmented animals, having no circulatory, respiratory, or excretory systems. They are parasites in the respiratory system of some vertebrates including snakes, crocodiles, and some mammals and birds; includes some 90 living species. XVII. Mollusca-any of invertebrate animals, including the chitons, gastropods, cephalopods, scaphopods, and bivalves characterized by a soft, unsegmented body, typically enclosed wholly or in part in a mantle and a calcareous shell, and usually having gills and a foot A. Gastropods- any of mollusks having one-piece, straight or spiral shells, as snails, limpets, etc., or having no shells or greatly reduced shells, as certain slugs: most gastropods move by means of a broad, muscular, ventral foot B. Cephalopod a- any of marine mollusks having a distinct head with highly developed eyes, varying numbers of arms, with suckers, attached to the head about the mouth, and a saclike fin-bearing mantle, as an octopus, squid, or cuttlefish C. Polyplacophora-or chitons are a small class consisting entirely of marine species. Chitons are marine molluscs which are highly adapted to life in the intertidal zone.

They may be found on most rocky shores and two species, and Lepidopleurus asellus are common around the British Isles. Chitons range in size from 1-2 cm in Lepidochiton to over 30 cm in the Pacific species Crypto chiton. The shells of chitons are characteristically divided into 8 transverse, overlapping shell plates or valves. The foot is greatly expanded, forming a large flattened sole which is used not only for locomotion but also for maintaining firm contact with the rock surface. Adhesion is effected mainly by the foot under normal conditions but, when the animal is disturbed, the girdle (the soft part surrounding the shell) is also clamped down tightly onto the rock surface. D. Scaphopoda- any of mollusks that live in muddy or sandy sea bottoms and have slightly curved, tubular shells open at both ends with a long, pointed, protrusile foot at the larger end, one species is Dentalium ver nardi E. Bivalvia- any of mollusks, including mussels and clams, having a shell consisting of two valves hinged together, a species is Corbicula fluminea F. Monoplacophora-Monoplacophorans are small and have a single, cap like shell, giving them a limpet-like appearance. A number of their organs (nephridia, heart, etc.) are repeated serially, making them resemble metameric ally-arranged species such as annelids and arthropods, most live at great depths and all are marine, a species is Piling un guis G. Aplacophora-these organisms lack shells and are worm-like in body form.

They have calcareous scales or spicules in their integument. Aplacophorans lack nephridia. All are marine; around 320 species are known, mostly from the deep oceans. They can be divided into two groups (sometimes separated as Classes Caudofoveata and Solenogastres); caudofoveates are burrowers that feed on detritus and bottom-dwelling microorganisms, while soleonogasters, which also live on the bottom, feed on cnidarians XV. Nematode- any of worms, often parasites of animals and plants, with long, cylindrical, unsegmented bodies and a heavy cuticle, as the hookworm or pinworm; roundworm A. Aphasmida-Aphids but no plasmids behind mouth lips.

Most free-living. Simple, not cuticular ized excretory system, a species is Trichinella spiral is B. Phasmida- any of various stick like or leaf like insects, including the walking sticks and leaf insects XIX. Nematomorpha- any of long, thin, worms parasitic in insects when immature and free-swimming as adults; horsehair worm A. Gordioidea-A freshwater group containing most of the known species. Aquatic or terrestrial insects act as hosts for the juvenile helminths. a species is horsehair worms B. Nectonematoidea-A marine group represented by a single genus Nectonema. this uses decapod crustaceans as hosts for the juvenile helminths, a species is gordian worms XX.

Phoronida- any of unsegmented, wormlike marine animals, with a U-shaped digestive tract and a lophophore XXI. Platyhelminthes- any of flattened worms with a soft, unsegmented body and a flame cell system, as the planarians, tapeworms, or liver flukes; flatworm A. Turbellarian- any of flatworms, mostly aquatic and nonparasitic, characterized by a leaf-shaped body covered with many cilia, a species is Achoerus pachycaudatus B. Trematode- any of parasitic flatworms with one or more external, muscular suckers; fluke C. Cestode- any of parasitic flatworms, with a ribbon like body and no intestinal canal; tapeworm XXII. Protozoa- any of microscopic animals made up of a single cell or a group of more or less identical cells and living in water or as parasites, including ciliates, flagellates, rhizopods, and sporozoans A. Phytomastigophora-phyto flagellates, groups include representatives which have chloroplasts and are photosynthetic B. Rhizopod ea- any of one-celled protozoans with pseudopodia, including the amoebas, foraminifera, and myxomycetes C. Kinetofragminophora-include the free living bodonis and parasitic trypanosome's, such as a Didinium D. Polyhymenophora-an example is Bursarial E. Sporozea- any of parasitic protozoans that usually pass through phases of both sexual and asexual generation, frequently in different hosts, during which sporogenesis takes place, including the organisms that cause malaria and Texas fever F. Myosporidea- G. Zoomastigophora- H. Actinopod ea- I. Oligohymenophora- J. Piroplasmea-minute protozoans which are pyriform, rod-shaped, or amoeboid parasites of red blood cells and occasionally leukocytes. They loco mote by a sort of gliding motion and body flexing. They possess a conoid, similar to Eimeria and Toxoplasma, which is why they are placed with the sporozoa and not with the amoeba.

The life cycle is heterogenous and ticks are the usual the intermediate hosts. K. Microsporidea- XX. Pogonophora-Pogonophorans have no mouth or digestive tract, but instead appear to absorb some nutrients through the micro villi of their tentacles. However, most of their energy is apparently derived from a association with bacteria capable of oxidising hydrogen sulphide. These bacteria then use the energy thus derived to produce organic compounds from carbon dioxide.

Usually 5 - 85 cm in length and less than a millimetre in diameter, giant pogonophorans have been discovered in the deep water Pacific rift. The species Rift ia pachyptila can be up to 1.5 m long and 4 cm in diameter. XXIV. Pori fera- any of simple, aquatic, sessile animals having a porous structure and a tough, often siliceous or calcareous, skeleton A. Calvaria- B. Demospongiae-This group contains the largest, commonest and most widely distributed species. The skeleton is made of of silica, whose number of rays vary from one to four, but these may be entirely replaced in some species by fibres, and others have a mixture of spongin and spicules. There is a wide variety of form in these sponges, (branching, encrusting, etc.) and they are sometimes brightly coloured.

They are found in both marine and freshwater conditions. The bath sponge, and freshwater sponge, Spong illa belong to this group. C. Hexactinellida-The skeleton in this group of sponges is made from of silica, each spicule being 6 rated in structure and sometimes fused together to from a solid lattice. They are found as single individuals in the shape of cylinders, vases or urns, and some have a branching form. All these sponges are marine, usually living in deep, cold waters, where they anchor onto the soft sea bed by large rooting tufts of spicules. A species is Euplectella. D. Sclerospongiae-These sponges have a skeleton constructed from calcium carbonate, silica and. They have a thin, living layer covering a massive underlying skeleton of aragonite-silica and spongin which support the cells.

These are the coralline sponges, which are mostly known from fossils. There are a few modern species, such as sclerospongia. XXV. Priapulida-consisting of 17 species of predatory, unsegmented marine worms that live in the sand and mud at the sea bottom. The largest are 4 to 6 in. (10-17 cm) long, but the majority of species are less than.

05 in. (. 13 cm) in size. The animals consist of a spiny body with an anterior that can be everted or inverted into the trunk for locomotion or feeding.

Spines around the mouth and in the phar nyx are everted to capture prey. The sexes are separate and the egg is fertilized externally, hatching into a larval stage in all but one species. Fossil species can be traced to the Cambrian period, but zoologists do not agree on an interpretation of the lining of the body cavity. This would determine if priapulids are coelo mates or pseudocoelomates. A species is meiofaunal. XXVI.

Rhyncocoela- Members of the phylum Nemertean (or Rhyncocoela), are often called ribbon worms on account of their shape. They are also sometimes called 'bootlace worms'. They are mainly marine forms and some can be highly coloured. The body plan is acoelomate but there is a body cavity - the rhynchocoel - in which the ever sible proboscis lies.

A few species are found in moist soil and freshwater habitats but the majority are marine. Although very similar to Platyhelminthes there are some important differences - the digestive tract is complete, with an anus, allowing the excretion of waste. Nemerteans are also more advanced in having a circulatory system. A species is Emplectonema. A. Ano pla-lack stylets on proboscis; mouth is posterior to brain B. Enola-possess stylets on proboscis; mouth is anterior to brain XXVII.

Rotifer a- any of microscopic invertebrate animals found mostly in fresh waters, having one or more rings of cilia at the front end of the body that, when vibrated, resemble rotating wheels A. Digononta-Digononta are distinguished by having paired gonads. All freshwater species are in the order Bdelloidea., in which all species are parthenogenetic and males do not occur. Most species attain a length of only 0.1-0.5 mm, but the largest may exceed 1 mm. B. Monogonta-Monogononta have a single gonad. The class contains three orders and all three occur in Australian inland waters.

Most species are microscopic but the largest may exceed 1 mm. Macroscopic colonies or aggregations are not uncommon. Most individuals are female, the males rare or seasonal in many species and unknown in others. Males tend to be smaller than females, and often have a reduced digestive system. XXV. Sipunculidea- XXIX.

Tardigrade- any of minute water animals with segmented bodies and four pairs of unsegmented legs, often regarded as primitive arthropods.