48 USE this after "Island Explorer" exercise Today’s exercise will only be concerned with the most general levels of classification – the phylum and class.  It will serve to illustrate how characteristics can be used to group related species, or to differentiate them.       The taxonomic key used in this exercise can be a guide for your study of “unknown” members of animal phyla.  It is not a complete key, since it does not list all of the taxonomic subdivisions or all of the phyla and classes.  To identify a specimen, go first to the “Key to Phyla” (ideally, work together in pairs for this exercise; one student examining the specimen for characteristics, and the other studying the Key on the website).  Scroll down through the descriptions, progressively identifying important traits of your specimen.  Once you have identified the phylum, go to the “Key to Classes”, and select the best fit for your specimen’s class.  Identify the phylum and class of as many of your specimens as possible, and submit your results on the appropriate assignment form.       The numbered sets of specimens on your table include representatives of various phyla; you will be expected to identify them as completely as possible.   Before attempting to use the key to identify groupings for any specimen, examine the animal, using the following items as a guide:             1.  Number of body openings             2.  Type of symmetry             3.  Body shape             4.  Type of outer covering             5.  Segmentation             6.  Type of appendages             7.  Number of appendages             8.  Type of skeleton; exoskeleton, endoskeleton, and/or vertebral column   KINGDOM ANIMALIA KEY TO PHYLA I.                     Unicellular A.                 generally microscopic; body functions carried out by whole animal or by organelles; great variety of body patterns; locomotion by means of pseudopodia, cilia or flagella Phylum PROTISTA II.                   Multicellular A.                 Many body openings 1.                  Symmetry radial or lacking; tissues not well defined, organs not present, body wall contains numerous pores Phylum PORIFERA B.                 One main body opening; opening serves as a mouth and anus, body layers arranged as “sac within a sac” 1.                  Symmetry radial, tentacles with stinging cells around mouth Phylum CNIDARIA 2.                  Symmetry bilateral, body flattened dorsoventrally; body wormlike, not segmented; no internal skeleton or circulatory system; free-living and parasitic members (flatworms) Phylum PLATYHELMINTHES C.                Two main body openings, mouth and anus; body layers arranged as “tube within a tube” 1.                  Radial symmetry Parts of body in fives or multiples of five; outer covering leathery or spiny; tentacles usually absent; locomotion by means of hydraulic water vascular system; endoskeleton of calcareous spiny plates bearing spines. Phylum ECHINODERMATA 2.                  Bilateral symmetry a)                 Body wormlike; no internal skeleton (1)               Unsegmented, cylindrical body usually pointed at both ends (a)               Microscopic; free-living, aquatic, cilia arranged circularly at anterior end; attached by means of tapering posterior ‘foot’ when feeding Phylum ROTIFERA (b)               Not microscopic; round, elongated body tapering to a point at both ends; no cilia; body enclosed in a tough cuticle (roundworms) Phylum NEMATODA (2)               Segmented, no jointed appendages, no internal skeleton; circulatory system present, bristles/setae present on body surface; some members have parapodia (fleshy lobes), parasitic forms have suckers (segmented worms) Phylum ANNELIDA b)                 Body shape not wormlike (1)               Not segmented; body divided into head (often reduced); ventral muscular foot (may be modified into tentacles) and dorsal visceral hump.  Bilateral symmetry may be lost in some cases due to coiling of body.  Calcareous shell usually present; may be spirally coiled piece or two valves connected by ligamentous hinge.  Shells attached laterally or composed of several pieces or plates.  Shell may be internal or absent in some members. Phylum MOLLUSCA (2)               Superficially like mollusks, but shells dorsal and ventral rather than lateral.  Few living species, all marine.  Possess lophophore (fold which bears tentacles) encircling mouth Phylum BRACHIOPODA (3)               Segmented, well developed exoskeleton; paired, jointed appendages; body divided into head, thorax, and abdomen.  Open circulatory system; highly developed muscular system. Phylum ARTHROPODA (4)               Internal skeleton; notochord in embryonic stages, replaced in higher chordates by vertebral column (backbone); dorsal hollow nerve chord; closed circulatory system Phylum CHORDATA KINGDOM ANIMALIA KEY TO CLASSES I.                     Phylum PROTISTA A.                 Locomotion by means of flagella Class MASTIGOPHORA B.                 Locomotion by means of pseudopodia Class SARCODINA C.                Locomotion by means of cilia Class CILIATA D.                No locomotor organelles Class SPOROZOA II.                   Phylum PORIFERA A.                 Sponge body has internal skeleton of calcareous (chalky) spicules (supporting structures) Class CALCARIA B.                 Sponge body has internal skeleton of siliceous material; glass-like Class HEXACTINELLIDA C.                Sponge body has internal skeleton of protein fibers Class DEMOSPONGIA III.                  Phylum CNIDARIA A.                 Animals of the hydroid type 1.                  Hydroids small; usually attached (colonial); cylindrical, saclike gastrovascular cavity, not divided by septa. Class HYDROZOA 2.                  Hydroids large, gastrovascular cavity divided into compartments by septa; sedentary; numerous brightly-colored tentacles extend like flower petals (sea anemones).  Some secrete a hard skeleton of lime (corals).  Medusa stage absent. Class ANTHOZOA B.                 Animals of the medusa type;Hydroid phase inconspicuous or absent; large, free-swimming medusae; movement by contracting and relaxing bell-shaped body. Class SCYPHOZOA IV.               Phylum PLATYHELMINTHES A.                 Cilia present, at least on ventral surface, almost entirely free-living; wormlike form Class TURBELLARIA B.                 Cilia not present, parasitic, possess thick cuticle. 1.                  Mouth and digestive tract always present..  Body usually flattened; attachment to host by one or more suckers (flukes) Class TREMATODA 2.                  Mouth and digestive tract absent, body is long, flat, ribbonlike, with hooks and suckers at anterior end  (tapeworms) Class CESTODA V.                 Phylum ANNELIDA - segmented worms A.                 Two suckers present, one at anterior end near mouth, other at posterior end; no setae; no parapodia; no tentacles; body dorsoventrally flattened, and often tapered at both ends. Class HIRUDINEA B.                 No suckers present 1.                  Parapodia always present; well defined head bearing eyes and antennae; numerous setae arising in each segment from paired parapodia.  Some crawl or swim actively, others are sedentary, living in tubes in mud or sand. Class POLYCHAETA 2.                  Parapodia absent; indistinct head, appendages absent from head region; longitudinal rows of short setae maintain traction during movement (can be felt by running finger over ventral surface) Class OLIGOCHAETA VI.               Phylum MOLLUSCA A.                 No distinct head; shell never spirally coiled 1.                  Shell (when present) not bivalve a)                 Body marked or covered on dorsal surface by a shell of eight calcareous plates; attached tenaciously to rocks by broad, flat foot; feed by rasping organ, the radula (chitons) Class POLYPLACOPHORA b)                 Long tubular shell, open at both ends, tapering to give tusklike or toothlike appearance; marine Class SCAPHOPODA 2.                  Shell bivalve - two valves connected by a ligamentous hinge.  Two valves are similar in shape and size; no radula; filter feeders. Class BIVALVA B.                 Distinct head present; shell, if present, spirally coiled 1.                  Head with one or two pairs of tentacles; eyes small if present; well developed sense organs and radula.  Species may be marine, fresh water, or terrestrial. Class GASTROPODA 2.                  Head with eight or ten long arms bearing cuplike suckers; eyes large and well developed; shell usually internal; body elongated. Class CEPHALOPODA VII.              Phylum ARTHROPODA A.                 Antennae present 1.                  Two pairs of antennae present; at least five pairs of legs; all appendages are biramous; body distinctly segmented; calcareous exoskeleton; body of two or three parts (cephalothorax and abdomen; or head, thorax and abdomen); breathing by gills, mostly aquatic Subphylum CRUSTACEA Class CRUSTACEA 2.                  One pair of antennae present; all appendages are uniramous Subphylum UNIRAMA a)                 Body composed of three main divisions - head, thorax and abdomen; only three pairs of jointed legs; wings usually present, but may be absent; terrestrial Class INSECTA b)                 Body composed of two main divisions - head and trunk; body consists of many similar segments; wings always absent (1)               Each segment bears one pair of legs; head bears three pairs of mouth parts, carnivorous (centipedes) Class CHILOPODA (2)               Each segment bears two pairs of legs; head bears two pairs of mouth parts; most are herbivorous (millipedes) Class DIPLOPODA 3.                  Antennae absent Subphylum CHELICERATA Body composed of two main divisions - cephalothorax and abdomen; abdomen is without appendages; chephalothorax bears six pairs of appendages, including one pair of chelicerae (jaws), one pair of pedipalpi (seizes prey), and four pairs of walking legs; no wings; a)                 Horseshoe shaped body with calcareous exoskeleton; marine; breathing by “gill-books” Class MEROSTOMATA b)                 Terrestrial forms; breathe by “book-lungs” Class ARACHNIDA VIII.            Phylum ECHINODERMATA A.                 Star shaped body 1.                  Arms not sharply marked off from central disc; lower surface of arms marked with a deep longitudinal groove, bearing rows of tube feet with suckers; outer surface of body studded with many short spines and skin gills Class ASTEROIDEA 2.                  Arms sharply marked off from central disc; arms long, slender, flexible, often branched; lower surface of arms without deep longitudinal groove; tube feet without suckers Class OPHIUROIDEA B.                 Body not star shaped 1.                  Body hard, globular or disc-like, without arms, have five bands of tube feet with suckers; body bears numerous spines, oral tentacles absent (sea urchins, sand dollars) Class ECHINOIDEA 2.                  Body soft; not calcareous; sausage shaped, leathery; oral tentacles present; spines absent (sea cucumbers) Class HOLOTHUROIDEA IX.               Phylum CHORDATA; subphylum VERTEBRATA A.                 Jawless mouth; long slender body Class AGNATHA B.                 Mouth with jaws 1.                  Locomotor appendages as some sort of fins; respiration by means of gills a)                 Cartilaginous skeleton Class CHONDRICHTHYES b)                 Bony skeleton; skin covered with scales Class OSTEICHTHYES 2.                  No fins; no gills a)                 Body not provided with scales, plates, feathers or hair; digits not provided with claws or nails; skin usually soft and slimy Class AMPHIBIA b)                 Body provided with scales, feathers or hair (1)               Body covered with plates or scales or both.  Digits ending with claws; locomotor appendages present or absent; when present, they are paired. Class REPTILIA (2)               Body covered with feathers or combination of feathers and scales. Class AVES (3)               Body wholly or partly provided with hair.  Mammary glands present. Class MAMMALIA