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Group Gut Coelem Metazoans x no, multiple openings no, spongocoel Cnidaria no; gastr. canal only 1 opening no Medusozoa " " Anthozoa " no, hydrostatic sk. Ctenophora complete dig. sys, true gut no Lophotrochozoa some yes, some no (primitive gut), 1 opening no (v.v. reduced) (p) blood flukes, trem blind gut (and a mouth) no (p)tapeworms, cestoda no mouth, no digestive tract no Lophophorates "U" shaped dig. tract true coelem for most Rotifers incomplete gut, complete digestive sys w 2 openings pseudocoelem yes, and complete digestive sys (m and a) very reduced Polyplacophora (chitons) yes, and complete digestive sys (m and a) very reduced Gastropoda (snails, slugs) yes, and complete digestive sys (m and a) very reduced Bivalvia (clams, scallops) yes, and complete digestive sys (m and a) very reduced Cephalopods (squid, octopus) yes, and complete digestive sys (m and a) very reduced yes, complete dig. sys (m and a) true coelem Oligochaeta (earthworms) yes, complete dig. sys (m and a) true coelem Polychaeta (marine worms) yes, complete dig. sys (m and a) true coelem Hirundinea (leaches) yes, complete dig. sys (m and a) true coelem Errantia: polychaetes yes, complete dig. sys (m and a) true coelem Ecdysozoans Arthropods true gut true coelem Chelicerates/ arachnids true gut true coelem Myriapods true gut true coelem Crustaceans true gut, "gastric mill" alimentary canal, spiral true coelem Insects (hexapoda) true gut true coelem Nematodes (roundworms) yes, complete digestive tract pseudocoelem Echinodermata true coelem Echinozoa true coelem Echinioidea true coelem Sea Urchins complete dig. sys (mouth, anus at the top) true coelem Sand Dollars complete dig. sys (mouth, bottom, anus,back) true coelem true coelem Sea Cucumber true coelem Crinoidea (sea lilies, feather stars) true coelem Echinodermata (stars) true coelem Class Asteroidea (sea stars) true coelem Pycnopodia: Sunflower Stars true coelem Crown of Thorns true coelem one opening (mouth and anus), madreporite on bottom true coelem Porifera (Sponges) Flatworms (platyhelm.) Mollusks (molluska) Annelida (segmented worms) Holothuroidea Class Ophiuroidea (brittle stars)
Hemichordata true coelem Acorn Worms true coelem Pterbranchs true coelem Gyaltsenglossus true coelem Chordata true coelem Cephalochordata true coelem Urochordata (tunicates) true coelem Vertebra (vertebrates) true coelem true coelem agnatha true coelem gnathastomes true coelem true coelem true coelem Tetrapods true coelem Amphibians true coelem Reptiles true coelem Class Aves: Birds true coelem Mammals true coelem Fish chondrichthyes osteichthyes
dorsal nerve cord, true notochord dorsal nerve cord, true notochord more complex, neural crest, myelin sheaths dorsal nerve cord, true notochord warm-blooded, hemeothermy
Evolutionary Significance Part of the original eukaryotic lineage that evolved from the unikont groups Choanoflagellates link between protists and animals Metazoans, with choanocytes as sister phyla to sponges, epithelial cells not tissues not a cnidarian because of its lack of nematocysts, complete dig. sys., and biradial sym have chiton on their bodies closely related to lophophores; ciliatedmouths, but lack the U canal and pseudocoelomates calcification like anthozoans, squishy bodies with hard parts girdle/ muscular foot acts as a suction cup, 8 overlapping plates largest molluskan class, torsion, visceral mass, operculum, gastropod only one w/o radula bc of filter feeding, head & sense poor dev., no cephalization only mollusks with a closed circ. sys, only one pair of setae per segment, poorly developed head no epidermal, chitonous setae largest group, several setae per segment (parapodia and cirri) has chiton on bodies, sister protostome to lophotrochozoan, chitonous exoskeleton that molts, segmented bodies in tagmata, paired appendages abdomen, cephalothorax, chelicerae, book lungs for gas exchange, simple eyes first animals to completely live on land; millipedes largest class of myriapoda paraphyletic, chitonous exoskeleton, possession of biramous limbs, and larval forms resp. system with air-filled tubes (tracheae), spiracles not segmented, have chiton on their eggs where deuterostoma begins, first endoskeleton, water vasc. system with tube feet and ampulla water vascular system moves from madreporite through radial canal; aristotle's lantern filter feeders, sessile madreporite on bottom, benthic and epizoic, occur in aggregates; rapid movement, urc Eumetazoan, first group with nerve, muscle and epithelial tissues (diplopastic acoelm) phylum platyhelminthes; first group to evolve a true mesoderm; cephalization metamerism, and nephridia present; mesoderm outside body and dig. sys
Tissue Types (tissues or just cells) Symmetry Development no b., amorphous or radial no tissues, coanocytic collar cells no b., amorphous or radial two embryonic cell layers (dipoplastic acoelomate) radial no b., amorphous or radial CCD biradial symmetry, 8 rows of ciliary combes (ctenes), bilateralbilateral bilateral bilateral simplest animals bilateral bilateral uses a hydrostatic skeleton bilateral seudocoelomates bilateral bilateral protostomes, hard part bilateral protostome bilateral protostome bilateral protostome bilateral protostome hollow tube-witin-tube, epidermal chitonous setae (not bilateral prosotomes bilateral prosotomes bilateral prosotomes posterior sucker, ectoparasitic bilateral prosotomes bilateral prosotomes cilia flagella, produce amoeboid sperm bilateral prosotomes bilateral prosotomes book lungs (may have been key to life on land) bilateral prosotomes bilateral prosotomes bilateral prosotomes bilateral prosotomes bilateral prosotomes endoskeleton bilateral larva, radial addeuterostomes bilateral development, bilateral retention in adult form meriodional, bilateral t deuterostomes stem from endobenthos, burrow beneath seabed radial adults deuterostomes endoskeleton; slits called lunules; spines covered in cili secondary bilateral deuterostomes deuterostomes deuterostomes deuterostomes water vascular tube feet to move deuterostomes water vascular system to move (stiff tube feet so conveyer belt rot.) deuterostomes apex predators in coral reef systems deuterostomes movement not reliant on water vasc. sys deuterostomes tripoblastic acoelomates, protonephrida, 3 tissue layers spiracles and malphighian tubules, first animals to evolve flight
deuterostomes deuterostomes deuterostomes deuterostomes bilateral deuterostomes movement by alternate contraction bilateral deuterostomes v-shaped muscle segments, adult lost many characterist.bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes he tetrapods bilateral deuterostomes m or leathery eggs bilateral deuterostomes thing system bilateral deuterostomes bilateral deuterostomes bilateral deuterostomes
endoskeleton and a spinal column strong skeleton with four limbs, reproductive mechanisms that do not desiccate breath strong skin and lungs of some species lungs and kidney, mammary glands
