Major Animal Phyla Porifera, Cnidaria, Platyhelminthes, Annelida, Mollusca, Arthropoda, Echinodermata, and Chordata
Phylum Poriferasponges • Have no definite shape – asymmetrical; • No tissues or organs • Colony of specialized cells • Immobile • Good powers of regeneration • Skeleton of spongin and spicules
CLASSES OF SPONGES • Class Calcarea – has calcium carbonate spicules • Class Hexactinellida – glass sponges with spicules of silica • Class Demospongiae – no spicules, only spongin
Phylum Cnidariastinging-celled animals • Jellyfishes, corals, anemones • Radial symmetry • Two tissue layers with inner mesoglea • Primitive nerve net but no brain • 2-way digestive tract • Stinging cells for capturing food.
CLASSES OF CNIDARIANS • Class Hydrozoa – Hydra, Portuguese-Man-of-War, Obelia; mostly polyp or hydroid stage • Class Scyphozoa – true jellyfishes; mostly medusa stage • Class Anthozoa – corals, anemones • Class Cubozoa – box jellies
CLASS HYDROZOA Hydra
Phylum Platyhelminthesflatworms • First animals to exhibit bilateral symmetry • Have primitive brain • 3 tissue layers • Includes free-living flatworms and parasitic flatworms (tapeworms, flukes)
CLASSES OF FLATWORMS • Class Turbellaria – free-living flatworms • Class Cestoda – tapeworms • Class Trematoda - flukes
Phylum Annelidasegmented worms • Earthworms, sandworms, leeches • One-way digestive system • Have well-developed digestive and circulatory systems
CLASSES OF ANNELIDS • Class Oligochaeta – earthworms, bloodworms; oligo- means “few” and chaeta means a “bristle” or stout hair • Class Polychaeta – many bristles and parapodia (fleshly lobes to “walk” with • Class Hirudinea – leeches (most are NOT bloodsuckers)
Phylum Mollusca-soft bodied animals • includes snails, slugs, nudibranchs, chitons, limpets, clams, oysters, squid, octopus, nautilus, etc. • Either have no shell, one shell, or two shells • Many have hard mouth parts (radula in gastropods, beak in cephalopods).
CLASSES OF MOLLUSCS • Class Gastropoda – snails, slugs, conchs, nudibranchs; have either no shell or one shell; name means “stomach foot” • Class Bivalvia – clams, oysters, mussels; have two shells that hinge together • Class Polyplacophora – chitons; snail-like with 8 embedded plates on its back • Class Cephalopoda – squid, octopus, nautilus, cuttlefish; name means “head foot”; well-developed nervous system