Major Animal Phyla Porifera, Cnidaria, Platyhelminthes, Annelida, Mollusca, Arthropoda, Echinodermata, and Chordata

Phylum Porifera sponges 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

SPONGE ANATOMY

Barrel sponge

Vase sponge

Tube sponge

Venus Flower Basket

Phylum Cnidaria stinging-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

CLASS SCYPHOZOA

Moon jelly

CLASS ANTHOZOA

Sea anemone

Aggregating anemones

Anemone

Coral polyps

Coral reef

CLASS CUBOZOA

Phylum Platyhelminthes flatworms 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

Flatworm

Flatworm

Flatworm

Tapeworm head (scolex)

Liver fluke

Phylum Annelida segmented 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)

Christmas tree worm

Feather-duster worm

Fireworm

Nereis – a polychaete

Oligochaete

Leech

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

Nudibranch

Nudibranch

Nudibranch

Chiton

Chiton

Reef Squid

Cuttlefish

Blue-ring octopus

Chambered nautilus

Triton shell

Oyster on half-shell (needs Tabasco)

Scallop

Phylum Arthropoda – joint-legged animals includes insects, crustaceans, centipedes, millipedes, and arachnids exoskeleton made of chitin must shed shell to grow

CLASSES OF ARTHROPODS Class Crustacea – shrimps, lobsters, crabs, crawfishes Class Amphipoda – small; called scuds Class Isopoda – sea lice; some are parasitic Class Stomatopoda – mantis shrimps Class Pycnogonida – sea spiders Class Merostomata – horseshoe crabs Class Cirripedia - barnacles

Bulldozer larva - Crustacea

Bulldozer

Cleaner shrimp Crustacea

Spider crab Crustacea

Crab zoea crustacea

Crab megalops

Stone crab

Hermit crab - crustacea

Amphipoda

Giant Isopod

Parasitic isopod

Ligia exotica - isopod

Mantis shrimp - Stomatopoda (thumbsplitter)

Horseshoe crab Merostomata

Sea spider- Pycnogonida

Barnacles - Cirripedia

Phylum Echinodermata – spiney-skinned animals includes sea stars, brittle stars, sea urchins, sand dollars, sea cucumbers, and crinoids reverted back to radial symmetry (radial in adults / bilateral in larvae) tube feet and water vascular system Most exhibit pentamerism

WHY ARE ECHINODERMS RANKED SO HIGH? Clues from embryology – study of the early development of animals Protostomes versus Deuterostomes Protostome – blastopore forms the mouth in all animals except echinoderms and chordates Deuterostomes – blastopore forms the anus in echinoderms and chordates

CLASSES OF ECHINODERMS Class Asteroidea – sea stars Class Ophiuroidea – brittle stars, serpent stars Class Echinoidea – sea urchins, sand dollars Class Holothuroidea – sea cucumbers Class Crinoidea – sea lilies, feather stars

Sea star - Asteroidea

Bat star - Asteroidea

Pycnopodia - Asteroidea

Brittle star - Ophiuroidea

Sea urchin - Echinoidea

Purple urchins Echinoidea

Sand dollar - Echinoidea

Sea cucumber Holothuroidea

Feather star - Crinoidea

Phylum Chordata Includes fish, amphibians, reptiles, birds, and mammals Chordate characteristics: Dorsal hollow nerve tube Notochord Pharyngeal gill slits Post anal tail

CHORDATE CLASSIFICATION The Protochordates - invertebrate chordates Subphylum Urochordata – sea squirts, salps, and ascidians Subphylum Cephalochordata – lancelets True Chordates: Subphylum Vertebrata

Tunicate - Urochordata

Tunicate - Urochordata

Salp- Urochordata

CEPHALOCHORDATE Amphioxus

SUBPHYLUM VERTEBRATA Class Agnatha – jawless fishes; lampreys and hagfishes Class Chondrichthys – cartilaginous fishes; sharks, rays, skates, chimeras Class Osteichthys – boney fishes Class Amphibia – frogs, salamanders Class Reptila – turtles, snakes, lizards, and crocodilians Class Aves – birds Class Mammalia - mammals

VERTEBRATE BODY PLAN Recapitulation Theory – Ontogeny recapitulates Phylogeny The embryological and developmental changes an organism goes through restates its evolutionary history Evolution cannot go back and change history…it can only modify what is pre-existing

Sea lamprey - Agnatha

Hagfish - Agnatha

Great white shark - Chondrichthys

Tiger shark - Chondrichthys

Manta ray - Chondrichthys

Stingray - Chondrichthys

Ratfish (Chimera)- Chondrichthys

Electric ray - Chondrichthys

Leafy sea dragon - Osteichthys

Sargassum fish - Osteichthys

Deep sea angler fish - Osteichthys

Clown anemone fish - Osteichthys

Bull dolphin - Osteichthys

Bullfrog - Amphibia

Green sea turtle Reptila

American alligator - Reptila

Osprey - Aves

Great blue heron - Aves

Humpback whales - Mammalia

Sea lion Mammalia