Major Animal Phyla Porifera Cnidaria Platyhelminthes Annelida Mollusca

Phylum Porifera sponges • • • Have no definite shape – asymmetrical; No tissues

CLASSES OF SPONGES • Class Calcarea – has calcium carbonate spicules • Class Hexactinellida

Phylum Cnidaria stinging-celled animals • • • Jellyfishes, corals, anemones Radial symmetry Two tissue

CLASSES OF CNIDARIANS • Class Hydrozoa – Hydra, Portuguese-Man -of-War, Obelia; mostly polyp or

Phylum Platyhelminthes flatworms • First animals to exhibit bilateral symmetry • Have primitive brain

CLASSES OF FLATWORMS • Class Turbellaria – free-living flatworms • Class Cestoda – tapeworms

Phylum Annelida segmented worms • Earthworms, sandworms, leeches • One-way digestive system • Have

CLASSES OF ANNELIDS • Class Oligochaeta – earthworms, bloodworms; oligo- means “few” and chaeta

Phylum Molluscasoft bodied animals • includes snails, slugs, nudibranchs, chitons, limpets, clams, oysters, squid,

CLASSES OF MOLLUSCS • Class Gastropoda – snails, slugs, conchs, nudibranchs; have either no

Phylum Arthropoda – joint-legged animals • includes insects, crustaceans, centipedes, millipedes, and arachnids •

CLASSES OF ARTHROPODS • Class Crustacea – shrimps, lobsters, crabs, crawfishes • Class Amphipoda

Mantis shrimp - Stomatopoda (thumbsplitter)

Phylum Echinodermata – spiney-skinned animals • includes sea stars, brittle stars, sea urchins, sand

WHY ARE ECHINODERMS RANKED SO HIGH? • Clues from embryology – study of the

CLASSES OF ECHINODERMS • Class Asteroidea – sea stars • Class Ophiuroidea – brittle

Phylum Chordata • Includes fish, amphibians, reptiles, birds, and mammals • Chordate characteristics: •

CHORDATE CLASSIFICATION • The Protochordates - invertebrate chordates • Subphylum Urochordata – sea squirts,

SUBPHYLUM VERTEBRATA • Class Agnatha – jawless fishes; lampreys and hagfishes • Class Chondrichthys

VERTEBRATE BODY PLAN • Recapitulation Theory – Ontogeny recapitulates Phylogeny • The embryological and

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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

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 Molluscasoft 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”; welldeveloped nervous system

Nudibranch

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

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 preexisting