A Phylogeny of the Animal Phyla Porifera No true tissues Cnidaria radial symmetry diploblastic Ctenophora Platyhelminthes Acoelomates Rotifera Pseudocoelomates Nematoda Nemertea Mollusca Protostomes true tissues Annelida Arthropoda Bilateral symmetry triploblastic Bryozoa Lophophorate phyla Body cavity Phoronida Coelomates Brachiopoda Echinodermata Chordata Deuterostomes

Echinodermata - the starfish, urchins, sea cucumbers, sand dollars

Echinodermata - the starfish, urchins, sea cucumbers Description Echinoderms are • deuterostomes • have a water vascular system • have hardened plates (ossicles) in their epidermis • pentaradial symmetry

General anatomy of a starfish

General anatomy of a starfish Ring canal Anus Cardiac stomach Madreporite Ossicles Stone canal Pyloric stomach Ring canal Radial canal Tube foot Mouth Ampulla

Echinodermata - the starfish, urchins, sea cucumbers Water vascular system - a closed system of canals that echinoderms use for locomotion

Echinodermata - the starfish, urchins, sea cucumbers Water vascular system - a closed system of canals that echinoderms use for locomotion

Echinodermata - the starfish, urchins, sea cucumbers Water vascular system - by using water pressure echinoderms can crawl along by moving individual “tube feet” along their bodies

Echinodermata - the starfish, urchins, sea cucumbers Water vascular system - by using water pressure echinoderms can crawl along by moving individual “tube feet” along their bodies Ampullar muscles To extend foot Longitudinal muscles 1) Flex ampullar muscle 2) Relax longitudinal muscle 3) Flex circular muscles Circular muscles

Echinodermata - the starfish, urchins, sea cucumbers Ossicles

Echinodermata - Who are they? Asteroidea - Sea stars (starfish) - active predators, with small ossicles in their epidermis

Echinodermata - Who are they? Echinoidea - Sea urchins - grazers, with ossicles fused to form a test

Echinodermata - Who are they? Echinoidea - Sand dollars - grazers, with ossicles fused to form a test

Echinodermata - Who are they? Holothuroidea - Sea cucumbers - bottom feeders, with very reduced (or absent) ossicles

Taxa we have looked at so far Phylum Class Order Porifera Calcarea Demospongia Hexactinellida Platyhelminthes Turbellaria (free-living) Trematoda (flukes) Cestoda (tapeworms) Mollusca Polyplacophora (chitons) Gastropoda (snails,slugs) Bivalvia (clams, oysters) Cephalopoda (octopus, squid) Annelida Oligochaeta (earthworms) Hirudinea (leeches) Polychaeta (marine worms) Arthropoda Chelicerata (spiders, mites, scorpions) Myriapoda (centipedes, millipedes) Uniramia (insects) Crustacea (crayfish, lobsters, crabs, barnacles)

Taxa we have looked at so far Phylum Class Order Echinodermata Asteroidea (Sea stars [=starfish]) Echinoidea (sea urchins, sand dollars) Holothuroidea (sea cucumbers

Diversity of Life - Chordata-

Chordata - lancets, sea squirts, vertebrates Description Chordates are deuterostomes, with a dorsal hollow nerve cord, gill slits, a post-anal tail and a notochord

Chordata - Chordate evolution - Ancestral forms - Lancet Chordata - Chordate evolution - Ancestral forms - Lancet Worms (Amphioxus) Nerve cord Notochord Myomeres

Chordata - Chordate evolution - Ancestral forms - Lancet Chordata - Chordate evolution - Ancestral forms - Lancet Worms (Amphioxus)

Sea Squirts - Urochordates (Tunicates)

Sea Squirts - Urochordates (Tunicates)

Sea Squirts - Urochordates (Tunicates)

Chordate Phylogeny (so far) Cephalochordata (Amphioxus) Craniata Urochordata (tunicates)

Chordata - Chordate Evolution Chordates acquire over time: A distinct head - Craniates (most are extinct) A backbone Jaws

Chordata - Chordate Evolution Today

Chordata - Chordate evolution - Craniates One surviving group - hagfish - head but no backbone

Chordata - Chordate evolution - Craniates One surviving group - hagfish - Scavengers

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawless vertebrates - Agnatha - Lamprey

Chordata - Chordate evolution - Vertebrates - craniates with a backbone Jawless vertebrates - Agnatha – Lamprey - fish parasites

From Craniate to Vertebrate Fibrous sheath Notochord Hagfish Cartilage Lamprey Bone Gnathostomes

Next time: Fish and more….