Porifera

Cnidaria Ctenophora Platyhelminthes Rotifera

Nematoda Nemertea Mollusca Annelida Arthropoda Bryozoa

Phoronida Brachiopoda Echinodermata Chordata

No true tissues

radial symmetry diploblastic

true tissues

Acoelomates

Deuterostomes

Bilateral symmetry triploblastic

Body cavity

Protostomes

Lophophorate phyla

Pseudocoelomates

Coelomates

A Phylogeny of the Animal Phyla

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

Ampulla

Anus Cardiac stomach

Pyloric stomach Tube foot Mouth

Ring canal

Madreporite

Radial canal

Ossicles

Ring canal

Stone canal

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

Longitudinal muscles

Circular muscles

To extend foot

1) Flex ampullar muscle 2) Relax longitudinal muscle 3) Flex 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

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

Taxa we have looked at so far

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 Worms (Amphioxus) ���

Notochord

Nerve cord

Myomeres

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

Sea Squirts - Urochordates (Tunicates)

Sea Squirts - Urochordates (Tunicates)

Sea Squirts - Urochordates (Tunicates)

Chordate Phylogeny (so far)

Urochordata (tunicates)

Cephalochordata (Amphioxus) Craniata

Chordata - Chordate Evolution

Chordates acquire over time:

1.  A distinct head - Craniates (most are extinct)

2.  A backbone

3.  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

Hagfish

Lamprey

Fibrous sheath

Notochord

Gnathostomes

Cartilage

Bone

Next time: Fish and more….