Phylum Chordata StringCord Common Characteristics All chordates have

Phylum Chordata “String/Cord”

Common Characteristics • All chordates have the following characteristics at some point in their life – In many vertebrates, certain features may only be present as an embryo

Common Characteristics • Pharyngeal slits – series of openings that connect the inside of the throat to the outside of the "neck". Often, but not always, used as gills • Dorsal nerve cord - bundle of nerve fibers which runs down the "back". Connects the brain with body regions/organs

Common Characteristics • notochord - cartilaginous rod running underneath, and supporting, the nerve cord. This is the “backbone” of vertebrates • post-anal tail - an extension of the body past the anal opening

3 major sub-phyla • Subphylum: Cephalochordata (head cord) – AKA Lancelets or “Amphioxus” – First animals with a spinal cord – Exclusively marine, roughly fish shaped – Can swim, but usually buried in sand with anterior end exposed – Filter feeders • Oral hood lined with cilia creates water flow • Water exits through atriopore

Lancelets or “Amphioxus”

3 major sub-phyla • Subphylum: Urochordata (tail cord) – Class: Ascidiacae (little bag) – sea squirts or Tunicates • Adults are sessile, with sac like protective tunic • Larva are free swimming with chordate feature • plankton feeders (filter feeders) – Class: Larvacea (ghost like) • Free swimming throughout life • plankton feeders (filter feeders) • as adults, they resemble larvae ascidian

Ascidiacae (Tunicates)

Larvacea (ghost like)

3 major sub-phyla – Urochordata cont… – Class – Thaliacea (luxuriance ) Sea Salps • barrel shaped • plankton feeders (filter feeders) • bioluminescent = phosphorous

Subphylum Vertebrata “joint of the spine” • Largest group of chordates (58, 000 species) • Vertebrates make up 5% of all animal species • Range in size from 0. 3” species of carp to 110’ Blue Whale. • Bilateral symmetry • Includes 7 classes

Class Agnatha – “no jaws” • Lamprey eel (sometimes parasitic to fish), Hagfish • Jawless, circular mouth, usually with retractable teeth • Notochord is a flexible cartilage rod • Lack paired appendages

Class Chondrichthyes “cartilage fish” • Sharks, rays, skates • Approx. 750 species • Skeleton is cartilage, not bone • No ribs • Paired appendages

Class Osteichthyes “bony fish” • All fish that have bony skeletons • Largest class of vertebrates (29, 000 species) • All possess gills for aquatic respiration • Largest species is Ocean Sunfish (11’, 5, 000 lb) • Dwarf Pigmy Goby is smallest (0. 59”)

Class Amphibia “dual life” • Frogs, toads, salamanders, caecilians • Approx. 6, 500 species • Adapted to life in water or on land • Most are 4 limbed • Gas exchange through lungs, gills, & skin

Class Reptilia “to creep” • Snakes, turtles, lizards, alligators • Over 8, 000 species inhabit every continent except Antarctica • All reptiles have scales • All reptiles breathe through lungs

Class Aves “flight” • 10, 000 living species of birds – Most species of all tetrapod vertebrates • Inhabit every ecosystem on Earth • All birds have feathers and wings • Sternum is keeled for attachment of flight muscles – the “wish-bone”

Class Mammalia “breast” • • Over 5, 000 species Mammary glands produce milk Hair or fur for protection Almost all give birth to live young, nourished by placenta • Able to maintain body temp. internally • Largest brains of all vertebrates