Chordate Taxonomy Chordates: Single dorsal hollow nerve cord Gill slits Notochord
Jawless = class Agnatha i.e. lamprey Cartilaginous fish= class Chondrichthyes i.e. sharks and rays Bony fish = class Osteichthyes i.e. tuna and salmon Vertebrates = invade land 350 million years ago, lose support of water, 2 pairs of limbs, tetrapods (four footed) Amphibians = class Amphibia i.e. frogs, toads, and salamanders Reptiles = class Reptilia i.e. turtles, snakes, iguanas, Sea turtle = order Chelonia Birds = class Aves i.e. gulls, pelicans, and penguins Mammals = class Mammalia i.e. seals, sea otters, whales, and dolphins
Dolphin Taxonomy Kingdom Phylum Class Order Family Genus Species Anamalia Chordata Mammalia Cetacea Delphinidae Torsiops Truncatus Common name: Bottlenose dolphin
Chordate Notes Phylum - Hemichordata: share developmental characteristics of chordates and echinoderms, some have larva similar to enchinoderms. They also share feature of chorodates like nerve cord, gill slits, notochord. (acorn worms are deposit feeders similar to sea cucumbers). • Phylum- Chordata: (some are invertebrates) • nerve cord • gill slits (during part of life) • Notochord - flexible support which becomes the backbone in vertebrates • ventral heart • tail (embryo)
Most chordates notochord is surrounded or replaced by bones (vertebrate column). This separates vertebrates from invertebrates. Protochordates (invertebrate chordates) • Subphylum- Urochordata (tunicates): • Sea squirts - only sessile chordate- Look somewhat like sponge; are filter feeders, H2O in incurrent siphon expelled out excurrent siphon. When disturbed they expel H2O out both siphons Urochordate Tunicates
Larvaceans and Salps related to tunicates are important zooplankton that catch food with mucus net • Have chordate characteristics as larva.
Subphylum- Cephalochordata (lancelets): • No back bone but do have: • Nerve cord • Gill slits • Notochord Lancelets- • Fish shaped filter feeder • Only missing back bone from being vertebrate • Uses gill slits to gather organic particles
Vertebrates (Subphylum- Vertebrata) Chordates with backbone: • Share 3 characteristics of all Chordata: • Nerve cord • Gill slits • Notochord • But vertebrates have a backbone or vertebral column or spine (hollow bones called vertebrae, enclose and protect nerve cord.) Vertebrates are bilaterally symmetrical with endoskeleton. About 550 mya.
Fishes: • Class- Agnatha (Jawless fish): • Feed by rasping round mouth • Draws blood from host • Body is eel like Examples: Lampreys, hagfishes or slime eels