Phylum Chordata Subphylum Urochordata Subphylum Cephalochordata Subphylum Vertebrata tunicateslancets Agnathans Fish Sharks tetrapods

Characteristics of Chordates

1 st fish Proto-vertebrate Tunicate larvae Adult tunicate lancelet Possible evolution of 1 st fish

Pikaia Burgess Shale Fauna Cambrian mya Early Chordate ancestor may have given rise to 1 st vertebrate

General Features Shared by Chordates: 1.Eukaryote 2.Multicellular 3.Bilateral- deuterstomes 4.Heterotrophic

Phylum Chordata Subphylum Urochordata - Tunicates Class Ascidiacea - Sea Squirts Solitary e.g. Styela montereyensis Colonial - in groups but with own tunic Compound Colonial - colonial with shared tunic Class Thaliacea - Salps (free swimming), planktonic Class Larvacea - Gelatinous house, planktonic

Subphylum Urochordata Subphylum Urochordata tunicate

Subphylum Urochordata = tunicate Tunicate - also called 'sea squirt' notochord is confined to the tail notochord is lost during metamorphosis into sessile adult possess pharyngeal slits Repro- sexual (hermaphroditic) & asexual (budding)

Tunicate Adult Anatomy

Tunicates: Free swimming larva: notochord present only in free-swimming larvum notochord does not extend into head larvum is free-swimming but non-feeding adult is sessile filter feeder Settled larva: Settle after brief free-swimming larvum existence. Attaches at anterior end. Metamorphosis begins. Body turns Tail, notochord, dorsal nerve cord, disappear.

Class Larvacea - planktonic Oikopleura

Jelly-like house Marine snow Class Larvacea - Gelatinous house, planktonic

Pyrosoma- bioluminescent Colonial salp Class Thaliacea - Salps (free swimming), planktonic

Class Ascidiacea - Sea Squirts

Subphylum Cephalochordata Subphylum Cephalochordata lancet Strictly marine Live buried in sand with head sticking out Filter feeders

Lancet Anatomy

Vertebrate Higher Classification  Superclass Agnatha - without jaws Class Myxini – hagfishes Class Cephalaspidomorphi – lampreys  Superclass Gnathostomata – with jaws Class Chondrichthyes – sharks, rays, chimaeras Class Actinopterygii – ray-finned fishes Class Sarcopterygii – lobe-fin fishes Class Amphibia – frogs, salamanders Class Reptilia – snakes, lizards, crocodiles Class Aves - birds Class Mammalia - mammals

Agnatha (jawless fishes) Lack: paired fins, scales, & well developed vertebrae Hagfish (slime eels) –Mucus for protection –Feed on decaying flesh Lampreys –Parasitic –Anadromous Marine adults, breed in freshwater

Class Chondrichthyes Sharks, skates, rays, chimera Subphylum Vertebrata

Heterocercal tail Two dorsal fins Paired pectorals 5-7 gill slits ureoosmotic Chondrichthyes (cartilagenous fishes)

Osteichthyes (bony fishes) Swim bladder Operculum (gill cover) Homocercal tail Scales of bony origin –Smooth cycloid –Spiny ctenoid

Intestine Adipose fin (characteristic of trout) Cut edge of operculum Swim bladder Caudal fin Lateral line Urinary bladder Pelvic fin Anus Dorsal fin Spinal cord Brain Nostril Gills Kidney Heart Liver Gonad Anal fin Stomach

Class Amphibia Characteristics Cold blooded Returns to water to breed Metamorphosis Some toxic Estivation-dry and hot Hibernation- cold 3,500 species

Class Amphibia Rana cancrivora salamander Poison arrow frog newt Mudpuppy (salamander) Coqui

Class Reptilia Characteristics Cold blooded Have scales Amniotic egg Dry skin 3 chambered heart (except crocks) 6,500 species

Class Reptilia Sea snake Marine turtle Saltwater crocodile Marine iguana

Class Aves Characteristics Warm blooded Feathers and wings Hollow bones Horny bill Lungs have air sacks Hard egg shell

Class Aves

Class Mammalia Characteristics Warm blooded Have fur or hair Suckle young 3 middle ear bones

Class Mammalia Subclasses Protheria- echidna & platypus Metatheria- marsupial Eutheria- true mammals