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Chordata. Phylum Chordata. Subphylum Urochordata. Subphylum Cephalochordata. Subphylum Vertebrata. Agnathans Fish Sharks tetrapods. tunicates. lancets. Characteristics of Chordates. Possible evolution of 1 st fish. 1 st fish. lancelet. Proto-vertebrate. Adult tunicate.
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Phylum Chordata Subphylum Urochordata Subphylum Cephalochordata Subphylum Vertebrata Agnathans Fish Sharks tetrapods tunicates lancets
Possible evolution of 1st fish 1st fish lancelet Proto-vertebrate Adult tunicate Tunicate larvae
Early Chordate ancestor may have given rise to 1st vertebrate Pikaia Burgess Shale Fauna Cambrian 540-500 mya
General Features Shared by Chordates: • Eukaryote • Multicellular • Bilateral- deuterstomes • 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 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)
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 1800. • Tail, notochord, dorsal nerve cord, disappear.
Class Larvacea - planktonic Oikopleura
Class Larvacea - Gelatinous house, planktonic Jelly-like house Oikopleura Marine snow
Class Thaliacea - Salps (free swimming), planktonic Pyrosoma- bioluminescent Colonial salp
Subphylum Cephalochordata lancet • Strictly marine • Live buried in sand with head sticking out • Filter feeders
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
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 Agnatha (jawless fishes)
Class Chondrichthyes Subphylum Vertebrata Sharks, skates, rays, chimera
Heterocercal tail Two dorsal fins Paired pectorals 5-7 gill slits ureoosmotic Chondrichthyes (cartilagenous fishes)
Swim bladder Operculum (gill cover) Homocercal tail Scales of bony origin Smooth cycloid Spiny ctenoid Osteichthyes (bony fishes)
Swim bladder Dorsal fin Adipose fin (characteristic of trout) Caudal fin Spinal cord Brain Nostril Anal fin Cut edge of operculum Lateral line Liver Gills Anus Gonad Heart Stomach Urinary bladder Pelvic fin Kidney Intestine
Class Amphibia Characteristics • Cold blooded • Returns to water to breed • Metamorphosis • Some toxic • Estivation-dry and hot • Hibernation- cold 3,500 species
Class Amphibia Mudpuppy (salamander) newt salamander Poison arrow frog Rana cancrivora Coqui
Class Reptilia Characteristics • Cold blooded • Have scales • Amniotic egg • Dry skin • 3 chambered heart (except crocks) 6,500 species
Class Reptilia Marine iguana Saltwater crocodile Marine turtle Sea snake
Class Aves Characteristics • Warm blooded • Feathers and wings • Hollow bones • Horny bill • Lungs have air sacks • Hard egg shell
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