Vertebrate Characteristics Kingdom Animalia; Phylum Chordata; Subphylum Vertebrata

Chordata Characteristics Dorsal hollow nerve cord Notochord (“back cord”) Pharyngeal gill slits/arches +/- postanal tail

Subphylum Vertebrata 500 million years ago; Ordovician Period About 50,000 species known

Geologic Periods PALEOZOIC ERA Cambrian Period 600 mya – appearance of all major invertebrate phyla Ordovician Period 500 – appearance of vertebrates (ostracoderms) Silurian Period 440 – archaic fishes

-Devonian Period 410 age of fishes; first amphibians -Carboniferous Period 360 amphibians dominant; first reptiles -Permian Period 290 primitive reptiles, decline of early amphibians

MESOZOIC ERA (age of reptiles; 185 million yrs. duration) -Triassic Period 245 first dinosaurs, turtles, mammals -Jurassic Period 210 reptiles dominant; first birds; arc. mammals -Cretaceous Period 145 extinction large reptiles

CENOZOIC ERA (age of mammals; 65 million yrs. duration)

Key Points From the Geologic Periods page, name 3 of the most important dates & events

Origins of Vertebrates Prochordate, such as Amphioxus Compare to Ammocoete larvae

Amphioxus Larval agnathan - Ammocoetes

Vertebrate Characteristics

SUPERCLASS AGNATHA Ostracoderms

SUPERCLASS AGNATHA Cyclostomes

AgnathaAgnatha

Lampreys & Hagfishes or Slime Eels

SUPERCLASS GNATHOSTOMATA Class Acanthodii

Class Placodermi

Class Chondrichthyes Cartilaginous fish

(Chondrichthyes) Subclass Elasmobranchii

Class Chondrichthyes Subclass Elasmobranchii

Class Chondrichthyes Subclass Holocephali

Bony Fish Osteichthyes Greatest number of species of vertebrates

Class Actinopterygii Ray-finned fish Operculum Bony skeleton Terminal mouth Swim bladder in most

Subclass Chondrostei - paddlefish

Subclass Chondrostei - sturgeon

Subclass Neopterygii Order Holostei (gar)

Subclass Neopterygii order Holostei - bowfin

Subclass Neopterygii division Teleostei

“perfect” bone 95% of all fish Modern cycloid or ctenoid scales

Class Sarcopterygii Fleshy finned fish

Class Sarcopterygii Superorder Dipnoi

Class Sarcopterygii Superorder Crossopterygii

Latimeria = Coelocanth

Transition from water to land

Class Amphibia Both life Fewest numbers of species Terrestrial life changes More oxygen in atmosphere than water Air less dense than water for body support More temperature fluctuations

Class Amphibia Subclass Labyrinthodontia OLDEST TETRAPOD, about 350 mya Crossopterygian features such as dermal scales, ray-fin tail, skull and sensory structures fish-like GAVE RISE TO REPTILES

Class Amphibia Subclass Lissamphibia Smooth amphibians Monophyletic or Diphyletic evolution Skin with glands and keratin No dermal scales Double circulatory system Ectothermic Need water for reproduction

Subclass Lissamphibia Order Proanura Order Anura

Subclass Lissamphibia Order Urodela

Subclass Lissamphibia Order Apoda

Class Reptilia Creeps Origin in mid-Carboniferous period Origin from labyrinthodonts Amniotes Keratinized skin with scales Stronger skeleton

Class Reptilia Subclass Anapsida Extinct stem reptiles

Class Reptilia Subclass Anapsida

Class Reptilia Subclass Lepidosauria

Class Reptilia Subclass Archosauria

Class Reptilia Subclass Euryapsida

Class Reptilia Subclass Synapsida Therapsids; ANCESTOR OF MAMMALS

Class Aves Originated from bipedal dinosaurs Archaeopteryx in Jurassic Period Feathers No teeth in modern birds Endothermic Four chambered heart Complex behavior/social organization

Class Aves Subclass Archaeornithes

Class Aves Subclass Neornithes

Class Mammalia “breast” Originated from Therapsids Hair Mammary glands Four chambered heart Diaphragm Dentary is sole lower jaw bone

Class Mammalia Subclass Prototheria

Class Mammalia Subclass Theria Breast or PLACENTA or hair

Subclass Theria Infraclass Metatheria

Subclass Theria Infraclass Eutheria

Key Point: Classify Vertebrates Gnathostome, Agnathostome

Key Point: Classify Vertebrates Amniote, Anamniote

Key Point: Classify Vertebrates Homeotherm/Endotherm Poikilotherm/Ectotherm

Key Point: Classify Vertebrates Fish, Tetrapod