Vertebrate Characteristics
Kingdom Animalia; Phylum Chordata; Subphylum Vertebrata
Chordata Characteristics
Dorsal hollow nerve cordNotochord (“back cord”)Pharyngeal gill slits/arches+/- postanal tail
Subphylum Vertebrata
500 million years ago; Ordovician PeriodAbout 50,000 species known
Geologic PeriodsPALEOZOIC 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 410age of fishes; first amphibians
-Carboniferous Period 360amphibians 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 210reptiles 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 AmphioxusCompare 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 ChondrichthyesSubclass Elasmobranchii
Class ChondrichthyesSubclass Holocephali
Bony Fish
OsteichthyesGreatest number of species of vertebrates
Class Actinopterygii
Ray-finned fishOperculumBony skeletonTerminal mouthSwim bladder in most
Subclass Chondrostei - paddlefish
Subclass Chondrostei - sturgeon
Subclass NeopterygiiOrder Holostei (gar)
Subclass Neopterygiiorder Holostei - bowfin
Subclass Neopterygiidivision Teleostei
“perfect” bone95% of all fishModern cycloid or ctenoid scales
Class Sarcopterygii
Fleshy finned fish
Class SarcopterygiiSuperorder Dipnoi
Class SarcopterygiiSuperorder Crossopterygii
Latimeria = Coelocanth
Transition from water to land
Class Amphibia
Both lifeFewest numbers of speciesTerrestrial life changesMore oxygen in atmosphere than waterAir less dense than water for body supportMore temperature fluctuations
Class AmphibiaSubclass Labyrinthodontia
OLDEST TETRAPOD, about 350 myaCrossopterygian features such as dermal
scales, ray-fin tail, skull and sensory structures fish-like
GAVE RISE TO REPTILES
Class AmphibiaSubclass Lissamphibia
Smooth amphibiansMonophyletic or Diphyletic evolutionSkin with glands and keratinNo dermal scalesDouble circulatory systemEctothermicNeed water for reproduction
Subclass Lissamphibia
Order ProanuraOrder Anura
Subclass LissamphibiaOrder Urodela
Subclass LissamphibiaOrder Apoda
Class Reptilia
CreepsOrigin in mid-Carboniferous periodOrigin from labyrinthodontsAmniotesKeratinized skin with scalesStronger skeleton
Class ReptiliaSubclass AnapsidaExtinct stem reptiles
Class ReptiliaSubclass Anapsida
Class ReptiliaSubclass Lepidosauria
Class ReptiliaSubclass Archosauria
Class ReptiliaSubclass Euryapsida
Class ReptiliaSubclass Synapsida
Therapsids; ANCESTOR OF MAMMALS
Class Aves
Originated from bipedal dinosaursArchaeopteryx in Jurassic PeriodFeathersNo teeth in modern birdsEndothermicFour chambered heartComplex behavior/social organization
Class AvesSubclass Archaeornithes
Class AvesSubclass Neornithes
Class Mammalia
“breast”Originated from TherapsidsHairMammary glandsFour chambered heartDiaphragmDentary is sole lower jaw bone
Class MammaliaSubclass Prototheria
Class MammaliaSubclass Theria
Breast or PLACENTA or hair
Subclass TheriaInfraclass Metatheria
Subclass TheriaInfraclass Eutheria
Key Point: Classify Vertebrates
Gnathostome, Agnathostome
Key Point: Classify Vertebrates
Amniote, Anamniote
Key Point: Classify Vertebrates
Homeotherm/EndothermPoikilotherm/Ectotherm
Key Point: Classify Vertebrates
Fish, Tetrapod