Vertebrate Animals
(The Animals You’re Most Familiar With)
Vertebrate Animals
Phylum:
Chordata
Phylum: Chordata
• Notochord
– Supportive Longitudinal Rod (becomes a backbone in
most Vertebrates)
• Dorsal Hollow Nerve Cord
– Creasted from ectoderm infolding
• Pharyngeal Gill Slits
– Pouches or grooves along the pharynx
• Post-Anal Tail
Chordata
• Subphylum: Urochordata (Tunicates)
– Simplest & Most Ancient Chordates
– Adult is a Sessile filter-feeder
METAMORPHOSIS
– Larva is a free-swimming “tadpole”
LARVA
ADULT
Chordata
• Subphylum Urochordata (Tunicates)
Chordata
• Subphylum Cephalochordata (Lancelets)
– Both Larva & Adult are “tadpole-like”
– Neotony – retention of larval characteristics in
the adult – “juvenile” characteristics are
carried into adulthood.
• (Metamorphosis becomes less pronounced)
Chordata
• Subphylum Vertebrata (Vertebrates)
• Notochord is composed of
segments (sometimes bony
“vertebrae”), often enclosing
the dorsal hollow nerve
cord.
• “Craniates” = advanced
cephalization (formation of a
head region – a cranium).
Chordata
• Vertebrate CLASSES:
– Cephalaspidomorphi
– Placodermi
– Chondrichthyes
– Actinopterygii
– Sarcopterygii
– Dipnoi
– Amphibia
– Reptilia
• Aves
– Mammalia
(Neotony)
Chordata
• CLASS Cephalaspidomorphi (Lampreys)
– Hollow cartilage endoskeleton (with
segmented projections) surrounding a
persistent notochord.
– Jawless (Agnathostomes)
– Mostly parasitic
Chordata
• CLASS Placodermi (Placoderms)
– 1st Jawed vertebrates (Gnathostomes)
– Extinct
– Armored plates.
– Likely a cartilage endoskeleton
Chordata
• CLASS Chondrichthyes (Sharks, Rays)
– Cartilaginous Fish – Cartilage endoskeleton.
– Well-developed jaws.
– Continual swimmers (density > water)
– Placoid (tooth-like) scales (actual teeth too)
– Oviparous, Ovoviviparous, or Viviparous
Chordata
• CLASS Actinopterygii (Ray-finned Fish)
– (Osteichthyes) - bony fish (calcium phosphateenriched endoskeleton = ossified endoskeleton)
– Highly maneuverable (ray-fins)
– Swim Bladder (buoyancy control)
– Respiratory gills supported by a bony flap.
Chordata
• CLASS Sarcopterygii (Lobe-finned fish)
– Large muscular pegs within pectoral & pelvic
fins (pulled fish through mud flats).
• CLASS Dipnoi (Lung fish)
– Gulp air into rudimentary lung-like sacs.
Coelacanth (Class Actinistia)
Australian Lungfish
Chordata
• Origin of Tetrapods -- 4 limbed organisms
Bones & muscles
modified for
land motility.
Chordata
• CLASS Amphibia (Salamanders, frogs)
– Metamorphosis (“two lives”).
• Aquatic herbivorous larva (tadpole) with gills.
• Semi-aquatic or aquatic carnivorous adult,
sometimes with lungs.
– Skin often functions in gas exchange.
– Water required to complete the life cycle.
Chordata
• Origin of Amniotes – an amniotic egg
(surrounded by layers of tissue)
– allows for exclusive occupation of land.
Chordata
• CLASS Reptilia (dinosaurs, lizards, snakes,
turtles, birds)
– Skin with Keratinized scales.
– Lungs.
– Most are Ectothermic (cold-blooded).
Chordata
• …BIRDS
– Surviving Dinosaurs
– Endothermic
– Feathers are modified scales
– Bones hollow
Chordata
• CLASS Mammalia (Monotremes, Marsupials,
Placentals)
– Mammary Glands – rich nutritive milk for
offspring (increased parental care).
– Hair (modified skin).
– Endothermic.
– Diaphragm.
– Specialized dentition.
Mammals
• Monotremes (Spiny Echidna, Platypus)
– Oviparous (egg-laying)
– Australia
Mammals
• Marsupials (Kangaroo, Possum, Wombat)
– Placentals
– Viviparous (young born live, but immature)
Mammals
• Eutherians (Rodents, Elephants, Bears,
Cats, Dogs, Primates, Whales, Bats, etc.)
– Placentals
– Viviparous (young born live & relatively
mature)