Vertebrate Animals (The Animals You’re Most Familiar With)

Phylum: Chordata Vertebrate Animals

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 Phylum: Chordata

Chordata Subphylum: Urochordata (Tunicates) –Simplest & Most Ancient Chordates –Adult is a Sessile filter-feeder METAMORPHOSIS –Larva is a free-swimming “tadpole” ADULT LARVA

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) Chordata 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).

Vertebrate CLASSES: –Cephalaspidomorphi –Placodermi –Chondrichthyes –Actinopterygii –Sarcopterygii –Dipnoi –Amphibia –Reptilia Aves –Mammalia Chordata (Neotony)

CLASS Cephalaspidomorphi (Lampreys) –Hollow cartilage endoskeleton (with segmented projections) surrounding a persistent notochord. –Jawless (Agnathostomes) –Mostly parasitic Chordata

CLASS Placodermi (Placoderms) –1 st 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 phosphate- enriched 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. Chordata Coelacanth (Class Actinistia) Australian Lungfish

Chordata Origin of Tetrapods -- 4 limbed organisms Bones & muscles modified for land motility.

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.

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)