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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
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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 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. 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)