Vertebrates

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Vertebrates
Emily Reiss Josie Jacob-Dolan Tori Willbanks-Roos
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What makes a vertebrate a vertebrate?

• Internal bony skeleton
• Backbone encasing spinal column, skull-encased
  brain
• Deuterostomes
• (ex Fish, amphibians, reptiles, birds, mammals)

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Chordate- have a notochord and a dorsal, hollow
nerve cord

• Chordate vs. Vertebrate
• Notochord
• Dorsal, Hollow Nerve cord
• Pharyngeal slits and clefts
• Muscular, post- anal tail
• Somites
• Tunicates
• Ex. humans, amphioxus

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Craniates- chordates with a head

• Neural Crest
• Heart with at least 2 chambers
• Kidneys
• Evolved during the Cambrian explosion about 530
  million years ago
• Ex. human, hagfish

To be or not to be...
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Vertebrates- Craniates with a backbone

• Originally most vertebrae were cartilage
• In some cases additions to the notochord
• Most times surrounded the notochord
• Lampreys
• Ex. Humans, pteraspis
•  
•  

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Gnathostomes- Vertebrates with jaws

• Gnathostome means "jaw mouth"
•  Aquatic gnathostomes have a lateral line system
• Appear in the fossil record about 470 million
  years ago
• Placoderms-"plate-skinned"
• Acanthodians
• Chondrichthyans-"cartilage fish" ??
• These include sharks and rays
• Body structure/characteristics

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 Rays vs Sharks

• Sharks
• streamlined body, swift swimmers don't not
  maneuver very well
• movements of the trunk and the caudal (tail) fin
  help to move them
• are carnivores
• have several rows of teeth
• Oviparous vs. Ovoviviparous vs. Viviparous
• Rays
•  closely related to sharks
•  live on the bottom of the ocean
•  tails are whip-like
• -The largest sharks and rays are suspension
  feeders that consume plankton-

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Gnathostomes- Vertebrates with jaws, continued.

• Osteichthyans- "bony fish"
• Most aquatic osteichthyans control their buoyancy
  with a swim bladder.
• They are covered by a protective bony flap called
  the operculum.

page 682
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Ray vs Lobe Finned fishes

• Ray
• originated in fresh water and spread to the
  seas. 
• Some (salmon, searun trout) replay their
  evolutionary roundtrip from fresh water to
  seawater and back to fresh water during their
  life cycle.
• serve as a food source for some humans
• ex bass, trout, perch, tuna, and herring
• Lobe
• rodshaped bones surrounded by a thick layer of
  muscle in their pectoral and pelvic fins. 
• only three lineages survive today 
• ex coelacanths, lungfishes, and  those that gave
  rise to tetrapods

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Tetrapods- Gnathostomes that have limbs and feet

• Tetrapod means "four feet"
• Derived characters
• The Origin of Tetrapods

• ex Amphibians- meaning "two lives"
• Types

on page 685
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Amphibians

• Ancestors were tetrapods
• Moist skin
• Respiration gas exchange through skin and lungs 
• Have a 3-chambered heart
• Ectotherms
• Reproduction external fertilization, external
  development 
• Metamorphosis

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Amniotes- Tetrapods that have a terrestrially
adapted egg

• Amniotic egg
•  Extraembryonic membranes - specialized
  membranes, protect the embryo but not part of the
  embryo itself
• Different shells more leathery and flexible
  (slows dehydration, allows for living on land)
• Came around in the Carboniferous

• Other adaptations
• less permeable skin, ability to use the rib cage
  to ventilate the lungs.

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Reptiles!

• Clade of amniotes, (lizards, snakes, turtles,
  crocs, birds.)
• Scales create waterproof barrier, helps prevent
  dehydration 
• Shelled eggs on land

• "Cold blooded"
• Ectothermic- Not enough metabolic heat to have
  much effect on body temperature. 
• Endothermic- Warmed by heat generated by
  metabolism. Used to maintain body temperature
  higher than external environment.

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• Parareptiles- Mostly large, stocky quadrupedal
  herbivores
• Diapsids- Distinguished by pair of holes on each
  side of the skull, includes lepidosaurs and
  archosaurs.
• Lepidosaurs- Includes lizards, snakes, etc.
• Archosaurs- Includes crocodiles, alligators,
  dinosaurs, and birds.
• Pterosaurs- Winged reptile that lived during the
  time of dinosaurs.
• Dinosaurs-Member of an extremely diverse group of
  ancient reptiles varying in body shape, size, and
  habitat.
• Theropod- A member of an ancient group of
  dinosaurs that were bipedal carnivores.

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• Birds
• Reptiles but features all  in adapted for flight.
• Wings, feathers, stronger muscles, good eye sight
• Better for hunting, migrating, defense 
• Endothermic
• Flightless species - Ratites (Ostrich, Kiwi, Emu,
  etc.)
• Beaks and feet very adaptable 

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Mammals Amniotes that have hair and produce milk

• Mammary glands - produce milk for offspring
• Hair - retain heat
• Endothermic 
• Teeth adapted for many different foods
• Bigger brains 

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Marsupials

• Synapsids
• Lacked hair, laid eggs
• Temporal Fenestra (holes behind eye sockets) -
  still present in humans
• Not true mammals but adapted mammal like
  characteristics

• Three major lineages

Monotremes
Eutherians
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•  Eutherians
• "Placental mammals" because placentas are more
  complex 
• Longer pregnancies, born when fully developed
• Includes Primates 

•  Monotremes
• Have hair, produce milk (from glands)
• Lay eggs (unlike any other mammal)
• Platypus, Echidnas (spiny anteaters)

•  Marsupials
• Give birth to live young
• Embryo develops in placenta 
• Born early in development, matures in pouch

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Primates

• Hands and feet, digits
• Opposable Thumb
• Big brains, flat faces
• Three main groups of living primates
• Lemurs
• Lorises and Pottos
• Anthropoids
• Great Apes
• Humans

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Works Cited Campbell, Neil A., and Jane B.
Reece. Biology. 7th ed. San Francisco, CA
Pearson Education Inc, 2005. Print.Campbell,
Neil A., and Jane B. Reece. Biology. 7th ed. San
Francisco, CA Pearson Education Inc, 2005.
eBook.