VertebratesEmily Reiss

Josie Jacob-DolanTori Willbanks-Roos

What makes a vertebrate a vertebrate?• Internal bony skeleton• Backbone encasing spinal column, skull-encased brain• Deuterostomes

(ex: Fish, amphibians, reptiles, birds, mammals)

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

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

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...

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

  

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" 

o These include sharks and rays

• Body structure/characteristics

 Rays vs SharksSharks• 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.

ViviparousRays•  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-

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.

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Ray vs Lobe Finned fishes

Ray:• originated in fresh water and spread to the

seas. • Some (salmon, sea–run trout) replay their

evolutionary round–trip 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 herringLobe:• rod–shaped 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

Tetrapods- Gnathostomes that have limbs and feet• Tetrapod means "four feet"• Derived characters• The Origin of Tetrapods

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• ex: Amphibians- meaning: "two lives"

• Types

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

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:o less permeable skin,

ability to use the rib cage to ventilate the lungs.

• Clade of amniotes, (lizards, snakes, turtles, crocs, birds.)• Scales: create waterproof barrier, helps prevent

dehydration • Shelled eggs on land• "Cold blooded"

o Ectothermic- Not enough metabolic heat to have much effect on body temperature. 

o Endothermic- Warmed by heat generated by metabolism. Used to maintain body temperature higher than external environment.

Reptiles!

• 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.

Birds

• Reptiles but features all  in adapted for flight.o 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 

Mammals: Amniotes that have hair and produce

milk• Mammary glands - produce

milk for offspring • Hair - retain heat

o Endothermic  • Teeth adapted for many

different foods• Bigger brains 

Synapsids• Lacked hair, laid eggs• Temporal Fenestra (holes behind eye sockets) - still

present in humans• Not true mammals but adapted mammal like

characteristics

Eutherians

Marsupials

Monotremes

• Three major lineages:

 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

Primates

• Hands and feet, digitso Opposable Thumb

• Big brains, flat faces• Three main groups of living primates:

o Lemurso Lorises and Pottos o Anthropoids

Great Apes Humans

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.