Chordates and Vertebrates

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Chordates andVertebrates

• At one time in their development ALL chordates
  have
• Notochord flexible, rod-like structure along
  the back of the organism
• Postanal Tail
• Nerve cord-tubular bundle of nerves that lies
  above the notochord.
• Gill Slits paired openings located in throat
  behind mouth. Develop into gills in fish.
  Traces can be seen in embryos of many vertebrates
  INCLUDING humans!

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Vertebrates

• Have a backbone that encloses the nerve cord.
• Most are ECTOtherms internal body temp. changes
  with its surroundings (fish, amphibians,
  reptiles)
• ENDOtherms animals with constant internal body
  temp. (Birds Mammals)
• Endoskeleton internal framework of bone and
  cartilage

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7 Vertebrate groups

1. Jawless Fish
2. Cartilaginous Fish
3. Bony Fish
4. Amphibians
5. Reptiles
6. Birds
7. Mammals

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Fish

• Ectotherms
• Adaptations for water
• Gills- organs for exchanging gas
• Fins fan like structures, used for moving,
  balance, and steering
• Scales hard thin plates that cover skin,
  provides protection
• 3 classes Jawless, Cartilaginous Bony

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Jawless Fish

• Round mouths w/ long, tube-like bodies covered in
  slimy skin w/ NO scales.
• Flexible bodies made of cartilage.
• EX Lamprey Hagfish

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Lamprey
HAGFISH
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Cartilaginous Fish
Skate
difference btw skate ray

• Skeletons made of cartilage
• Movable jaws Scales
• Ex Sharks, Skates Rays

Ray
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Bony Fish

• 95 of all species of fish
• Gills protected by gill cover
• Swim Bladder
• Most have separate sexes
• Reproduce by females releasing large of eggs,
  then males swim over eggs and release sperm.
  Call this spawning.
• Form of External fertilization

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3 Classes

1. Lobe-finned Fish
2. Rayfinned fish
3. Lung fish

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Swim Bladder

• Buoyancy ability of a liquid or gas to exert an
  upward force on an object in it.
• Swim bladder allows it to adjust its density so
  it can rise or sink.
• Fills with gas-rises. Deflates-sink.

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Amphibians

• Ectothermic vertebrates that spend part of their
  life in water part on land.
• Ex Frog, toad salamander
• Greek word amphibios means double life

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Amphibian Adaptations

• Respiration
• -Moist, smooth, scaleless skin that allows gas
  to be exchanged (breathe through skin)
• -Also have small lungs to aid in breathing.
• Hibernation inactivity in winter
• Estivation inactivity in hot, dry summer
  months.
• Eggs have no shell, so they must return to water
  to lay eggs.

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Difference Between Frogs Toads

• FROGS
• smooth or slimy skin  strong, long legs  webbed
  hind feet two bulging eyes lay eggs in
  clusters

• TOADS
• warty and dry skin  stubby bodies with short
  hind legs  Most have glands on their back that
  secrete poison
• lay eggs in long chains 

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Salamanders Newts

• Long, slender bodies
• Short legs that appear to come straight out of
  their side
• Often found under dead leaves and rocks during
  the day
• Often nocturnal, feeding on worms, crustaceans
  and insects

Difference btw salamander Newt
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Amphibian Metamorphosis
-Egg -Tadpole (aka polliwog) spends its time
swimming in the water, eating and growing. Uses
gills to breathe, presence of a tail -Tadpole w/
legs tadpole sprouts legs and arms, head
becomes more distinct -Froglet stage before the
adult frog. Tail is less prominent.
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Amphibian Metamorphosis

• Metamorphosis the development of an animal from
  a larvae into an adult
• Amphibians usually complete their life cycles in
  two environments
• Larvae water
• Adult land
• Rate of metamorphosis depends on species and
  nutrients available

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Reptiles

• Ectothermic vertebrate
• Dry, Scaly skin
• Often show maternal care (take care of eggs or
  young)
• Ex. Snakes, lizards, alligators, turtles

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Adaptations for Life on Land

• Thick, dry skin covered with scales
• 4 legs with claws that hold body off ground
  (except snakes)
• Amniotic egg
• provides environment for embryo to develop
• leathery shell
• Reptiles breathe with LUNGS!

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3 Orders of Reptiles

1. Turtles
2. Crocodiles Alligators
3. Lizards Snakes

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Turtles

• Body covered by hard shell on both top bottom
• Most can withdraw partially into shell for
  protection
• Have a BEAK (no teeth)

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Crocodiles Alligators

• Crocs
• Long, slender snouts
• Both bottom (4th lower tooth) Top teeth stick
  out when jaw closed
• Found all over world
• Aggressive

• Alligators
• Broad snouts
• Only top teeth stick out, bottom teeth have spots
  to fit in so you do not see them.
• Found only in South East USA and China

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Lizards SnakesLargest group of Reptiles!

• Lizards
• Moveable eyelids
• External ears
• Legs with clawed toes

• Snakes
• No moveable eyelids, external ears, or legs with
  clawed toes
• Hear by vibrations picked up by lower jaw bone

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Venomous vs. Poisonous

• There are NO poisonous snakes!!!
• Only Venomous
• Venom must be injected into the target
• Poisonfound in skin or meatcan cause problems
  if eaten or you come in contact with it (ex Dart
  frogs)