2. Vertebrates
• Everything up till now has been Invertebrates
– What does this mean?
• From now on all Fishes, reptiles, birds and
mammals are all Vertebrates
– What does this mean?
• Can you think of some functions of Vertebrae
that are advantageous?
– Support
– Attachment of muscles= increased movement
3. Primitive Fish
• Class Myxini (hagfish) and Cephalospidomorphi
(lampreys)
– Lack jaws and paired appendages (fins in fish)
– Lack scales and muscles (all cartilage)
Only living representatives of primitive fish
4. Class Chondrichthyes
• Sharks, Skates, and Rays
– Defining characteristics
• Skeletons composed of cartilage
• Jaws
• Paired fins
• Placoid scales
5. Sharks!!!!!
• Streamlined body shape
• Heterocercal tail
• Two dorsal fins
• Paired pectoral fins
• Paired pelvic fins
– Modified in males (claspers) to transfer sperm
6. Why do sharks have to “just keep
swimming”?
• Has to do with Density!!!!
– The are denser than the water so what will
happen if they stop swimming?
7. Osmoregulation
• Maintain homeostasis
– By holding large amounts of urea in body
– If they did not have this adaptation they would
lose body water.
• Then what would happen to the shark
– Dehydrate and cells would………
» Shrink -> remember osmosis chapter?????
– http://dsc.discovery.com/videos/the-ultimate-
guide-to-sharks-how-sharks-swim.html
8. Sensory in Sharks
• Sight
– Lack eyelids
– Scientists predict that they can see color, but what
sense is most dominant in shark?
• Smell!!!!
– 2/3 of cells in brain are used to process sense of smell
– Can detect 1 drop of blood in 1 million parts of water
– http://dsc.discovery.com/videos/ultimate-guide-the-
sharks-shark-smell.html
9. • Lateral Line System
– Canals that run length of
body and open up to
surrounding H2O
– Used to detect movements in
water
• Locate prey and predators
– Ampullae of Lorezini
• Organs around head (what is
the term for sense organs near
the head?)
– Sense electrical
– http://dsc.discovery.com/vide
os/ultimate-guide-the-sharks-
vibrations-and-shark-
vision.html
10. Digestion
• Teeth
– Several rows of teeth
– Fall out and are continually
replaced throughout life
• Not like ours where we
only get two sets
– Shake head to bite b/c they
cant move jaws up and
down to chew
– Food is swallowed whole
– Mouth ->stomach-> small
intestine
11. Great White Jumping!!!
• http://dsc.discovery.com/videos/planet-earth-
pole-to-pole-great-white-hunt.html
12. Reproduction
• Sexual, separate sexes
• Fertilization is internal
– Males transfer sperm via
claspers
– Females have ovaries and
oviduct (modified uterus)
– http://dsc.discovery.com/vi
deos/ultimate-guide-the-
sharks-shark-mating.html
13. 3 types of Reproductive types
– Oviparity (most primitive)
• Eggs are laid outside body
• Develop in protective case that attaches to seafloor
• smaller b/c limited nutrients
• Whale sharks, bullhead sharks
– Ovoviviparity (most common)
• Eggs hatch in mothers uterus
• No placenta, nourishment is yolk stored in egg
• Single pup
– Viviparity (most recent, advanced)
• Babies get milk directly from mother
• Hammerhead shark
14. Skates and Rays characteristics
What animal from previous chapter do they resemble?
• Flattened bodies shape
– Suited for bottom living
• Always exception = manta
ray
– Enlarged pectoral fins
attached to head
– Reduced dorsal and caudal
fins
– Eyes and spiracles on top
of head
– Lack of anal fin
– Specialized teeth for
crushing prey
15. Differences between skates and rays
• Skates
– Small fins on tail
– Swim by creating a wave
and starts at head then
ripples down rest of body
– Oviparous - “mermaids
purse”
• Rays
– Venomous barb or
spines
– Swim by moving fins up
and down (like a bird)
– Ovoviviparous
