Sharks!

Shark & Ray Classification

Domain: Eukarya Kingdom: Animalia▪Phlym: Chordata▪Subphylum: VertebrataClass: Chondroichthyes—sharks rays and all relatives Subclass: Holocephali—ChimarerasSubclass: Elasmobranchii—Sharks and Rays

Basic Characteristics of Cartilaginous Fish

Class Chondrichthyes Includes sharks,

rays, skates, and sawfish

Jawed fish

Lack a swim bladder

Skeletons made of cartilage (not bone)

Energy Savers

Though sharks are constantly swimming, they actually manage to do so without using much energy at all.

How do they do it? Cartilage is lighter than bone Large, oily livers keep them buoyant

Their energy saving techniques make them successful hunters—they do not have to eat as much, leaving them more energy to strike prey, and allows them to be quick and inconspicuous

Getting Lift

The shape of a shark’s fin and a ray’s body act like wings and give them lift

It allows them to glide through the water easier

Scaly Skin

Scales called denticles cover the body

They are very similar to shark teeth

Point towards the tail and reduces friction from water

Toothy Grin

“Conveyor belt” teeth that swing into place when old teeth are lost or need to be replaced

Sharky Sense

Heightened sense of smellLateral Lines—detect water motion

and vibrationsAmpullae of Lorenzini detect

electrical currents generated by muscles of animals (electroreception)

Baby Sharks Eggs are fertilized

internally using the male’s claspers to transfer sperm from male to female sharks.

The claspers are paired copulatory organs found at the base of the pelvic fins.

Fertilized eggs are produced and… Some are released into the water Others hatch in the mother’s

body and they give live birth

3 ways sharks give birth Oviparous—Species that lay

eggs that mature and hatch outside of the body like birds

Viviparous—Give birth to live young

Ovoviviparous—Sharks have eggs that hatch and develop within the mother’s body (so she give produces eggs, but give birth to live young.

**Intrauterine Cannibalism** Some baby sharks eat all of their brother and sisters in the womb so that only 1 baby shark is born.

Conservation Concerns

Sharks are animals that mature later and produce fewer offspring

Therefore populations are easily affected by hunting

Hunters of the Hunters The family Lamnidae =

most dangerous predators of all of the chrondroichthyes Include mako sharks and

great white sharks

Incite fear into humans and are therefore killed without limit—making humans the most dangerous predators in the ocean.

Truth Behind the Attacks

On average there are fewer than 10 fatal shark attacks a year

However, tens of thousands of sharks are killed each year

Sharks don’t kill any more than bees, mountain lions, and tigers

But if they do…

How to Survive

Mega Sharks

Whale shark (46 feet) Basking shark (33 feet) Megamouth shark (20 feet) AND ALL ARE FILTER FEEDERS!

Super Rays

Manta Ray (26 feet) FILTER FEEDER AS WELL!