Cartilaginous Fish marine bio final

3 types and their difference

Sharks, rays, and skates

Skeleton material

Cartilage

Mouth placement

Usually ventral (underside)

Shape of tail

Heterocercal tail with a larger upper lobe

Shape of scales

Placoid scales (dermal denticles)

Stiff dorsal/pectoral fin

Provide lift and stability

Gill slits

5–7 exposed gill slits and no operculum

Which features help with buoyancy?

Large oily liver

Which features help with speed?

Heterocercal tail

Which features help with both?

Pectoral fins

What's special about their teeth?

Continuously replaced throughout life

Nictitating membrane

Protective eyelid

How do they breathe?

Water passes over the gills and some species must keep swimming

How do they reproduce?

Internal fertilization using claspers

Ampullae of Lorenzini

Electroreceptors that detect electric fields

Evolutionary age of sharks

About 400 million years old

How sensitive is a shark's sense of smell?

Extremely sensitive and can detect tiny amounts of chemicals

Where do sharks live?

All oceans from shallow reefs to the deep sea

Whale shark

Largest fish and a filter feeder

Basking shark

Second-largest fish and a filter feeder

Tiger shark

Large predator known for a varied die