Class Chondrichthyes aka Cartilaginous fishes sharks and rays sharks and rays.
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Transcript of Class Chondrichthyes aka Cartilaginous fishes sharks and rays sharks and rays.
Class ChondrichthyesClass Chondrichthyes
aka Cartilaginous fishesaka Cartilaginous fishes
sharks and rayssharks and rays
General CharacteristicsGeneral Characteristics
These organisms have a skeleton made of These organisms have a skeleton made of cartilagecartilageThese organisms have movable jaws with lots of These organisms have movable jaws with lots of teeth teeth Mouth is almost always located under the headMouth is almost always located under the head
These organisms have paired lateral finsThese organisms have paired lateral finsSkin is covered in placoid scalesSkin is covered in placoid scales Sand paper like material that are made of the same Sand paper like material that are made of the same
material as the teethmaterial as the teeth
Placoid Scales
SharksSharks
Adapted for fast swimming and some are the top Adapted for fast swimming and some are the top predators in the seapredators in the seaVery few have evolved from their original formsVery few have evolved from their original formsThey have a well developed caudal finThey have a well developed caudal finTypically have paired dorsal and pectoral finsTypically have paired dorsal and pectoral finsThey have 5 to 7 gill slits on each side of the They have 5 to 7 gill slits on each side of the bodybodyOften have rows of powerful teeth and Often have rows of powerful teeth and constantly replace teeth as they lose themconstantly replace teeth as they lose them
Sharks cont.Sharks cont.
Found mostly in tropical waters at almost all Found mostly in tropical waters at almost all depthsdepthsFished for their meat, oil and skin which is used Fished for their meat, oil and skin which is used like leatherlike leatherShark fins are used in the Orient for medicinal Shark fins are used in the Orient for medicinal soupssoupsOver fishing of sharks has damaged the Over fishing of sharks has damaged the populations so restrictions are beginning to populations so restrictions are beginning to apply apply
Sharks cont.Sharks cont.
Hammerhead SharkHammerhead Shark Flattened headsFlattened heads Eyes and nostrils at Eyes and nostrils at
the tips of the flat headthe tips of the flat head Head is used as a Head is used as a
rudderrudder Space between eyes Space between eyes
and nostrils improves and nostrils improves sensory abilitiessensory abilities
Sharks cont.Sharks cont.
Whale SharkWhale Shark Largest fishLargest fish Found in tropical Found in tropical
waterswaters Can be 60 ft longCan be 60 ft long All are filter feedersAll are filter feeders
Rays and SkatesRays and Skates
Almost all have flattened bodies and are Almost all have flattened bodies and are bottom dwellersbottom dwellers
The most identifiable characteristic are the The most identifiable characteristic are the ventrally located gill slitsventrally located gill slits
The pectoral fins are greatly expanded The pectoral fins are greatly expanded and resemble wingsand resemble wings
StingrayStingray
Most common type of ray off Most common type of ray off our beachesour beachesHave a whip like tail with a Have a whip like tail with a barb at the basebarb at the baseThe barb has a poison gland The barb has a poison gland Often cover themselves with Often cover themselves with sandsandFeed on clams, crabs and Feed on clams, crabs and other small fishesother small fishesTeeth are modified into Teeth are modified into grinding plates to crush their grinding plates to crush their preyprey
Electric RayElectric Ray
Have specialized cells Have specialized cells on each side of the on each side of the body that produce body that produce electricityelectricity
Stun fish to eatStun fish to eat
Ancient peoples used Ancient peoples used to use the shock to to use the shock to cure illnessescure illnesses
Rat FishRat Fish
Have only one Have only one pair of gill slitspair of gill slits
Some have a Some have a long rat-like taillong rat-like tail
Feed on Feed on crustaceans crustaceans and mollusksand mollusks