Download Class: Chondrichthyes - Sharks and Rays The shark`s skeleton is

Class: Chondrichthyes - Sharks and Rays
The shark’s skeleton
is entirely composed
of cartilage.
The skin is covered
with tiny scales
called denticles.
They are similar in structure to teeth and cause the skin to be very
abrasive if rubbed in the wrong direction.
Most have gray, brown, white or black coloring; are not
camouflaged but may be counter-shaded.
Only predators are toothed whales and man. Puffer fish can
accidentally suffocate a shark by blocking water from entering
the gills resulting in death for both.
1
2
Predation: Efficient, top carnivore of the sick, weak, old and injured.
Jaw is lined with rows of teeth like a
conveyor belt (modified scales).
Teeth can be replaced every 24 hours
and are used to identify species.
Jaw can be extended out of the mouth
for extra reach.
3
Circulation: 2 chambered heart; cold-blooded
Respiration: Gills are located in muscular slits (gill slits, no
operculum) behind the mouth.
They exchange oxygen from the water into the blood.
Sharks lack swim bladders (have oily livers) and must
constantly swim upwards to balance their weight.
They do sleep.
4
SHARK BODY SHAPE - fusiform
SHARK FINS Pectoral – Fixed
Caudal Fin – longer upper lobe
5
Senses: Vision is good in
clear water. Eyelids close
from the bottom upwards to
prevent injury during an
attack.
Smell is excellent. Olfactory lobes compose 2/3 of the brain. Sharks
can detect a drop of blood 1/4 mile away in the water and can
determine the direction of the source.
Hearing is excellent. Sound vibrations can be detected by the
lateral line from 3,000 feet away.
The electrical impulses of breathing from a prey can be picked
up through pores in the face (ampullae of Lorenzini).
6
Reproduction: sexual, internal fertilization. Most sharks have live
births - dogfish have 4-10 pups, tiger sharks may have 80-100 at
one time. A few species lay eggs.
7
Shark attacks on humans are rare, but
with more people in the water the odds
are increased.
Sharks may be looking
for new food sources due
to over fishing.
Most attacks occur in less than 6 feet of water, at dawn or dusk,
during summer months. Risks are also increased for surfers and
swimmers in water with reduced visibility.
A surfer in black wet-suit, paddling out on a board, may look
enough like a seal to interest a shark.
8
Most attacks occur in Florida,
California, Australia, and
Africa. Florida has 4 times
the number reported in
California. Most attacks are not
fatal.
Sharks only kill less than 2
people worldwide per year.
548 fatalities since 1580
Bees kill hundreds of people and
crocodile/alligator - related
deaths number nearly 1000.
People have done far
greater damage to the
shark population.
9
10
The whale shark is over
50 feet long. It is a filterfeeder with baleen instead
of teeth.
Largest shark
Great White sharks are
found in the temperate
and tropical oceans
worldwide.
Most dangerous
Track Mary Lee
11
FINNING
12
Largest ray
Manta Rays may
have a 25 foot
wide wing span.
Most dangerous
Sting Rays have a venomous
stinger in their tail. Shuffle
your feet when wading to
avoid stepping on it.
13