Transcript SENSATIONALLY SHOCKING SHARKS Part 1

NOTE: STUDENTS WRITE EVERYTHING!!
SENSATIONALLY
SHOCKING
SHARKS Part 1
* Ichthyologist – one who
studies fish and sharks
I. General Information
A. Definition: large,
predatory,
cartilaginous fish
(NO BONES)
B. Unlike other ‘fish’
bec. of cartilaginous
skeleton instead of
bones
C. Species today are
still similar to those
100 million years
ago
D. Found in all
oceans, but esp.
tropical and
subtropical waters;
many even migrate
up rivers!
http://sharks-ocearch.verite.com/
http://dsc.discovery.com/tv-shows/shark-week/videos/top-10-weird-sharks.htm
E. Over 375 species;
less than 10%
considered
dangerous
I’m a vegetarian,
really I am!!! Hee hee
hee!
streamlining: The Sharks- The vast
Variety of Shark Species (2:59)
F. People are
bitten each
year, but
you’re more
likely to be
injured in a
car than
swimming at
the beach!
Look out for
the what??
Streamlining:
What Are the Odds?
Shark Attack (2:24)
II. Physical Characteristics
A. Coloration:
1. most are gray,
blue, or brown
2. most are counter
shaded
(counter=oppose)
- light shades on
bottom, darker
shades on top
Wait, this is
my good side!
Streamlining: World’s Best series:
Living dinosaurs- sharks (3:32)
B. Size
1. Whale shark – largest;
49 feet; 40,000 pounds
Are you
my
mother?
Streamlining: Assignment black sea
of cortez- whale shark (2:29)
2. Pygmy ribbon tail
catshark- one of
the smallest; 9 in.
C. Skin
1. Leathery skin
with small,
sharp pointed
scales called
denticles
(dent = tooth)
2. denticles- smaller versions
of the teeth; smooth, overlapping scales from cranial
(head) to caudal (tail) areas,
but very rough from caudal
to cranial that rubbing some
species could cause injury
7-gill shark
Spiny dogfish shark
Nurse shark
D. Respiration (breathing)
1. 5-7 gill slits behind
the head
2. How Gills Function:
a. shark closes gills and opens
mouth to let water in
b. shark closes mouth to force
water out through the gill
slits
c. Blood vessels inside the gills
absorb oxygen from the
passing water
E. Teeth
1. Enlarged versions
of the denticles
2. Multiple, conveyor
belt-like rows
Streamlining: the Sharks- the jaws
of the beast: how a shark’s teeth
work (1:19)
3. Constantly being replaced
since they only last 8 to 10
days
4. Usually lost in flesh of prey
5. May use 20,000 teeth in a
lifetime
Streamlining: The ultimate guide:
Sharks- shark teeth: varied in
design & purpose (1:40)
6. Two basic types
a. triangular for shearing
and cutting
b. Spiky for
spearing and
holding prey
F. Tails
1. Variety of sizes and
shapes
Thresher shark
2. Aid in movement and
balance
3. Aid in attacking prey
4. Used in defense
against predators
G. Floatation
1. Don’t have swim
bladders like bony fish
do, therefore they sink
to the bottom when
motionless
Streamlining: the ultimate guide:
sharks- common chars. Of sharks
2.
Cartilaginous skeleton helps
them float (lighter than bones)
3. Large liver (up to 25%
of the shark’s weight),
filled with oil, that is less
dense than water, which
also helps them float
Whale shark
III. Senses

Streamlining: The
ultimate guide:
sharks- the evolution
of sharks (2:31)
A. Hearing
1. Best
of senses
2. Some can hear prey in
the water from 3,000
feet away (over ½
mile!)
B. Smell
1. Second
best sense
2. 2/3 of the shark’s brain
is devoted to smell
3. Some can smell 1
molecule of blood in a
million molecules of
water!
4. Nostrils
used for
smell only
C. Sight
1. Less
acute, but used
when approaching prey
2. Very sensitive to light
3.
Some sharks have 3
eyelids; an upper, a
lower, and one that
covers the entire eye
4. Nictitating membrane: protects
the eye; closes when the shark
passes close to objects and also
during biting or feeding.
Nictitating membrane
Streamlining: Exploring Sharks'
Sense of Vision and Hearing (1:38)
http://dsc.discovery.com/tv-shows/shark-week/videos/mythbusters-vs-sharks.htm
D. Other
1. Ampullae of
Lorenzini- small spots
on the nose that
detect faint electrical
impulses produced by
other animals.
Ampullae of Lorenzini
(1 continued) An animal in
distress (trouble) sends
many more impulses than
one swimming in a
rhythmic pattern.
Streamlining:Studying the Role of
Electromagnetic Signals in
Predation of Great White Sharks
(05:17)
2. Lateral line- a fluidfilled canal beneath the
skin along the sides of
the shark. It detects
tiny vibrations made by
swimming prey through
pores that indicate
position of the prey.
End of Part 1! 