Transcript document

Chapter 3
Section 2
Fish

Largest group of vertebrates

Fish:
Ectothermic vertebrate
 Lives in water
 Has fins to use for movement
 Obtain oxygen through gills
 Have scales to cover the skin

Obtaining Oxygen

How and where do
fish get their oxygen?
The water contains
oxygen
 Water moves through
the fishes throat to the
gills
 Gills have blood
vessels in them

Obtaining Oxygen

Water flows over the gills

Oxygen moves from the water into the blood

Carbon dioxide moves out of the blood and into
the water

The water leaves by flowing out the slits beneath
the gills
Circulatory System

From the gills:

Blood travels
throughout the
body in vessels

Blood travels to all
regions of the body

Oxygen is supplied
to the cells
Circulatory System

What type of
circulatory system
do they have?


Closed
The heart pumps
the blood ->
Moving and Feeding

How do fish move?

Using a fin

A fin is a thin
membrane stretched
over a bony support

Provides a large
surface to push against
the water
Moving and Feeding

What are the bodies of fish adapted to do?


Efficient feeding
Barracuda
Sharp and pointed teeth
 Why would they want sharp
teeth?

Moving and Feeding

What type of teeth do trout
have?


Short and blunt teeth
What type of teeth do
basking sharks have?

Comb-like structures to filter
tiny animals
Nervous system and Senses

Why would fish want to have a highly
developed nervous system and senses?
Find food
 Avoid predators
 Touch, taste, smell, and sight help them
capture their food
 A shark can smell and taste one drop of blood
in 115 liters of water

Reproduction

How do they reproduce?
Externally
 Male hovers close to the
female
 Releases a cloud of sperm
over the released eggs


Sharks and guppies have
internal fertilization
Groups of Fish

What are the three groups of fish?
Jawless
1.
2.
Cartilaginous
3.
How are they classified?
Structure of their mouth and type of skeleton


Bony
Jawless Fish

Jawless fish
information
Earliest
vertebrates
 60 species today
 Modern jawless
fishes have no
scales
 Skeletons made of
cartilage

Do not have a pair
of fins

Do not have jaws
– can’t bite

Lamprey
Jawless fish

How do they eat without a jaw?


Have structures for scraping, stabbing, and
sucking
What are the only kinds of jawless fish?

Hagfish and lamprey
Hagfish
Jawless Fish

Hagfish
Large, slimy looking worms
 Crawl into the bodies of dead or dying fish
 Use their sandpaper tongue to consume
decaying tissue


Lamprey
Parasites to other fish
 Attach to healthy fishes and suck in the
tissues and blood of their victims

Cartilaginous Fishes

What are their skeletons made of?


Cartilage like jawless fish
What makes them different from jawless
fish then?
Have jaws
 Have a pair of fins

Cartilaginous Fishes

Information on cartilaginous fishes

Pointed, tooth-like scales
 Have
a texture rougher than sandpaper

All are carnivores
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Rays and skates live on the ocean floor

Sharks, rays, and skates are all types
White Shark
Barndoor Skate
Blue-Spotted Ray
Shark’s Body

How would you describe a shark?
Stream lined body
 Mouth on the bottom of its head
 Jagged teeth arranged in rows

 Use
only the 1st row of teeth
On the Move

How do sharks get oxygen?


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Rely on currents to get water across their gills
Position themselves in currents to get water over their
gills at night
What do sharks spend most of their time doing?


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Hunting
Attack and eat nearly anything that smells like food
Have bad eye sight
Sleeping Shark
Bony Fishes

What are types of bony fish?
Trout
 Tuna
 Goldfish
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What is different about bony fish?

Have a pocket over their gills
Bony Fish
Swim Bladder

How do fish swim at different depths?

Swim bladder:
 Gas-filled
sac that allows them to stabilize their
body at different depths
 Filled
with oxygen, nitrogen, and carbon dioxide
 Volume
of gas can become larger or smaller
 Change
in volume changes the buoyant force
Swim Bladder
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Buoyant Force:

Force that water exerts upward on an
underwater object
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If the buoyant force is greater than the weight
of the object it floats

If the buoyant force is less than the weight of
the object it sinks
Diversity of Bony Fish
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Make up 95 % of all species of fish
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Live in salt and fresh water
Sea Dragon
Flying Gurnards
Clownfish
Balloon fish
Bluefin Tuna
Trout