Transcript The Fish - Rochester CUSD 3A

The Fish
Classification
The term “Fish” refers to three different
vertebrate classes:
 Agnatha—jawless fish
 Chrondrichthyes—cartilaginous fish
 Osteichthyes—bony fish
The Fish
Adaptations that enable fish to be
successful in the water:
 stream-lined shape
 muscular tail—move rapidly
 paired fins—move r and l, up or down,
backward or forward
The Fish
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unpaired fins on the back and belly—
increase stability
mucus secretion—reduces friction when
swimming
The Fish
Fish body position:
The tissue in a fish’s body are denser than
water and by controlling the amount of
gas in their bodies helps to regulate
vertical position (swim bladders)
They store lipids, which are less dense
than water, to help them float.
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Homeostasis
Homeostasis—stable internal conditions of
a living thing
Bodies of freshwater fish have a higher
concentration of solutes than the
surrounding water so the fish tend to
gain H2O through osmosis and lose ions,
such as Na+ and Cl- through diffusion
Homeostasis
Saltwater fish contain lower
concentrations of solutes than their
surroundings so the fish tend to lose
water and gain ions.
Kidneys and gills play an important role in
maintaining homeostasis in the tissues
and ridding the body of metabolic wastes
Homeostasis
Some fish may move from fresh to salt
water by adjusting kidney functions
Respiration
The presence of scales limit gas exchange
through the skin, so fish rely on membranes
of the gills for oxygen and carbon dioxide to
diffuse
Gills are located on either side of the pharynx
and are composed of feathery, threadlike
structures called filaments
Respiration
Each filament has a network of fine capillaries
that provides a large surface area for the
exchange of CO2 and O2.
Fish pull O2 rich water in through their mouths,
pumping it over their gill filaments and
pushing the O2 poor water out through
openings in the sides of the pharynx
Respiration
Lamprey and shark have several gill
openings, but most have a single gill
opening on each side of their bodies.
The opening is hidden beneath a protective
bony cover called the operculum.
Respiration
Lungfish have an adaptation that allows
them to survive in O2 poor water or in
areas where bodies of H2O dry up
They have specialized organs that serve as
lungs and a tube brings O2 from the air
to this organ in their mouth
Respiration
Some lungfish are so dependent on O2 from
the air that they will suffocate if they
don’t reach the surface
Other lungfish can actually burrow into
mud, cover itself with mucus and lay
dormant for months until rain falls.
Feeding
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Fish can be herbivores, carnivores,
parasites, filter feeders, or detritus
feeders (organic matter). A single fish
may exhibit several modes of feeding,
depending on what is available.
EX: Carp eat algae, aquatic plants,
worms, mollusks, arthropods, dead fish
and organic matter.
Feeding
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EX: Barracudas are highly specialized
carnivores
EX: Some lampreys are parasitic.
Digestion
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From the mouth, food passes through
the esophagus to the stomach where it is
partially broken down.
The pyloric ceca, in many fish, are
finger-like pouches that further digest
food. It secretes digestive enzymes and
absorbs nutrients.
Digestion
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The liver and the pancreas add enzymes
and other digestive chemicals to the
food as it moves through the digestive
tract.
Intestines complete the process of
digestion and absorption of nutrients.
Digestion
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Undigested material is eliminated
through the anus.
Excretion
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Nitrogenous wastes are eliminated in the
form of ammonia by diffusion through
the gills into the water, or removed by
the kidneys, which filter wastes from
the blood
Kidneys also help control the amount of
H2O in their bodies.
Response
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Fish have well developed nervous systems,
organized around a brain.
The most anterior parts are the olfactory
bulbs, which are involved with the sense of
smell, which is the primary sense in the fish.
They are connected to two lobes of the
cerebrum. The cerebrum is responsible for all
voluntary activities of the body.
Response
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Optic lobes process info from the eyes.
The cerebellum coordinates body
movement.
The medulla oblongata controls the
functioning of many internal organs.
Response
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Most fish have highly developed sense
organs.
Almost all fish that are active in daylight
have well developed eyes with color vision
that is as good as ours.
Chemoreceptors are responsible for
sense of taste and smell.
Response
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Most fish have ears inside their head,
they may not hear sounds well, but they
can detect gentle currents and
vibrations with a sensitive receptor
called the lateral line system. It is a
row of sensory structures that run the
length of the body on each side and are
connected (by nerves) to the brain
Response
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Catfish and shark can detect low levels
of electric current.
The electric eel can generates its own
electricity.
Circulation
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Fish have a closed circulatory system
The heart pumps blood around the body
in a single loop
-heart to the gills to rest of the body
and back to the heart
Circulation
The heart consists of four parts (only two
chambers)
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sinus venosus—thin walled sac that collects
blood from the fish’s veins before it flows to
the atrium
atrium—large muscular chamber that serves
as a one-way compartment for blood that is
about enter the ventricle
Circulation
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ventricle—thick walled, muscular chamber,
the pumping portion
bulbus arteriosus—large, muscular tube,
connects to a large blood vessel called the
aorta
Movement
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Fish move by alternately contracting
paired sets of muscles on either side of
the backbone, this creates a series of sshaped curves that move down the fish’s
body. As the curve travels down the
body of the fish it creates a backward
force on the surrounding water. This
force, along with the action of the fins,
propels the fish forward.
Movement
Fins are used to stay on course and adjust
direction and provide an extra boost of
speed. A swim bladder is used to adjust
buoyancy and is located beneath the
backbone and is an internal gas-filled
organ.
Reproduction
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Eggs are fertilized either internally or
externally depending on the species.
In many species, females lay the eggs
and the embryos in the eggs hatch
outside the mother’s body (oviparous).
Embryos obtain food from the yolk in the
egg. EX: Salmon
Reproduction
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In other species, eggs stay in the
mother’s body after internal
fertilization, each embryo develops
inside its own egg, using the yolk for
nourishment. The young are born alive
(ovoviviparous). EX: guppies
Reproduction
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A few species of fish, including several
sharks are viviparous, the embryos stay
inside the mother’s body, but they
receive nourishment directly from the
mother’s body and are also born alive.
Fish Classification
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Class Agnatha
80 species
hagfish and lampreys
jawless fish, skin has neither plates nor
scales
have an eel-like body and a cartilaginous
skeleton with unpaired fins
notochord remains throughout life
Fish Classification
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Class Chondrichthyes
have skeletons composed of cartilage (a
flexible, lightweight material made of cells
surrounded by tough fibers of protein)
have moveable jaws
have paired fins
approx. 800 species of sharks, skates and rays
live in salt water
Fish Classification
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all species are carnivores (some are
scavengers)
that eat many different kinds of food,
including fish, seals, aquatic invertebrates and
plankton.
are covered with placoid scales—small, toothlike spines that feel like sandpaper. These
scales reduce turbulence in the water and
increase swimming efficiency.
Classification
Sharks
 Largest sharks, the whale shark, up to 59 ft in
length and the basking shark up to 49 ft in
length. They eat plankton.
 They have large, curved tails, torpedo-shaped
bodies and pointed snouts. Sharks swim in a
side to side pattern created by the motion of
their asymmetrical tail fin.
Classification
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Paired pectoral fins are located behind
the head and jut out like the wings of a
plane.
Their mouth has 6 to 20 rows of teeth
that point inward. When a tooth in a
front row breaks or wears down, a
replacement moves forward to take its
place. They may have more than 2000
teeth over a lifetime.
Classification
Rays and Skates
 have flattened bodies
 paired wing-like pectoral fins
 some species have whip-like tails
 rays have diamond or disk-shaped bodies,
skates have a triangular body
Classification
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3.3 ft long or less
bottom dwellers
flat shape and coloration are used as
camouflage on the ocean floor
feed on mollusks and crustaceans
Bony Fishes-ClassOsteichthyes
Period of Fish is known as the Devonian
Period.
 Fish were the first vertebrates to evolve
and early fish were jawless and covered
with bony plates.
 Bony Fish are characterized by three
features:
Bony Fish
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Skeleton made of bone
Lungs or swim bladder
*only a few fish have lungs today (are
called the lung fish)
*most have swim bladders (a gas-filled sac
that is used to control buoyancy). Swim
bladders are thought to have evolved from the
lungs of early bony fishes.
Bony Fish
Scales-most bony fish are covered with
scales
 protect the fish
 reduce water resistance
Bony Fish
Biologists have divided the bony fish into
two main groups:
 lobe-finned fish
 ray-finned fish
Bony Fish
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Lobe-finned fish-have fleshy fins that are
supported by a series of bones, lobes are bony
and rigid. Only 7 species exist today. (six
species of lungfish and one species of
coelacanth)
Lungfish exchange gases through the lungs and
gills and live in shallow tropical ponds that
periodically dry up, they burrow into the mud
and cover themselves with mucus to stay moist
until the pond refills.
Bony Fish
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These fish are important because
extinct lobe-finned fish are thought to
be ancestors of amphibians and all other
terrestrial vertebrates
Bony Fish
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Ray-finned fish-have fins that are
supported by long, segmented, flexible
bony elements called rays, which are
bony yet flexible. Rays probably evolved
from scales. These fish are very diverse
in appearance, behavior and habitat. (EX.
eels, yellow perch, trout, salmon, guppies,
bass, herring and darters)
Bony Fish
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Countercurrent flow-in gills of fish, an
arrangement where water flows away
from the head, and blood flows toward
the head, if blood and water flowed in
the same direction, less O2 would be
diffused