Transcript Fish - TeacherWeb

Fish
Gill breathing, ectothermic, aquatic
vertebrate that has fins, skin covered
in scales.
Classes of fish
Myxini – Hagfishes
 Cephalaspidomorphi- Lampreys
 Chondrichthyes- Cartilaginous fish
(sharks-rays)
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2 classes of bony fish
Actinopterygii – ray finned fishes – 23,000
species
 Sarcopterygii – lobe finned fishes(fleshy) –
8 species (coelacanth)
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Modes or reproduction
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Oviparous – egg layed
OvoviviparousDeveloping young
stay in oviduct and are
nourished by yolk sac
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Viviparous- true live
bearing – nourished by
placenta
Myxini
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Hagfish
Scavengers
43 species
Almost blind
Keen sense of smell
Hooks onto prey two
toothed plates
Myxini
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Eel like body
Slime glands(milky
white)
No fins
Caudal fin along
dorsal surface
Cartilaginous
Smooth skin(naked)
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No stomach
No cerebellum
Fluids same as
seawater
No larval stage
Possess both sex
organs only one
functional
Cephalaspidomorphi
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Lamprey mouth
Holds rocks to anchor
Parasitic and
predaceous
Cephalaspidomorphi
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Sexes separate
Single gonad
Sucker mouth
Well developed teeth
17 species found in
North America
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Also found Eurasia
Breed in freshwater
Anadromos – swim up
river
Cephalaspidomorphi
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Lampreys attached
Eel like
Naked skin
Regulated body fluids
No stomach
Well developed eyes
Chondrichthyes
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Sharks
Rays
Skates
850 living species
Chondrichthyes
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Rays
Specialized for life on
the sea floor
Skates
Electric rays
Sting rays
Bat rays
Chondrichthyes
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Rays
Gill openings on
underside of head
Spiracles on top
Water taken in
through the spiracles
Chondrichthyes
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Many sharks don’t
survive in captivity or
they act very different
in aquariums
So many species of
sharks are still not
well researched
Chondrichthyes
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Pelvic fins in male
modified to form
claspers
Fusiform
body(spindle)
Two olfactory sacs
Endoskeleton entirely
made up of cartilage
Five to seven sets of
gills
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No swim bladder or
lung
Keen sense of smell
Lateral line
Electroreception
Moderate vision
Chondrichthyes
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Separate sexes
Internal fertilization
Oviparous
Ovoviviparous
viviparous
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25 freshwater
2nd largest vertebrates
Heterocercal tail-turns
up
Sarcopterygii- fleshy finned
Actinopterygii
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Bony fish
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rockfish
Osteichthyes - Actinopterygii
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Perch
Osteichthyes- Actinopterygii
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Clownfish
Osteichthyes
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Seahorse
Osteichthyes
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Seahorse
Osteichthyes
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Piranha
Osteichthyes
Osteichthyes
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410 million yrs ago
Most numerous and
diverse group of
vertebrates
Diverse body form
Specialized jaws
Capable of osmotic
regulation
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Separate sexes
External fertilization
Respiratory Functions
(Exchange of Gases)
Mouth-Take in oxygen(water) and food
 Operculum-(Protects gills)-Opens and
closes to help oxygen move over the gillsincreases efficiency
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Water enters mouth travels to
pharynx(throat)and passes over gills
 The outward motion of the Operculum
creates a negative pressure increasing
volume of water over gills
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Early fish
The first fishes had a lack of paired fins and
no jaws
 Decreased mobility and sources of food
 Development of jaws expanded food
sources available
 Carnivores /herbivores etc.
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Locomotion Functions
(Movement to Keep Upright)
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Pectoral Fins and
Pelvic Fins-Used for
steering, slow
swimming and to keep
the fish upright
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Dorsal and Anal FinUsed for stability
Caudal Fin-Used for
movement and fast
swimming
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Pectoral fin – front
legs
Pelvic fin – hind legs
Protective Functions
Skin Pigment-Provides camouflage
 Scales-Protects the skin, parasites, easier
swimming
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Sensory Functions
(Transfer Stimuli to Nerve
Impulses)
Nostrils-Lets chemicals into the nostril
cavity (smell, olfactory bulbs)
 Eyes-Large pupils let more light in to help
seeing
 Lateral Line-Connection of nerve endings
that carry low frequency vibrations and
depth pressure. Depth and solid objects.
 Tongue-touch, oxygen movement, food
movement
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Anadromous- lives at sea return to fresh to
spawn - salmon
 Catadromous- lives in fresh water return to
sea to spawn- eels
 Homing instinct regulated by smell of
parent stream
 Position of sun gets them to the river mouth
 From ocean
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Internal Anatomy
Respiratory-gases between blood and oxygen
Gill-Oxygen passes over the gills, O2 is
absorbed through the membranes of the
Filaments by diffusion.
Countercurrent blood flow
Blood circulation is opposite water flow
 Allows for maximum efficiency of oxygen
absorption
 85%
 Some fish need to keep moving
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Circulatory Functions-O2, Nutrients, Remove wastes
Heart-2 chambered-Pumps only
deoxygenated blood
 Spleen-Removes old blood cells
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Deoxygenated blood goes through heart to gills
then to body of fish to deliver oxygen
Closed system – separate oxygenated and
deoxygenated blood
 Single pump/single loop
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Locomotion
Air/Swim Bladder-Adjusts float level by
changing density of gases
 Ears-helps to maintain balance and
equilibrium
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Weberian ossicles are small bones that
transmit sound vibrations from swim
bladder to the inner ear.
 Hearing of faint sounds improved
 catfish
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Digestive Functions-Absorption of Food
into the Blood
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Teeth-used to bite and
hold food
Esophagus-used to
carry food to the
stomach
Intestine-digestion of
food and absorption of
the food
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Stomach-digestion and
storing of food
Pyloric Caeca-secretes
digestive enzymes
Liver-makes bile to
aid in digestion
Gall Bladder-digests
fats
Excretory Functions-Removal of
Metabolic wastes from body
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Kidney and gills-removes nitrogen from
blood
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Solid wastes removed through anus