Transcript fish - tayloekrhs

What is fish with out an eye.
FSH
History
• Earliest fish had no jaws
and no paired fins-filtered
feed
• 1st fish bodies covered with
bony plates
• For 100 million years-fish
were the only vertebrates
Superclass Agnatha
• Jawless vertebrates
• Most primitive, living
vertebrates
• Ostracoderms (extinct);
lamprey and hagfish
• Lack paired
appendages;
cartilaginous skeleton;
notochord throughout
life; rasping mouth
Superclass Gnathostomata, I
• Placoderms (extinct): first with hinged jaws and paired appendages
• Class: Chondrichthyes~ Sharks, skates, rays
• Cartilaginous fishes; well developed jaws and paired fins; continual water
flow over gills (gas exchange); lateral line system (water pressure changes)
Rise of Sharks & Bony Fish
• About 400 mya all the other fish
disappeared and were replaced by sharks
and bony fish.
• The jaws improved-developed the
hyomandibular arch from gills
• More fins developed.
•
Continue
Sharks became the top predators-
skeletons of cartilage
• Sharks first fish with bony teeth
• Sharks use internal fertilization and
pups born alive
• Skates and ray develop around 200
mya
Life cycles:
Oviparous- eggs hatch outside
mother’s body
Ovoviviparous- retain fertilized eggs;
nourished by egg yolk; young born live
Viviparous- young develop within
uterus; nourished by placenta
Bony Fish
• Evolved 400 mya
• Developed heavy bony skeleton for protection
and anchoring of muscles
• Evolved in fresh water
• Developed two types
– Ray finned most fish perch- has swim bladder95% of all fish are teleosts (advanced ray finned fish)
– Lobe finned evolved 390 mya-fin is more like limb
than fin-EX :Coelacanth
• Some lobed-finned fish walk on land
Key Adaptations
• 1. Gills for breathing
• 2. Backbone
• 3. Single looped circulation system- blood is
pump from heart to gills to body back to heart
• Nutritional requirements fish are unable to
make all the amino acids needed so they must
get these amino acids by eating them- (true for
all vertebrates)
Superclass Gnathostomata, II
• Class: Osteichthyes
• Ossified (bony) endoskeleton; scales operculum(gill covering); swim
bladder (buoyancy)
• Most numerous vertebrate
• Ray-fined (fins supported by long, flexible rays): bass, trout, perch,
tuna, herring
• Lobe-finned (fins supported by body skeleton extensions): coelocanth
• Lungfishes (gills and lungs): Australian lungfish (aestivation)
Bony Fish adaptations
• Swim bladder secrets and absorbs gases in order to make fish
rise or sink in water-gas is CO2
• Lateral line system sensory organ located along the side of a fish
(hearing)
• Gill cover (operculum) hard plate covering the gills that pumps to
push water over gills (so fish doesn’t have to swim to breath.)
Homework
• Draw a picture of a fish and label each findetermine what each fin does.