p. 394
CHAPTER 14
FISH, AMPHIBIANS, AND REPTILES
All are vertebrates and belong to the
Phylum Chordata
“chordates”
To be a chordate,
certain
characteristics must
be present at
sometime during its
life.
1) Notochord (p.395)
- a rod-like piece of cartilage
that runs along the dorsal side.
- it is present in
humans during
early development.
- it turns into the
backbone.
- some have a notochord their
entire life. (not vertebrates).
Example 1: tunicate
Example 2: lancelet
2) nerve chord
- turns into the
spinal cord.
- carries messages
from the brain.
3) gill slits
(pharanygeal
pouches)
- openings in the throat
area.
- found in all
vertebrates during the
embryo stage.
- turns into lungs.
All vertebrates have an endoskeleton.
Most vertebrates are ectotherms.
- “cold-blooded”
- their temperature
changes with the
environment.
Endotherms maintain a constant
temperature.
- “warm-blooded”
FISH
- 30,000 different
species.
- three classes.
1) Class Agnatha
“jawless
fish”
- simplest vertebrates.
p. 402
- no jaw - has a
‘sucker’ mouth.
- it sucks the fluids
out of its host.
-their skeletons are made of cartilage
- no real bones - very flexible.
Ex. Lampreys
- attack healthy
fish.
- live in the Great
Lakes (invasive
species).
Ex. Hagfish (p. 402)
- attacks dying or dead
fish.
2) Class Chondrichthyes (p. 402)
- are the
cartilaginous fish.
Ex. sharks, rays,
skates.
- have skeletons
made of cartilage.
They have traits of ‘advanced’ fish.
- scales
- sharp and pointy.
- not round.
- ‘hydrodynamic’
- jaws
- can ‘unhinge’.
Sharks
- most are not
dangerous but are
efficient predators.
- replaceable
teeth that slant
inwards.
- sense of smell
Largest =
Whale shark
(45 feet long)
‘Meanest’ =
Great White
- sharks can reproduce sexually in three
different ways.
1) young are born
‘live’.
2) lays eggs
3) eggs ‘hatch’ inside the
female.
More sharks…
Thresher Shark
Basking Shark
Goblin Shark
Sawtooth Shark
More Cartilage Fish
Manta Ray
Skate
North Dakota Chondrichthyes
Paddlefish
Sturgeon
3) Class Osteichthyes
- largest class of
fish. (95%)
Three groups:
1) lung fish
- have simple
lungs and gills.
ex. African
lungfish
“bony fish”
2) lobe-finned
- fins attach to
the skeleton.
Ex. coelacanth
3) ray-finned
- paired fins with
long bony spines.
- largest group.
Ex. walleye, perch,
salmon.
ASSIGNMENT:
WORKSHEET
‘FISH’
Features of a Bony Fish
lateral line
- runs along the side of the fish.
- can sense vibrations and electrical
currents.
gills
- water passes over the gills and they
extract oxygen.
- release CO2
- many tiny blood vessels.
operculum
- a bony plate which
covers the gills.
swim bladder
- controls buoyancy.
- fills with air to rise.
- no eyelids!
- two chambered
heart.
- reproduces
sexually.
- nostrils
- a strong sense
of smell.
- have a complete digestive system.
- stomach, liver, intestines…
WHICH CLASS OF FISH?
Manta
Class Chondrichthyes
Lamprey
Class Agnatha
Northern
Class Osteichthyes
READ “Origins of Fish” p. 406
ASSIGNMENT
WORKSHEET:
“GO FISH”
Class Amphibia “Amphibians” p. 407
Ex. frogs, toads
2,500 different
species.
Amphibians must live near water.
- keep skin moist.
- to reproduce
(lay eggs)
Many amphibians in Minnesota have
been found with deformities in recent
years.
- linked to the use
of pesticides.
- can easily be
absorbed thru
their skin.
Amphibians are ectothermic.
- during winter months they become
inactive
- slowed metabolism.
- called hibernation.
- some become inactive when
temperatures are too hot or when
water is scarce.
- bury themselves
underground.
- called estivation.
Amphibians need a strong
endoskeleton to support their body
while on land.
- they have a three chambered
heart.
Frogs
(p. 409)
- have lungs but can stay under for long
periods of time.
- can absorb oxygen through their skin.
- have hinged joints
- reproduce
sexually
- lay eggs in
water.
Hundreds of different species
and sizes
- colors are often
“bright”
-poisonous
Toads
- can spend more time
out of the water.
- skin is ‘bumpier’
- doesn’t dry out.
- but must return to
water to reproduce.
Salamanders
- often confused
with lizards.
- smooth skin
(no scales).
- amphib with a
tail.
Caecilians
- a legless, blind
amphibian
found in rain
forests
AMPHIBIAN METAMORPHOSIS
p. 412
- the change in form from egg to adult.
egg
tadpole
- have gills
- must stay in water.
- develops legs.
- tail is absorbed.
- begins eating insects
- protein speeds up the
process.
adult
Usually takes 4 - 6 weeks.
- warm water and
plenty of food will
increase the
speed of
metamorphosis.
- but can take
years…
ASSIGNMENT
WORKSHEET:
‘AMPHIBIANS’
Class Reptilia
‘Reptiles’ p. 412
Ex. turtle, snakes,
alligator.
- they do not have to
return to water.
1) scales
- keep moisture
in.
2) hard shell - amniotic egg
- more durable.
All* reptiles have claws.
Reptiles have a three chambered
heart.
- provides more oxygen to the
body.
- have lungs
- are land
organisms.
READ ‘Importance
and Origin of
Reptiles’ (p. 417).
Lizards
- most are small.
- but the Komodo Dragon can be 10 feet
long.
- most lizards are
harmless.
- many eat insects.
- some are
venomous.
More lizards…
Gila Monster
Fringed Lizard
Gecko
Zebra Lizard
Alligators
Snakes
- reptiles without
legs.
- can unhinge their
jaw.
- to swallow
large prey.
- some are venomous.
Rattlesnake
Coral Snake
Some reptiles have shown
maternal care.
- the mother
protects the eggs
and the young
after they hatch.
Reptiles are more advanced and
survivable than amphibians.
- water is the greatest limiting factor.
ASSIGNMENT:
WORKSHEET
‘ECTOTHERM REVIEW’