CHAPTER 14FISH, AMPHIBIANS, AND REPTILES
p. 394
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” p. 402
- simplest vertebrates.
- 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 Goblin Shark
Basking Shark Sawtooth Shark
More Cartilage Fish
Manta Ray
Skate
North Dakota Chondrichthyes
Paddlefish Sturgeon
3) Class Osteichthyes “bony fish”
- largest class of fish. (95%)
Three groups:
1) lung fish
- have simple lungs and gills.
ex. African lungfish
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?MantaClass Chondrichthyes
Northern
Class Osteichthyes
Lamprey
Class Agnatha
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.
- more advanced than fish.
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
- the change in form from egg to adult.
p. 412
egg
- have gills- must stay in water.
- develops legs.- tail is absorbed.- begins eating insects
- protein speeds up the process.
tadpole
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. 412Ex. 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
Zebra Lizard
Gecko
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’