Presentation on theme: "CHAPTER 14 FISH, AMPHIBIANS, AND REPTILES p. 394."— Presentation transcript:
CHAPTER 14 FISH, 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 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.