Vertebrates: Part I
Fishes & Amphibians
Phylum Chordata Chordates: includes all the vertebrates Have 3 common characteristics:
– Nerve Cord: hollow tube that hold nervous tissue
– Notochord: rod that runs down the back for support (in higher vertebrates it is replaced with the vertebral column)
– Throat with gill slits: used for breathing (in higher vertebrates these turn into the trachea)
Phylum Chordata There are 5 groups in the phylum
Chordata we will study– 3 groups are cold blooded: no internal
temp regulation. They take on the temp of their surroundings
– 2 groups are warmblooded: maintain a constant body temp
Phylum ChordataThe 5 Groups:
–Fish: cold blooded
–Amphibians: cold blooded
–Birds: warm blooded
–Reptiles: cold blooded
–Mammals: warm blooded
FishesLive in freshwater or
saltwaterBone or cartilage protects
brain & spinal cordGills for respirationMostly external fertilization
Fishes 3 Characteristics:
– Scales
– Fins
– Throat with gill slits Closed Circulatory System Well developed nervous system Keen sense of smell and taste
Classes of FishesJawless Fish
–Lamprey, HagfishCartilaginous Fish
–Sharks, rays, and SkatesBony Fish
–Most common fish
Jawless FishHave no bone,
only cartilageFlexibleUse teeth and
their tongue to eat
Cartilaginous FishNo bones, only
cartilageToothlike scalesSharks can
have 1000’s of teeth in up to 20 rows
Cartilaginous FishSkates and
Rays use poison or electric volts to stun their prey
Bony Fish
Have bony skeleton
Most common type of fish
Many different species
Have paired fins
Bony FishSwim in SchoolsSwim Bladders:
gas filled sac that gives fish buoyancy
Fish Structure
Amphibians (Amphi- double)Cold BloodedMost have metamorphosisBreathe with gills when
immature and lungs and skin when they are adult
Use both internal and external fertilization
WHY THEY LIVE ON LAND AND WATERDrying out: skin needs to be
moist to breatheRespiration: use gills as a
babyReproduction: eggs don’t
have hard shell
AMPHIBIANS
2 Groups–frogs, toads
–salamanders, newts
FROGS AND TOADS Hibernate during winter Skin:
– Frogs: smooth and moist– Toads: warty and dry
Large hind legs for jumping: helps them to escape predators
Lay their eggs in water
Frog Life Cycle
SALAMANDER & NEWTS
VERY SIMILIAR TO FROGS EXCEPT:– No large back legs: cant jump– Do not hibernate
Lay their eggs in water
SALAMANDERS & NEWTS
Clawless Have short smooth moist bodies Long tail. They do not have scales.