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.