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Vertebrates: Part I. Fishes & Amphibians. Phylum Chordata. Chordates: includes all the vertebrates Have 3 common characteristics: Nerve Cord: hollow tube that hold nervous tissue
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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 Chordata • The 5 Groups: • Fish: cold blooded • Amphibians: cold blooded • Birds: warm blooded • Reptiles: cold blooded • Mammals: warm blooded
Fishes • Live in freshwater or saltwater • Bone or cartilage protects brain & spinal cord • Gills for respiration • Mostly 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 Fishes • Jawless Fish • Lamprey, Hagfish • Cartilaginous Fish • Sharks, rays, and Skates • Bony Fish • Most common fish
Jawless Fish • Have no bone, only cartilage • Flexible • Use teeth and their tongue to eat
Cartilaginous Fish • No bones, only cartilage • Toothlike scales • Sharks can have 1000’s of teeth in up to 20 rows
Cartilaginous Fish • Skates 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 Fish • Swim in Schools • Swim Bladders: gas filled sac that gives fish buoyancy
Amphibians (Amphi- double) • Cold Blooded • Most have metamorphosis • Breathe with gills when immature and lungs and skin when they are adult • Use both internal and external fertilization
WHY THEY LIVE ON LAND AND WATER • Drying out: skin needs to be moist to breathe • Respiration: use gills as a baby • Reproduction: 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
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.