Fishes Phylum Chordata

Review: Chordates 500 mya Evolved from invertebrate chordates Chordates Begin!!!

Post-anal Tail Cat Human

Vertebrates Vertebrates differ from chordates because of BACKBONE Backbone = vertebral column or spine Made of vertebrae Encloses & protects nerve cord

Fishes

Fish vs. Fishes Fish – single individual OR more than 1 individual of the same species Fishes –more than one species

Fish Oldest & Most Primitive Vertebrates 30,000 species; half the living vertebrates on earth $$$ Important to Economy

Classification

Class Agnatha Jawless Fishes Most primitive Feed by suction Have round muscular mouth Body: Long, Lack fins, Lack scales Types: Hagfish - Detritivores Lamprey - Parasitic

Fresh Bait Left in Ocean 6 Hours Later Fresh Bait Left in Ocean

Class Chondrichthyes

Class Condrichthyes Cartilaginous fish Advanced Features: Types Sharks Movable jaws Ventral mouth Paired Lateral Fins Types Sharks Fast swimmers Sharp teeth, rows Skate and Rays Flattened bodies Spine on tail Ratfish Deep water Flap of skin to protect gills

Class Condrichthyes - Sharks

Hammerhead Sharks

Sawshark

Thresher shark

Spiny Pygmy Shark

Whale Shark

Class Condrichthyes – Rays and Skates

Manta Ray

Class Condrichthyes – Ratfish

Class Osteichthyes

Class Osteichthyes Bony Fish Skeleton at least partially bone 21,500 species = 98 % of all fish About 50% of all vertebrates 2 Classes: Actinopterygii - Ray-finned fish Sarcopterygii - Lobe finned fish

Lobe-finned Ray-finned

Osteichthyes Adaptations Mouth Mouth is almost always terminal Teeth not in rows Swim Bladder - Gas filled sac that regulates buoyancy Skin Thin flexible scales Scales covered in layer of tissue Tissue covered with mucus Operculum – gill cover

External Anatomy

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