Invertebrates

Octopus Video

Phylum ChordataC. Vertebrata

• Share four chordate characteristics + vertebral column (spine, backbone)

• Spine encloses and protects nerve cord (spinal cord)• Anterior end of spinal cord = brain protected by skull made of bone or

cartilage

1. Fishes• Oldest group of vertebrates (530 mya)

• 27,000+ species (15,600+ marine spp.)• Three major groups

Fishes

FishesA. Class Agnatha – Jawless fish

• No jaws• Unpaired fins and no scales1. Hagfishes

FishesA. Class Agnatha – Jawless fish

1. Hagfishes

FishesA. Class Agnatha – Jawless fish

2. Lampreys

FishesB. Class Chondrichthyes – Cartilaginous Fishes

• Includes sharks, rays, skates and ratfish• Cartilage skeleton• Movable jaws• Paired and Unpaired fins• Placoid scales

FishesB. Class Chondrichthyes – Cartilaginous Fishes

1. Sharks• Fusiform body• Heterocal caudal fin• Characteristic dorsal fin• Gill slits• Powerful jaws

FishesB. Class Chondrichthyes – Cartilaginous Fishes

1. Sharks• Wide size range

FishesB. Class Chondrichthyes – Cartilaginous Fishes

1. Sharks• Very good sensory organs

FishesB. Class Chondrichthyes – Cartilaginous Fishes

1. Sharks• Reproduction – live young or eggs

FishesB. Class Chondrichthyes – Cartilaginous Fishes

1. Sharks• Commercially hunted

FishesB. Class Chondrichthyes – Cartilaginous Fishes

2. Rays and Skates• Dorsally flattened bodies• Demersal• Ventral gills• Modified pectoral fins

a. Stingrays

FishesB. Class Chondrichthyes – Cartilaginous Fishes

2. Rays and Skates• Dorsally flattened bodies• Demersal• Ventral gills• Modified pectoral fins

a. Stingrays

FishesB. Class Chondrichthyes – Cartilaginous Fishes

2. Rays and Skatesb. Electric Rays

FishesB. Class Chondrichthyes – Cartilaginous Fishes

2. Rays and Skatesc. Manta Rays

FishesB. Class Chondrichthyes – Cartilaginous Fishes

2. Rays and Skatesd. Skates

FishesB. Class Chondrichthyes – Cartilaginous Fishes

3. Ratfishes

FishesB. Class Osteichthyes – Cartilaginous Fishes

• Skeleton of bone• Make up 96% of all fish• Cycloid and ctenoid scales• Operculum• Homoceral fin

FishesB. Class Osteichthyes – Cartilaginous Fishes

• Fin rays• Terminal mouth• Swim bladder

Fishes - BiologyA. Body Shapes

• Strongly related to lifestyle

Fishes - BiologyA. Body Shapes

1. Fusiform

Video

Fishes - BiologyA. Body Shapes

2. Laterally Compressed Video

Fishes - BiologyA. Body Shapes

3. Flattened

Fishes - BiologyA. Body Shapes

4. Eel-likeVideo

Fishes - BiologyA. Body Shapes

5. Unusual, Irregular

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