Animals-Vertebrates Notes

Animals-Vertebrates Notes - Animals Vertebrates Phylum...

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Animals – Vertebrates Phylum Chordata Characteristics: 1) notochord: a stiff, flexible rod ; provides skeletal support-more Cartilage than Bone - extends length of body; supports body 2) dorsal nerve chord - a neural tube; brain at anterior end ; hollow nerve cord 3) gill slits : evolved so an animal could take in and expel water easily; later oxygen uptake 4) post-anal tail Vertebrates: chordates with a backbone Phylum Chordata has three “sub-phyla” - “urochordata” - “cephalochordata” - “vertebrata” – with seven classes ; animals with a true backbone The Seven Classes…. 1) Class Agnatha: jawless fishes - eel-like - cartilaginous skeleton - some parasitic ; latch onto other organisms -toothed oral disc 2) Class Chondrichthyes: cartilaginous fish - 350 million years old - have jaws… - sharks, skates, rays… ancient ancestors to bony fish - * entirely cartilaginous – no bone -no swim bladder; STOP moving and they sink Development of Jaws 3) Class Osteichthyes: Bony Fish ; ray finned fishes
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Animals-Vertebrates Notes - Animals Vertebrates Phylum...

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