1. Phylum Chordata Have a notochord in embryo –Strong, rod-like structure that can bend Chordates include all of the vertebrates and two groups of invertebrates Types of Chordates: Invertebrates 1.Lancelets and tunicates Vertebrates 1.Fish 2.Amphibians 3.Birds 4.Reptiles 5.Mammals

2. Invertebrate Chordates http://evolution.berkeley.edu/ http://www.ramblincameras.com/ Tunicate Adult Tadpole-like Sessile Lancelet Tunicate Larva 3quarksdaily.com

3. Chordates: Fishes 4 groups of fish: –Lampreys –Hagfish –Cartilaginous fish (have flexible skeleton made of cartilage) – examples sharks, rays –Bony fish (skeletons contain bone) – salmon, trout Fish breath through gills –Absorb dissolved oxygen in water Fish are Ectotherms –Cold blooded –Blood temperature changes with surroundings Jawless, long & Snakelike, no scales

4. Fishes (continued) Swim bladder – gas filled sac, controls floating in fish Lateral line system – row of sensory organs that run on both sides of the body of fishes Operculum – protective flap that covers the gills of bony fishes