Fig Dorsal, hollow nerve cord Anus Muscular, post-anal tail Pharyngeal slits or clefts Notochord Mouth Muscle segments

Fig Dorsal, hollow nerve cord Notochord Tail Cirri Mouth Pharyngeal slits Digestive tract Atrium Atriopore Segmental muscles Anus 2 cm

Fig Tunic Water flow Excurrent siphon Atrium An adult tunicate Pharynx with slits Anus Atrium Excurrent siphon Incurrent siphon to mouth Dorsal, hollow nerve cord Incurrent siphon Excurrent siphon Muscle segments Notochord Tail Stomach Intestine Esophagus Stomach Pharynx with slits A tunicate larva

Fig Lobed fins Legs Amniotic egg Milk Jaws, mineralized skeleton Lungs or lung derivatives Vertebral column Head Notochord Common ancestor of chordates ANCESTRAL DEUTERO- STOME Echinodermata (sister group to chordates) Chondrichthyes (sharks, rays, chimaeras) Cephalochordata (lancelets) Urochordata (tunicates) Myxini (hagfishes) Petromyzontida (lampreys) Mammalia (mammals) Actinopterygii (ray-finned fishes) Actinistia (coelacanths) Amphibia (frogs, salamanders) Dipnoi (lungfishes) Reptilia (turtles, snakes, crocodiles, birds) Chordates Craniates Vertebrates Gnathostomes Lobe-fins Osteichthyans Tetrapods Amniotes

Fig (a) Yellowfin tuna (Thunnus albacares) (b) Clownfish (Amphiprion ocellaris) (c) Sea horse (Hippocampus ramulos us) (d) Fine-spotted moray eel (Gymnothorax dovii)

Fig (a) Order Urodela (b) Order Anura (c) Order Apoda

Fig (a) Tuatara (Sphenodon punctatus) (c) Wagler’s pit viper (Tropidolaemus wagleri) (b) Australian thorny devil lizard (Moloch horridus) (e) American alligator ( Alligator mississippiensis) (d) Eastern box turtle (Terrapene carolina carolina)

Fig (a) Emu (b) Mallards (c) Laysan albatrosses (d) Barn swallows

Fig b

Fig (e) Bonobos (a) Gibbon (d) Chimpanzees (b) Orangutan (c) Gorilla