Evolutionary Path from Fish to Humans N Cambrian Ordovician PreЄ T J K PgPg O SD P Є C N Vertebrate Precursors 1 st Vertebrates ~ 425 mya Jawed Vertebrates~ 460 mya Ray & Lobe FinBony Fish > 420 mya Tetrapodomorpha ~ 409 mya Reptiles ~ 312 mya Mammals ~ 225 mya

Evolutionary Path from Fish to Humans N Vertebrate Precursors 1 st Vertebrates 125 mya

Geologic Time Periods Color Coded Cambrian Ordovician Haydean Archean Proterozoic Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleocene Neogene Quaternary Haydean 4567 – 3600 mya Archean 3600 – 2500 mya Proterozoic 2500 – 541 mya Cambrian 541 – 485 mya Ordovician 485 – 443 mya Silurian 443 – 419 mya Devonian 419 – 359 mya Carboniferous 359 – 298 mya Permian 298 – 252 mya Triassic 252 – 201 mya Jurassic Cretaceous Paleocene Neogene 23 – 2.6 Quaternary present Haydean 4567 – 3600 mya Archean 3600 – 2500 mya Proterozoic 2500 – 541 mya Cambrian 541 – 485 mya Ordovician 485 – 443 mya Silurian 443 – 419 mya Devonian 419 – 359 mya Carboniferous 359 – 298 mya Permian 298 – 252 mya Triassic 252 – 201 mya Jurassic Cretaceous Paleocene Neogene 23 – 2.6 Quaternary present

Haeckel's Paleontological Tree of Vertebrates (circA 1879) Ca m br ia n Ordovician The evolutionary history of species has been described as a "tree", with many branches arising from a single trunk. While Haeckel's tree is somewhat outdated, it illustrates clearly the principles that more complex modern reconstructions can obscure.