Life On Earth By Clarissa.renee_1212 3650 BCE Earliest evidence of life 2500 BCE first photosynthetic/autotrophic bacteria appear 2200 BCE first great extinction, oxygen producing bacteria "posion" the enviroment, age of aerobic organisms begins 1750 BCE first eukaryotes appear 650 BCE multicellular life appears 650 BCE sexual reproduction begins 550 BCE "Cambrian Explosion" huge diversity and complexity increase in a relatively short period of time 505 BCE marine invertebrates appear 438 BCE great extinction, fish appear 408 BCE land plants appear 360 BCE great extinction, amphibians appear 286 BCE reptiles appear 245 BCE great extinction, seed plants appear 208 BCE great extinction, mammals and dinosaurs appear 144 BCE primitive birds appear 66 BCE great extinction, dinosaurs disappear 60 BCE primates appear 38 BCE anthropoids appear (day-- active primates) 37 BCE primitive horses appear 2 BCE historical date of jesus birth 1 BCE humans appear 2 USA's declaration of independence