timeline of earth By vanessagaray 541 BCE cambrian explotion 470 BCE first land plants 230 BCE diosaurs 5 BCE proliferation of cyanobacteria 4 BCE first fossil evidence 3 BCE earliest evidence of life 2 BCE evolution of prokaryotic cells 2 BCE evolution of eukaryotic cells 1 BCE formation of earth crust and ocean 7 evolution of multicellular organisms