4560 Ma Earth and planets form 4510 Ma Moon forms 4470 Ma Oldest lunar rocks 4000 Ma Oldest continental rocks 3800 Ma Evidence of erosion by water 2700 Ma Start of rise of atmospheric oxygen 3500 Ma Record of magnetic field Fossils of primitive bacteria 2500 Ma Major phase of continent formation completed 542 Ma Evolutionary Big Bang 443 Ma Mass extinction 420 Ma Earliest land animals 125 Ma Earliest flowering plants 5 Ma First hominids 0.2 Ma First appearance of our species, Homo sapiens Mass extinctions 359 Ma251 Ma 200 Ma 65 Ma Present 1500 1000 2000 3000 4000 500 A Brief Journey Through Geologic Time…