Time before Present,Time to Next Event,Event
"3700000000","2400000000",Life
"1300000000","750000000","Eucaryotic cells, multicellular organisms"
"550000000","220000000",Cambrian Explosion (body plans)
"330000000","135000000",Reptiles
"195000000","113500000",Class Mammalia
"81500000","49000000",Primates
"32500000","25500000",Superfamily Hominoidea
"7000000","3100000",Family Hominidae
"3900000","2100000",Human ancestors walk upright
"1800000","800000","Genus Homo, Homo Erectus, specialized stone tools"
"1000000","700000",Spoken language
"300000","200000",Homo sapiens
"100000","75000",Homo sapiens sapiens
"25000","15000","Art, early cities"
"10000","5000",Agriculture
"5000","2490","Writing, wheel"
"2510","1960",City States
"550","325","Printing, experimental method"
"225","95",Industrial Revolution
"130","65","Telephone, electricity, radio"
"65","38",Computer
"27","14",Personal Computer