Est . 4 Billion Years Ago
THE EARLIEST LIFE FORMS ON EARTH WERE MICROSCOPIC
ORGANISMS THAT EVOLVED IN THE WATERS OF THE FIRST OCEANS .
Est . 5.5 Million Years Ago
THE FIRST PRIMATES EVOLVED IN THE FORM OF THE RODENT-LIKE CLIMBERS CARPOLESTES AND DRYOMOMYS , EVOLVING FEATURES THAT SET THE FOUNDATIONS OF THE APPEARANCE OF MODERN PRIMATES , INCLUDING FINGERNAILS AND TOENAILS .
EARLY PRIMATES ( Image : Mat Severson , Northern Illinois University )
AUSTRALOPITHS
Est . 3.2 Million Years Ago
THE EARLIEST UNDISPUTED MEMBERS OF THE HUMAN FAMILY WERE THE AUSTRALOPITHS ,
AS THEY WERE ABLE TO STAND ON TWO LEGS . THEIR BRAINS WERE ABOUT THE SIZE
OF MODERN CHIMPANZEES ’, AND BASED ON THE DISCOVERY OF “ LUCY ”, A FAMOUS
AUSTRALOPITH FOSSIL OF THE SPECIES AUSTRALOPITHECUS AFARENSIS , THEY WOULD
HAVE GROWN TO SIZES SIMILAR TO CHIMPS .
HOMO ERECTUS ( Image : Christian Jegou / Public Photo Diffusion / SPL )