Figure 1 family tree for Hominoidea (apes and humans) showing how the classification is linked to what is known about evolutionary relationships. For example, the chimpanzee, Australopithecus and Homo lines diverged from the gorilla line about 6.5-7 million years ago, which is reflected in their grouping in the tribe Hominini. Dates of splits between groups are known only approximately. For example, the earliest known fossil of a hominoid (ape) is dated at 26 million years old, so the date for the origin of Hominoidea is placed at 30 million years