Beyond the iconic cartoon: Human evolution was never a straight line

For much of modern history, human evolution was imagined as a straight line. One species replaced another in neat sequence, culminating in modern humans. The iconic ‘ape to man’ cartoon showing a stooped primate gradually standing upright captured that idea for generations.

That picture began shifting in the second half of the 19th century as scientists started unearthing human-like fossils. The discoveries revealed a more complex, branching story instead of a single line.

At the time, researchers dated fossils using geological clues. They looked at the depth of the find and the rock layers surrounding it to decide which fossil was older or younger. The method established relative age but could not provide precise dates.

The new fossil record, combined with later dating techniques, has since replaced the linear model with one showing multiple hominin species coexisting and branching out over time.