Three skulls (IMAGE)
Caption
The researchers report that hominin teeth, especially molars, became smaller and longer over millennia to accommodate a growing diet of tough grass-like plants known as graminoids and their underground storage organs. They found that the turn toward grasses began about 3.8 million years ago with the distant human relative Australopithecus afarensis (left). About 2.3 million years ago, the early human Homo rudolfensis (center) gained regular access to carbohydrate-rich underground plant organs such as tubers, bulbs, and corms. But this dietary shift toward outpaced tooth evolution until about 2 million years ago when species such as Homo ergaster (right) exhibited a spurt of change in tooth size and shape better suited to eating and breaking down cooked plant tissues to derive their nutrients.
Credit
L to R: Public domain; Don Hitchcock; Fernando Losada Rodríguez (rotated)
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License
Public Domain