Human Evolution

A new analysis of early human teeth from extinct fossils has found that they expanded their diets about 3.5 million years ago to include grasses and possibly animals. Before this, humanlike creatures - or hominins - ate a forest-based diet similar to modern gorillas and chimps. Researchers analysed fossilised tooth enamel of 11 species of hominins and other primates found in East Africa. The findings appear in four papers published in PNAS journal. Like chimpanzees today, many of our early human ancestors lived in forests and ate a diet of leaves and fruits from trees, shrubs and herbs. But scientists have now found that this changed 3.5 million years ago in the species Australopithecus afarensis and Kenyanthropus platyops. Their diet included grasses, sedges, and possibly animals that ate such plants. They also tended to live in the open savannahs of Africa.

The new studies show that they not only lived there, but began to consume progressively more foods from the savannahs. Researchers looked at samples from 175 hominins of 11 species, ranging from 1.4 to 4.1 million years old. Their diet was analyzed from the chemical make up of their teeth, identifying the carbon isotopes within them. The ratios of different types of carbon atoms, or isotopes, in fossils can give clues to what a fossil creature ate because different foods have different carbon isotope signatures. "Because feeding is the most important factor determining an organism's physiology, behaviour and its interaction with the environment, these finds will give us new insight into the evolutionary mechanisms that shaped our evolution," said Dr Zeresenay Alemseged, from the California Academy of Sciences.

 

Exploring new environments and testing new foods, ultimately might be correlated with further changes in human history.


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