Change in early human ancestor diet came earlier than thought

Change in early human ancestor diet came earlier than thought
Credit: University of California Museum of Paleontology

(—A team of researchers in the U.S. has found that our early human ancestors expanded their diet to include savannah grasses and other food sources approximately a quarter of a million years earlier than had been previously thought. In their paper published in Proceedings of the National Academy of Sciences, the team explains how they tested a variety of fossilized teeth, what they found and the impact the change in diet likely had on the ability of our ancestors to thrive.

Scientists have known for quite some time that the of our changed, from eating mostly leaves and berries, to grasses, tubers and eventually meat. But the timing of that changeover has been up for speculation, though many have believed it was approximately three and a half million years ago. To pin down the time frame, the researches with this new effort gained access to 152 fossilized teeth found in sites in Africa, from a variety of primates and other ancient animals and carbon tested them to collect evidence of the types of food that the creatures that used them ate.

In looking at the results, the team found that most of the primates had been eating C3 type plants (so named because they have three-carbon atoms) which generally meant and berries and some cool weather grasses. In contrast, they found that some species of primates (our early ancestors) had added C4 type plants to their diet as far back as 3.76 million years ago, which included savannah grasses, tubers and sedges. This is an important point in human history, the team notes, because adding such foods to the diet allowed our to broaden their range because they could survive under more variable conditions—not only were more foods available to them, but the new kinds of food offered more energy. And that, the researchers suggest, set them apart, and led eventually to mass migrations and even greater adaptations.

Scientists report earlier date of shift in human ancestors' diet
A field worker shows a fragment of a hominin tooth from Woranso-Mille, Afar, Ethiopia, one of 152 tooth fragments sampled for isotope analysis to find evidence of diet change. Credit: Yohannes Haile-Selassie, Cleveland Museum of Natural History

The researchers note that the changes in diet only came about after changes in teeth and jaws evolved in a way that allowed for chewing the new types of food—and of course, changes in the digestive tract to allow for gaining nutrients and energy from them.

Explore further

Researchers find human ancestors switched to eating grasses earlier than thought

More information: Dietary change among hominins and cercopithecids in Ethiopia during the early Pliocene, Naomi E. Levin, PNAS, DOI: 10.1073/pnas.1424982112

The incorporation of C4 resources into hominin diet signifies increased dietary breadth within hominins and divergence from the dietary patterns of other great apes. Morphological evidence indicates that hominin diet became increasingly diverse by 4.2 million years ago but may not have included large proportions of C4 foods until 800 thousand years later, given the available isotopic evidence. Here we use carbon isotope data from early to mid Pliocene hominin and cercopithecid fossils from Woranso-Mille (central Afar, Ethiopia) to constrain the timing of this dietary change and its ecological context. We show that both hominins and some papionins expanded their diets to include C4 resources as early as 3.76 Ma. Among hominins, this dietary expansion postdates the major dentognathic morphological changes that distinguish Australopithecus from Ardipithecus, but it occurs amid a continuum of adaptations to diets of tougher, harder foods and to committed terrestrial bipedality. In contrast, carbon isotope data from cercopithecids indicate that C4-dominated diets of the earliest members of the Theropithecus oswaldi lineage preceded the dental specialization for grazing but occurred after they were fully terrestrial. The combined data indicate that the inclusion of C4 foods in hominin diet occurred as part of broader ecological changes in African primate communities.

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Citation: Change in early human ancestor diet came earlier than thought (2015, September 15) retrieved 21 July 2019 from
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Sep 15, 2015
Any date beyond 5,000 - 10,000 years is honestly an act of speculation. The dating techniques are simply not that accurate, and are fitted to a timeline chronology. Those which do not fit are thrown away. All dates require that there have been no significant changes to the Earth over these timespans, like through some large-scale interaction with other bodies in space, because those events would necessarily scramble these dates. Further, numerous dramatic assumptions are required to lend the impression that the dates are reliable. Willard Libby was the first to encounter this problem, and he went to enormous lengths to deal with it. If you look at the samples he used to make his case, you will notice that the radiocarbon data changes in his favor from one published paper to the next, with no explanation of a correction. It appears he falsified the data, yet nobody seems to notice or care.

Sep 15, 2015
Honestly, what is it with this science aggregate site that attracts creationist anti-science nutjobs? The rest of us appreciate the science for what it is and for the amazing progress it does. The above is an excellent example!

@plasmarevenge: It is easily seen from hundreds of thousands of accepted papers by dating specialists you are full of it - as expected from a troll.

For one glaring example, you erroneously claim that all datings are "fitted to a chronology". It is the reverse, to avoid unnecessary errors most datings are isochron absolute datings which is easily done on mineral samples say. (Just pick different grains.) [ https://en.wikipe...n_dating ]

Carbon dating is only valid and used on samples less than 50 kyrs.

But you know all this, and that you are lying your face off for you magic beliefs. I write this for those who may never seen a creationist troll in full lying mode before.

Sep 15, 2015
When I clicked on this story from facebook it tried to also show me two creationist troll website links under this link. If that tells you how many of them there are clicking on any story about evolution, so they can immediately come attempt to shit on it and claim it's proof of god. If there is a god, he would want you to understand how his creation works, not arrogantly assume some nearly cave-man level monks wrote down all god had to say on the matter of everything thousands of years ago.

Sep 15, 2015
Plasmasrevenge is a sockpuppet of hannesalfven, not known necessarily for being a creationist troll but just a troll in general.

Sep 15, 2015
Honestly, what is it with this science aggregate site that attracts creationist anti-science nutjobs?
1- the lack of moderation
2- it is accessible with anonymizers
3- Trolls be trolls

Sep 20, 2015
C3 plants have 3 carbon atoms. Is that all? They must be very small.

Sep 21, 2015
Honestly, what is it with this science aggregate site that attracts creationist anti-science nutjobs? The rest of us appreciate the science for what it is and for the amazing progress it does. The above is an excellent example!

It doesn't attract any more; they spew whenever they get the chance. But other sites delete the cut/paste/spam trolling and PO takes money from conservative organizations to not delete the nut-jobs, as most extend their wisdumb to AGW. What do you expect from a site that a) moves offshore and stops filing yearly statements with Companies House, b) uses Adblade/Taboola/Outbrain spam, and c) has 10-20 tracking cookies active each time you visit? PO was a great idea from two physics students. It has since been sold to pimps, so we're up to our neck in intellectual sluts, johns and low lives.

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