Old people had strong teeth for eating tough plants and seeds without damaging their enamel
Old people had strong teeth for eating tough plants, seeds and nuts without damaging their enamel, study claims
- Scientists thought that tough plants and seeds were avoided by old people
- But new analysis reveals that the tough plant tissue has no harmful effect
- Only minor damage is done and not enough to justify avoiding a food source
- It is now thought that hard plant foods may have formed a larger part of the diet of early human ancestors than is currently assumed
Scientists have long been convinced that prehistoric people avoided eating tough plants because they damaged their teeth.
It is now thought that hard plant foods may have formed a larger part of the diet of early human ancestors than previously thought.
Scientists in the US discovered that even the most difficult plant tissues barely wear primate teeth.
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Pictured: a schematic drawing of seeds that are mechanically protected by woody woody tissue. (a) Large seeds of some dicotyledonous plants are protected by a woody seed shell (b) Even small seeds of monocotyledons have timbered pericars that protect the seeds inside, making it difficult to break open
“We discovered that hard plant tissues such as the shells of nuts and seeds hardly affect the texture of micro clothing on teeth,” said Adam van Casteren, professor of biological anthropology at Washington University in St. Louis.
Scientists studied bornean orangutan choosing to see how hard plants affected enamel.
They discovered that microscopic wells were not made by hard plant tissue, such as nuts and seeds, as expected.
“If teeth don’t show extensive pits and scars, this doesn’t necessarily exclude the consumption of hard-food items,” said Dr. van Casteren.
The study highlighted a little known group of old people known as austrolopiths who had large, powerful jaws.
It is suspected that they also had extremely powerful jaw muscles, comparable to some modern primates.
“All of these morphological characteristics seem to indicate that they had the capacity to produce large bite forces and were therefore likely to be chopped on a diet of hard or bulky food products such as nuts, seeds or underground sources such as tubers,” said Dr. van Casteren.
Researchers attached small pieces of seed trays to a probe and repeatedly dragged them over the enamel of a bornean orangutan molar tooth. The seed fragments did not make large pits, scratches or breaks in the glaze, the researchers found – only shallow grooves (photo)
Researchers attached small pieces of seed trays to a probe and dragged them repeatedly over the enamel of a Bornean moland.
A total of 16 different tests were performed to replicate three types of nuts that form modern primates diets, each with different hardness.
Researchers also dragged the seeds with the same amount of force as a jaw would cause.
The seed fragments did not make large pits, scratches or breaks in the enamel, the researchers found.
There were a few shallow grooves, but the scientists saw nothing to indicate that hard plant tissues could make an important contribution to dental micro clothing.
However, the seed fragments themselves showed signs of degradation because they were rubbed against the enamel.
Researchers now believe that large australopithic jaws could be used to chew large amounts of seeds and that it would not damage the teeth.
“And that makes perfect sense in terms of the shape of their teeth,” said Peter Lucas, co-author of the Smithsonian Tropical Research Institute, “because the blunt, low-cut shape of their molars is ideal for that.”
“Consuming many very small hard seeds probably requires large biting forces to grind all grains,” said Dr. van Casteren.
“In the light of our new findings, it is likely that small, hard objects such as grass seeds or sedge nuts were a food for early hominids.”
WHEN DO PEOPLE HAVE FIRST FIRST?
The timeline of human evolution can be traced back millions of years. Experts estimate that the family tree as such goes:
55 million years ago – First primitive primates evolve
15 million years ago – Hominidae (great apes) evolve from the ancestors of the gibbon
7 million years ago – First gorillas evolve. Later chimp and human lines diverge
A recreation of a Neanderthal is shown
5.5 million years ago – Ardipithecus, sharing early ‘proto-human’ traits with chimpanzees and gorillas
4 million years ago – Monkey like early people, the Australopithecines appeared. They had brains no larger than those of a chimpanzee, but other, more human traits
3.9-2.9 million years ago – Australoipithecus afarensis lived in Africa.
2.7 million years ago – Paranthropus, lived in forests and had huge jaws to chew
2.6 million years ago – Hand axes become the first major technological innovation
2.3 million years ago – Homo habilis first thought to have appeared in Africa
1.85 million years ago – First ‘modern’ hand appears
1.8 million years ago – Homo ergaster begins to appear in fossils
800,000 years ago – Early people control fire and create fireplaces. The brain size is increasing rapidly
400,000 years agoO – Neanderthals appear for the first time and spread across Europe and Asia
300,000 to 200,000 years ago – Homo sapiens – modern people – appear in Africa
50,000 to 40,000 years ago – Modern people reach Europe