Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ancestors skip adolescence

06.12.2001


Dental diary of a teenage hominid aged 1.5 million years.


Teeth tell the tale of early hominid lives.
© SPL


Homo erectus: an earlier evolutionary pattern.
© SPL



Our early ancestors never went through the awkward age, suggests a new analysis of dental records. Extended youth may have emerged relatively late in human evolution.

Although apes cut the apron strings at around 12 years, despairing human parents are well aware that their kids take at least 18 years to grow up. The development of this prolonged growth period is seen as a key event in human evolution, allowing extra time for learning.


Homo erectus, our 1.5-million-year-old ancestor, was previously assumed to have developed like us. In fact, it grew up more like an ape, Christopher Dean of University College London and his colleagues have found1. H. erectus was fully grown at 14-16 years, Dean estimates.

The creatures shortened their growth by dodging adolescence, says anthropologist Barry Bogin of the University of Michigan in Dearborn. The terrible teens evolved later to allow us to learn about parenthood, he suggests. Homo sapiens need practice because "we deal with social complexities that Homo erectus didn’t have".

But Dean argues that the phase in modern human growth missing from Homo erectus’ history cannot be pinned down to adolescence based on current evidence.

Dental history

Dean’s team charted our ancestors’ growth spurts using teeth. Our wisdom teeth emerge at 18, but apes’ erupt at 11. On a finer scale, tiny daily oscillations in the activity of cells that secrete enamel are recorded as microscopic lines in the tooth’s crown. "You can see every day in the life of a human," Dean explains. Thinner increments show that modern humans have a slower rate of growth.

By totting up periodic ridges on the outside of teeth, the team calculated dental-formation times in fossilized skeletons of the youth of yesteryear: from H. erectus to Neanderthals, who lived 300,000 years ago, to apes. Homo erectus gained their first molars at around 4 to 4.5 years, the team estimate, closer to apes at 3.5 years than to humans at age 6.

The slightly longer childhood matches Homo erectus’ slightly bigger brain, says Jacopo Moggi-Cecchi, who studies human evolution at the University of Florence in Italy. In addition to cultural development, humans’ protracted growth allows extra time for brain development, he argues.

The fact that Homo erectus carried itself like a human led to the assumption that it grew up like one, explains Moggi-Cecchi - yet its brain size and dentition suggest it fits an earlier evolutionary pattern.

References
  1. Dean, C. et al. Growth processes in teeth distinguish modern humans from Homo erectus and earlier hominins. Nature, 414, 628 - 631, (2001).


HELEN PEARSON | © Nature News Service
Further information:
http://www.nature.com/nsu/011206/011206-10.html

More articles from Interdisciplinary Research:

nachricht Fighting myocardial infarction with nanoparticle tandems
04.12.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Virtual Reality for Bacteria
01.12.2017 | Institute of Science and Technology Austria

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>