Philippa Kaur

Early humans evolved a faster fetal growth rate than other apes about a million years ago, suggesting it could have played a role in the evolution of our species

Humans

3 October 2022

By Carissa Wong
A series of hominid craniums (clockwise from the left): juvenile Australopithecus, juvenile chimpanzee, adult chimpanzee, adult Australopithecus, adult Homo erectusTesla Monson
High prenatal growth rates found in modern people may have first evolved in ancient hominids less than a million years ago, according to estimates based on fossil teeth.
Human fetuses grow by around 11.6 grams per day on average – considerably faster than the fetuses of gorillas, the next fastest ape in the hominid family, with a rate of 8.2 grams per day.
“We found that human-like gestation [may have] preceded the evolution of the [modern human] species – around 200,000 to 300,000 years ago – and may in fact be a critical factor that led to our evolution, particularly our large brains,” says Tesla Monson at Western Washington University.Advertisement
Previously, researchers studying the evolution of human gestation have relied on fossilised pelvises and the rare remains of infants.
Monson and her colleagues found that across primates, prenatal growth rates are closely correlated with the ratio of the lengths of the first and third molar teeth.
The researchers built a mathematical model that could predict prenatal growth rates from the size of molars from 608 primates, including apes and African and Asian monkeys.
They then used the model to predict the prenatal growth rates of 13 hominid species from their fossil molar teeth. This revealed that hominid prenatal growth rates increased after our lineage split from chimpanzees around 5 to 6 million years ago, becoming more similar to those of modern humans than other apes around 1 million years ago.

Monson is unsure why prenatal growth rate and the molar length ratio may be related, but she and her team are investigating whether certain genes might control both. She acknowledges that extrapolating prenatal growth from skeletal remains may not be reliable. “Since we don’t have a time machine, we can’t directly compare our reconstructions with real values in the past,” she says.
However, the estimated rise in prenatal growth rates over this period coincides with increases in pelvis size and brain size among hominids. “It’s really cool that our reconstructions align with so many other lines of evidence,” says Monson.
“The authors’ primary finding that human-like prenatal growth rates emerged less than 1 million years ago, in concert with major increases in brain size, is convincing,” says Anna Warrener at the University of Colorado Denver.
“Teeth are frequently found in the fossil record and would be a fantastic tool for such evaluations in the future,” she says.
“The study is of great importance. It is incredibly difficult to access information about fetal growth rates from skeletal remains due to poor preservation. The authors have opened up new ways of overcoming this obstacle,” says Patrick Mahoney at the University of Kent, UK.
Journal reference: PNAS, DOI: 10.1073/pnas.2200689119
Sign up to Our Human Story, a free monthly newsletter on the revolution in archaeology and human evolution

More on these topics: More

Archaeologists once viewed ancient Nubia as separate from and inferior to Egypt. But research is now showing the Nubians had their own rich culture that powerfully influenced the land of the pharaohs

Humans

3 October 2022

By Colin Barras
The pyramids of Meroë in Sudan were built by Nubian pharaohsChristopher Michel
THE middle of the 19th century was the heyday of Egyptology. Hieroglyphs had been deciphered and people could finally grasp the full richness of the ancient Egyptian civilisation. The pyramids, the mummies, the statues – it all came to life. But some European Egyptologists felt the best was yet to come. As they worked their way further south, they believed they would find older relics, perhaps even the cradle of the Egyptian culture.
In this atmosphere, Prussian archaeologist Karl Richard Lepsius began an expedition up the Nile valley. Late on 28 January 1844 he reached Meroë in what is now Sudan and found a scattering of pyramids. But even by the light of his candle, he could see the structures weren’t as old as he had hoped. As he investigated further, he concluded they weren’t Egyptian.
Lepsius later drew a dividing line between ancient Egypt and the people who built the pyramids at Meroë, who belonged to a separate civilisation called Nubia. In the next century, researchers followed his lead and saw Egypt as sophisticated, and Nubia as its inferior neighbour. Egyptian artefacts were given pride of place in museums, Nubian work was largely ignored.
But attitudes are changing. Fresh research is bringing ancient Nubia out of the shadows and its story can now be told. These were diverse peoples with their own beliefs and customs. Far from being a boring backwater to Egypt, the Nubians exchanged cultural ideas with their neighbours, even setting fashion trends for kings like Tutankhamun. … More

By David Stock
In 2020, a chemical explosion in Beirut caused 218 deaths and widespread destruction. It also shattered one of the world’s richest collections of ancient glassware, offering experts the chance to analyse the artefacts in ways that would otherwise have been impossible

Tags: More

In 2020, a chemical explosion in Beirut caused 218 deaths and widespread destruction. It also shattered one of the world’s richest collections of ancient glassware, offering experts the chance to analyse the artefacts in ways that would otherwise have been impossible

Humans

29 September 2022

By James Dacey
Early to mid Roman-period glass bowl; bell-shaped flask from Islamic Golden Age; late Roman-period small cup;high-necked jug with turquoise tint from early Roman periodThe Archaeological Museum, American University of Beirut
PICTURE a 2000-year-old glass jug – turquoise tint, elegant spout. It probably decanted wine at lavish Roman banquets, surviving earthquakes and war before finding itself standing among similarly beautiful, delicate pieces in the American University of Beirut (AUB) Archaeological Museum in Lebanon. Then, in an instant, it shatters.

At least 218 people died and thousands more were injured when a giant pile of ammonium nitrate exploded at the port of Beirut on 4 August 2020. The blast was one of the largest non-nuclear, human-made explosions recorded, and the subsequent shock wave wreaked devastation for kilometres around.
The incident was also a cultural calamity. The wider region around Lebanon is touted as the crucible of glass production, a material that has helped shape civilisation. As one of the oldest museums in the area, the AUB housed a particularly rich collection of ancient glass artefacts. The blast smashed 72 jars, bowls, cups and other vessels dating back to the ancient Romans (1st century BC to 5th century AD), the Byzantine Empire (4th to 15th century AD) and the Islamic Golden Age (8th to 13th century AD).
A pile of ammonium nitrate exploded in Beirut, Lebanon, on 4 August 2020. The blast killed 218 people and injured thousandsANWAR AMRO/AFP via Getty Images
Rather than try to fix everything, however, AUB Archaeological Museum curator Nadine Panayot saw an opportunity in the debris. Much … More

A great corn on the cob must tread the line between under- and overcooked. Here’s why – and how to do it

Humans

28 September 2022

By Sam Wong
New Africa/Shutterstock
FRESH sweetcorn is one of the delights of late summer and early autumn. Its sweetness derives from a genetic variant that emerged some time after corn was first domesticated by people in Central America, about 9000 years ago. This mutation, called su1, stops the plant turning sugar into starch while it grows. Some sugar is instead converted into a different carbohydrate, phytoglycogen, which gives sweetcorn its creamy texture.
After harvesting, enzymes begin converting the sugar into starch, so sweetcorn is best eaten on the day it is picked. Some older varieties of corn can lose as much as half of … More

Saving unusual vegetable varieties from extinction is essential for protecting crop diversity, which is under threat from mechanisation, argues Adam Alexander in his richly detailed new book

Humans

28 September 2022

By Chris Stokel-Walker
Adam Alexander seeks out unusual seeds in Luang Prabang market, LaosJulia Alexander
The Seed Detective
Adam Alexander (Chelsea Green Publishing)
CATACLYSMIC headlines about food shortages, broken supply chains and overwhelming heat in the past few months have brought more awareness of where our food comes from. But decades of industrialisation of production have ensured we are still relatively detached from what we eat.
Award-winning film and TV producer Adam Alexander wants to fix that, as he makes clear in his book The Seed Detective: Uncovering the secret histories of remarkable vegetables. … More

Who and what will we become as the future unfolds? Anti-Body at Sadler’s Wells Theatre in London is a dance work that uses motion-capture tech to show how our influence extends beyond our physical bodies into the digital world

Humans

28 September 2022

By Alexandra Thompson
The “dancing” visuals in Anti-Body are created by motion-capture techSodium Bullet
Anti-Body
Alexander Whitley Dance Company
Lilian Baylis Studio, Sadler’s Wells Theatre, London, from 6 to 8 October
IN HIS book Homo Deus, writer Yuval Noah Harari asks: “Are organisms just algorithms and is life just data processing?” Is it possible that the human mind could one day be downloaded onto a computer chip?
This existential, unsettling idea is key to Anti-Body, a new dance work from the Alexander Whitley Dance Company, which has its London premiere next week.
At a recent … More

The standard “one-size-fits-all” approach to diagnosing and treating mental health problems is failing. Personalised treatments could make a big difference

Humans

| Leader

28 September 2022

By New Scientist
Natalia Klenova/EyeEm/Alamy
THERE can be few things more debilitating than going to bed, after a long and tiring day, and being unable to drift off. The harder you try to fall asleep, the more difficult it becomes – a vicious cycle of unwanted wakefulness that takes a significant toll on the lives of millions.
But it doesn’t have to be this way, because a new, more nuanced understanding of insomnia has made it a solvable problem, as we report in our cover story. Underlying this improved understanding is the recognition that there isn’t one type of insomnia but many – a departure … More