Humans

By Chelsea Whyte
Donald Trump signs an executive order on energy and infrastructure
Evan Vucci/AP/Shutterstock

AS US President Donald Trump prepares to face the ballot box in the hopes of winning a second term, his handling of the coronavirus pandemic will be at the forefront of voters’ minds. But Trump’s impact on health, space and environment policy during his time in office also warrants examining.
In the past four years, Trump has promised to reverse environmental regulations and climate change policy, to repeal and replace his predecessor Barack Obama’s landmark healthcare policy and to revive the fortunes of NASA. Has he succeeded?
A … More

By Donna Lu
Was Homo erectus driven extinct by climate change?
The Natural History Museum/Alamy

Sudden climatic changes may have been a significant driver of the extinction of early human species.
Pasquale Raia at the University of Naples Federico II in Italy and his colleagues have used climate modelling and fossil records to determine the effect climate change had on the survival of the species in our Homo genus.
The researchers used a database of 2754 archaeological records of the remains of several species alive over the past 2.5 million years, including Homo habilis, Homo ergaster, Homo erectus, Homo heidelbergensis, Homo neanderthalensis and Homo sapiens.

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They cross-referenced these records with a climate emulator, which modelled temperature, rainfall and other weather data over the past 5 million years. The aim was to determine the climatic niche for each species – a range of conditions including temperature and precipitation that are optimal for survival – and how widely distributed the niche area was through time.
The team found that H. erectus, H. heidelbergensis and H. neanderthalensis all lost a significant portion of their climatic niche area just before they became extinct.

“Species are good at surviving when they have a large area at their disposal to live in,” says Raia. But when liveable areas decrease and the result is small patches that are geographically isolated from each other, species enter what is known as an extinction vortex.
The reductions in liveable area resulted from sudden climatic changes, the team found. H. erectus, for example, went extinct during the last glacial period, which began about 115,000 years ago. The researchers suggest this was the coldest period the species had ever experienced.
The team found that for the Neanderthals, competition with H. sapiens was also a factor, but that even without the presence of our species the effect of climate change alone may have been enough to lead to extinction. Even species with the ability to control their local environment – such as by wearing clothes or creating fires – were susceptible to the effects of climate change, says Raia.

But gaps in data may compromise the certainty of the conclusion that climate change was the primary extinction driver, say researchers who weren’t involved in the study.

Aside from Neanderthals, there is scarcely any fossil evidence for the other species studied, says Bernard Wood at George Washington University in Washington DC. “Individuals belonging to these taxa lived at times, and in places, not sampled by the existing fossil record,” he says.
“Plus, the first appearance date of a taxon almost certainly underestimates when a taxon appeared, and its last appearance date almost certainly underestimates when a taxon became extinct,” he says.
As species approach extinction, regardless of the cause – whether it be competition, being hunted or breeding problems – their range necessarily declines, says Corey Bradshaw at Flinders University in Australia. If a species’ range was already in decline, that could give the false impression that the climate niche area was also declining, he says.
“No species that we know of has ever gone extinct from a single mechanism. It’s always a combination,” says Bradshaw. “For example, in the case of many megafauna species in the late Pleistocene, it’s coming to light that there were a lot of interaction effects between human hunting and climate change.”
Journal reference: One Earth, DOI: 10.1016/j.oneear.2020.09.007
More on these topics: More

Filler words such as uh, mmm and huh may seem inarticulate, but without them human communication would be far less sophisticated

Humans 14 October 2020
By David Robson

Andy Smith

YOU might expect it to take more than a two-letter word to sink a politician’s credibility. But one did just that for Canada’s prime minister, Justin Trudeau, in June 2016. With a huge wildfire burning in the province of Alberta, he had been asked about the country’s capacity to cope. “Uh, certainly, I think we’re, uh, all aware that, uh, uh, a prime minister, uh, showing up at Fort McMurray, when firefighters are busy trying to, uh, uh, contain a massive raging wildfire is, uh, not a particularly helpful thing,” he began. Trudeau went on to use a total of 50 uhs in a statement lasting little more than a minute.
A video soon went viral, and online commentators were universally scathing. “Canada’s dumbest, uh, Prime Minister” wrote one viewer. Reading the unedited transcript, you may well have questioned Trudeau’s intelligence yourself. Surely such hesitation is a sign of sloppy thinking and ineloquence. Weren’t we taught as children to eliminate uhs from our conversation?
Yet the latest research shows that this is an unfounded prejudice. Far from being an inarticulate waste of breath, filler words like um, uh, mmm and huh are essential for efficient communication, sending important signals about the words we are about to say so that two speakers can better understand each other. “They streamline our interactions, smooth the flow of the conversation and manage our social relations,” says Mark Dingemanse, who studies language and social interaction at Radboud University in the Netherlands. Indeed, he argues that the complexity of our language today couldn’t have emerged without them. To which the obvious response … More

The Book of Malachi by T. C. Farren centres on a young man whose tongue has been cut out during a brutal civil war. It’s a tough, mind-bending morality tale

Humans 14 October 2020

Victor Moussa/Alamy

The Book of Malachi
T. C. Farren
Titan
THE main problem with this book is you aren’t going to want to read it. But it’s good and you should.
Malachi Dakwaa, the eponymous character in T. C. Farren’s novel, is a young man whose tongue was cut out in a brutal civil war. In the years since, he has eked out a half-life as a quality control manager at a chicken processing plant, ensuring the uniform compliance of shrink-wrapped body parts.
One day, he gets an offer for a job he didn’t apply for, with a payment he … More

By Michael Marshall
View from the chamber entrance on Bengorm mountain, Ireland
Thorsten Kahlert

Some Stone Age people in Ireland left the bodies of their dead to decompose in a natural rocky chamber on a mountain. Genetic analysis of two of these bodies shows they had darker skin, like many people in Europe at the time, and suggests they lived in fairly large communities.
The boulder chamber was accidentally discovered in 2016 by a hillwalker exploring Bengorm mountain in north-west Ireland. Finding human bones on the floor, he called the police. The bones turned out to be thousands of years old and the … More

By Donna Lu
Don’t mind the smell of rotten fish? A genetic mutation may be to blame
Shutterstock / casanisa

If you don’t find the smell of fish particularly off-putting, you may have an olfactory gene mutation that makes these odours seem less strong and disagreeable.
Kári Stefánsson at Icelandic genomics firm deCODE Genetics and his colleagues have identified a gene, TAAR5, that affects how people perceive odours containing trimethylamine, a compound found in rotten and fermented fish.
To study how genetics affects our sense of smell, the researchers asked 9122 Icelandic adults to smell six odours that were presented in … More

By Colin Barras
The oldest balls found in Eurasia are leather sacks stuffed with leather strips or wool and hair
Patrick Wertmann

The first ball games in Eurasia may have been played 3000 years ago, according to a new analysis of three leather balls unearthed in an ancient cemetery in northern China. One of the men buried with a leather ball also sported the world’s earliest known pair of trousers, which he may have worn while playing.
The Yanghai cemetery, which contains more than 500 graves, was in use between about 3200 and 1850 years ago. A few years ago, archaeologists … More

Leonard Mlodinow’s book on his friendship with Stephen Hawking shows another side to the late physicist, including tales of punting in Cambridge and annoying a restaurant chef

Humans 7 October 2020
By Gege Li
Hawking said his medical condition helped his focus
NG Images/Alamy

WHEN physicist Stephen Hawking died in 2018 at the age of 76, the world mourned. But after the loss, there remains the enormous legacy of the scientist and the man to consider.
And what a legacy. Renowned for decades of work on cosmology and black holes, with A Brief History of Time selling more than 25 million copies since its release in 1988, Hawking reshaped our understanding of some of the trickiest areas in modern physics.
Among … More