Philippa Kaur

This evolution bestseller is full of ironic humour, sharp insights and affectionate acknowledgement of human flaws – and ends up as a celebration of curiosity

Humans

27 July 2022

By Rebecca Wragg Sykes
Excavations at Atapuerca, near Burgos, Spain, shed new light on the first humans in Europeagefotostock/Alamy
Life As Told By a Sapiens to a Neanderthal
Juan José Millás and Juan Luis Arsuaga (translated by Thomas Bunstead and Daniel Hahn)
Scribe
IN THE Spanish city of Burgos, a towering 13th-century Gothic cathedral stands opposite the Museum of Human Evolution. Built 800 years apart, these buildings are both dedicated to finding meaning and exploring human origins, but the bones in the museum are 1000 times older than the cathedral, and its “high priest” … More

Artificial turf has grown in popularity, but it has major drawbacks, says Beronda L. Montgomery, who is looking for a sustainable alternative

Humans

| Columnist

27 July 2022

By Beronda L. Montgomery
Olga Prava/Shutterstock
I RECENTLY stood surveying my new front lawn with a landscaper. The grass is a fine-bladed fescue variety that grows slowly, partly because it is a shade-tolerant species situated beneath the cover of my front yard’s large oak trees. These grasses are efficient at photosynthesis and can produce enough sugars to grow in limited light.
It is important to know whether your lawn is populated by sun-loving or shade-tolerant plants because they have different nutrient requirements. All plants have relatively high nitrogen needs because chlorophyll, which is central to photosynthesis, contains nitrogen. Shade-tolerant varieties, however, generally have lower nitrogen … More

Shutterstock/Bangkok Click Studio
I AM a science teacher and I think anyone who spends time with young children can be one too. It is in the home that children first encounter literature, maths, music and art – through reading, counting, singing and drawing. But this sort of informal teaching isn’t so common when it comes to science. That is partly because many people lack the knowledge or confidence to talk about science with children, and partly because science isn’t ingrained in our culture in quite the same way.
Some children do try out “experiments” at home, such as making a “volcano” using bicarbonate of … More

Visit
Zero to Birth reveals how the brain is built, as neurobiologist William Harris explores the development of the human brain in utero and a bit beyond. Catch it live at the Royal Institution, London, at 7pm BST on 8 August.

Read
The Uses of Delusion are manifold, says psychologist Stuart Vyse. In this new book, he connects research into illogical thinking with its evolutionary origins and explains the possible benefits of irrational behaviour. On sale from 1 August.

Watch
The Sandman stars Tom Sturridge as the titular lord of dreams, imprisoned by … More

Archaeological and genetic evidence casts doubt on the idea that the ability to digest lactose after infancy evolved gradually

Humans

27 July 2022

By Luke Taylor
Neolithic people began drinking milk around 7000 BCCHRISTIAN JEGOU/SCIENCE PHOTO LIBRARY
Milk consumption was widespread thousands of years before people were able to break it down properly, according to the largest study yet on the evolution of lactose tolerance in humans. The ability to break down lactose was probably gained during episodes of acute crisis, not gradually over time, the study found.
As babies, all humans produce the enzyme lactase, which breaks down lactose into the more readily absorbed glucose and galactose, but many people have much lower levels of lactase after weaning, meaning they cannot digest milk properly.
The spread of lactase persistence – the ability to break down lactose after weaning – is considered one of the best examples of natural selection in humans. One-third of the global population gained this trait in just a couple of thousand years.Advertisement
The leading explanation was that humans gained lactase persistence so quickly as their evolution was deeply intertwined in a cycle with dairy. As humans were pressured into evolving lactase persistence due to the nutritional benefits of milk, the spread of lactase persistence would have in turn increased human reliance on milk, increasing the pressure to be lactose tolerant.
Richard Evershed at the University of Bristol, UK, and his colleagues studied 7000 animal fat residues that had seeped into pottery at 500 sites across Europe. This revealed that dairy farming was common in the region from 7000 BC onwards.
But ancient DNA evidence revealed that lactase persistence wasn’t prevalent until around 1000 BC — roughly 4000 years after the trait was first detected and 6000 years after milk production took hold.
There are many ideas as to why lactose tolerance developed so rapidly, ranging from the benefits of milk’s sugar content to vitamin D, but they “all go out the window because they are all pinned to milk use in one way or another”, Mark Thomas of University College London, a co-author of the study, told a press briefing.
Mapping the use of milk across Europe against the spread of lactase persistence showed no correlation, while computer models suggest that famine and disease offer better explanations.
Using changes in population size as a proxy for malnutrition, the researchers found lack of food was 689 times more likely to explain the rise of lactose tolerance than constant selection pressure. Using population density as a proxy for the spread of deadly pathogens, they found that disease was 289 times more likely to account for the spread.
During these periods of crisis, the flatulence, stomach cramps or diarrhoea experienced by lactose intolerant people probably turned into a life or death matter, said Thomas.

An analysis of health and genetic data from the UK Biobank also suggested that the co-evolution idea for humans and lactose tolerance is unlikely.
Lactose tolerant people would be expected to have higher levels of some health metrics, such as bone mineral density, height or vitamin D, Thomas said, but the researchers found none except for slightly higher body mass index numbers.
Surprisingly, there was also little difference in the proportion of people who don’t drink cow’s milk amongst the lactose tolerant and intolerant: 6.8 per cent versus 8 per cent.
The results suggest that many people should consider drinking milk for its nutritional benefits, even if they are lactose intolerant, Evershed said at the briefing. “Broadly, if you’re lactose non-persistent it isn’t necessarily such a big deal.”
The negative symptoms associated with milk consumption only occur in some people who are lactose intolerant, probably due to variations in bacteria in the colon. Some people who experience side effects may be confounding lactose intolerance with milk allergy, the researchers said.
Journal reference: Nature, DOI: 10.1038/s41586-022-05010-7
Sign up to Our Human Story, a free monthly newsletter on the revolution in archaeology and human evolution

More on these topics: More

From sci-fi classics to essential non-fiction, some of the brightest minds in science, including Sarah Gilbert and Jim Al-Khalili, share their top picks for holiday reading

Humans

22 July 2022

By New Scientist
L to R: Jim Al-Khalili, Pragya Agarwal, Guy Leschziner, Robert Macfarlane, Sarah Gilbert, Peter Marren, Yuval Noah Harari
We asked writers and scientists including Robert Macfarlane, Pragya Agarwal and Peter Marren to tell us what books they were planning to take away with them this year. And if their picks don’t make it into your packing, then why not try our round-up of the best science non-fiction to read on holiday and our picks of the year’s best science fiction to date?
Jim Al-Khalili is a physicist and the author of … More

Whether it is the science of sleep, the physics that changed the world or the inner lives of bees, we’ve got you covered for holiday reading

Humans

21 July 2022

By Liz Else
NDinfinity/getty images
ONE of the best things about science books is that there is always something new and marvellous to savour when you have enough time. Those who are lucky enough to be going on holiday are spoiled for choice: there has been a book bonanza so far this year from both established heavy hitters and challenging newcomers.
Starting with the ever-popular dinosaurs, Riley Black’s The Last Days of the Dinosaurs is a vivid glimpse into the period just before (and just after) the worst day ever for life on Earth, when a 10-kilometre-wide asteroid ploughed into what is now Yucatán, … More