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Category: Evolution

How farming changed us: Ancient DNA reveals natural selection sped up in recent human evolution

How farming changed us: Ancient DNA reveals natural selection sped up in recent human evolution

Harvard Medical School: A massive study of ancient DNA from nearly 16,000 people across more than 10,000 years in West Eurasia reveals that natural selection has shaped modern human genomes far more than previously thought. Before now, studies of ancient human DNA had identified only about 21 instances of directional selection—the type of natural selection that occurs when one version of a gene that confers an extreme form of a trait, such as lactose tolerance after infancy, proves advantageous enough…

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‘First contact’ that may have led to complex life on Earth finally witnessed by scientists

‘First contact’ that may have led to complex life on Earth finally witnessed by scientists

Microscopic image showing newly discovered Asgard archaeon (Nerearchaeum marumarumayae) derived from microbial mats that offers clues to the formation of complex life. Debnath Ghosal By Brendan Paul Burns, UNSW Sydney and Kymberley Oakley, Indigenous Knowledge On the shores of the west coast of Australia lies a window to our past: the stromatolites and microbial mats of Gathaagudu (Shark Bay). To the untrained eye they look like a collection of rocks and slime – but they are in fact teeming with…

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We are all collections of errors

We are all collections of errors

Jerome Groopman writes: As I am writing this, my DNA is changing. And, as you read this, so is yours. People tend to assume that the genes we inherit from our parents are a fixed blueprint for our growth and development, immutable throughout our lives, and that the DNA in each cell of our body is the same as in every other cell. In fact, changes in our DNA, known as mutations, occur from the time we are in the…

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Disorder drives one of nature’s most complex molecular machines

Disorder drives one of nature’s most complex molecular machines

Yasemin Saplakoglu writes: At the dawn of complex life, evolution created a container for DNA, its most treasured item. A few billion years later, 20th-century microscopists looked at this container — the nucleus — up close and saw that it was covered in tiny openings. At the time, they didn’t know what to make of these structures, but as microscopy improved, something grand came into focus: what we now call “nuclear pore complexes,” some of the largest and most marvelous…

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How the harsh icy world of Snowball Earth shaped life today

How the harsh icy world of Snowball Earth shaped life today

Graham Shields writes: As Scotland’s west coast recedes from view, the ocean resembles a mirror, broken only by the swash of the boat and the dolphins chasing us. We’re headed to the craggy, uninhabited islands known as the Garvellachs. Only reachable during Scotland’s short summer, there is nothing between here and North America, and so landing – or rather jumping hopefully onto slippery rocks – is dependent on the kindness of the Atlantic swell. We’ve come to see a globally…

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Institutions are how we scale up cooperation among millions

Institutions are how we scale up cooperation among millions

Julien Lie-Panis writes: Every human society, from the smallest village to the largest nation, faces the same fundamental challenge: how to get people to act in the interests of the collective rather than their own. Fishermen must limit their catch so fish stocks don’t collapse. People must respect others’ property and safety. Citizens must pay taxes to fund roads, schools and hospitals. Left to pure self-interest, no community could endure; the bonds of collective life would quickly unravel. The solutions…

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We cooperate to survive, but if no one’s looking, we compete

We cooperate to survive, but if no one’s looking, we compete

Jonathan R Goodman writes: Reading classic works in evolutionary biology is unlikely to make you optimistic about human nature. From Charles Darwin’s The Descent of Man (1871) onwards, there is a fundamental understanding among biologists that organisms, especially humans, evolved to maximise self-interest. We act to promote our own success or that of our family. Niceness, by contrast, is just a mirage, and morality more broadly is just an illusion. Sociobiology – the infamous movement of the second half of…

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Microbes may hold the key to brain evolution

Microbes may hold the key to brain evolution

Northwestern University: A groundbreaking new study reveals that changes to the gut microbiome can change the way the brain works. Humans have the largest relative brain size of any primate, but little is known about how mammals with larger brains evolved to meet the intense energy demands required to support brain growth and maintenance. A new study from Northwestern University provides the first empirical data showing the direct role the gut microbiome plays in shaping differences in the way the…

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Flat Earth, spirits and conspiracy theories – experience can shape even extraordinary beliefs

Flat Earth, spirits and conspiracy theories – experience can shape even extraordinary beliefs

A belief in ghosts could be a way to explain a strange experience while asleep. ‘The Nightmare’ by Johann Heinrich Füssli/Wikimedia Commons By Eli Elster, University of California, Davis On Feb. 22, 2020, “Mad” Mike Hughes towed a homemade rocket to the Mojave Desert and launched himself into the sky. His goal? To view the flatness of the Earth from space. This was his third attempt, and tragically it was fatal. Hughes crashed shortly after takeoff and died. Hughes’ nickname…

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The discovery of aeonophiles expands our definition of life

The discovery of aeonophiles expands our definition of life

Karen G Lloyd writes: If you had to nominate the slowest, longest-living organisms on Earth, what would you picture? Among the vertebrates, some people might think of tortoises, whales or perhaps more obscure creatures like the Greenland shark, which can live for centuries. Others might imagine coral colonies, or perhaps an ancient tree: there are oaks in England that could be more than 1,000 years old, whereas in California, a few Bristlecone pines have been around for millennia, dating to…

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A cell that lacks any metabolic genes is a new addition to the spectrum of life

A cell that lacks any metabolic genes is a new addition to the spectrum of life

Jake Buehler writes: Life’s fundamental structure is the cell, and so the main things that a cell does — processing biomolecules, growing, replicating its genetic material and producing a new body — are considered hallmarks of life. But earlier this year, scientists discovered a cell so severely stripped of essential functions that it challenges biologists’ definitions of what counts as a living thing. The species is a single-celled organism known only by the mysterious sequence of its genetic code. Its…

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The evolving science of dietary restriction

The evolving science of dietary restriction

Andrew Steele writes: The idea that eating less might make us live longer has been around for thousands of years. Even Hippocrates, the Ancient Greek physician, argued that, “When a patient is fed too richly, the disease is fed as well. Any excess is against nature.” Scientists have now spent decades testing whether his advice holds true. The first striking evidence came in the 1930s, when American nutritionist Dr Clive McCay found that rats fed a restricted diet lived almost…

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What is sleep?

What is sleep?

Vladyslav Vyazovskiy writes: After decades of research, there is still no clearly articulated scientific consensus on what sleep is or why it exists. Yet whenever sleep comes up as a topic of discussion, it is quickly reduced to its necessity and importance. Popular media remind us of what can, and will, go wrong if we do not sleep enough, and serve up some handy tips on how to overcome insomnia. Discussed exclusively in utilitarian terms, we are force-fed the idea…

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Tiny tubes in primitive Asgard archea may have been the precursor of our own cellular skeletons

Tiny tubes in primitive Asgard archea may have been the precursor of our own cellular skeletons

Veronique Greenwood writes: In 2010, biologists made a shocking discovery. Living in the mud of the North Sea were microorganisms whose genes looked a lot like ours. Genetic analysis revealed that humans, oak trees, blue whales — any living things whose cells have nuclei and mitochondria — are related to these microbes, which were named the Asgard archaea after the home of the Norse gods. Two billion years ago, it was an ancestor of an Asgard that diverged from its…

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The sudden surges that forge evolutionary trees

The sudden surges that forge evolutionary trees

Jake Buehler writes: Over the last half-billion years, squid, octopuses and their kin have evolved much like a fireworks display, with long, anticipatory pauses interspersed with intense, explosive changes. The many-armed diversity of cephalopods is the result of the evolutionary rubber hitting the road right after lineages split into new species, and precious little of their evolution has been the slow accumulation of gradual change. They aren’t alone. Sudden accelerations spring from the crooks of branches in evolutionary trees, across…

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Here’s how the first proteins might have assembled, sparking life

Here’s how the first proteins might have assembled, sparking life

Science reports: Life today depends on proteins, cellular workhorses that do everything from flex muscles to ferry oxygen. And proteins, in turn, depend on RNA, which carries the recipes for making them and also helps with their assembly. In modern cells, large protein-based enzymes help connect RNA snippets to amino acids, the building blocks of proteins. Then, the RNA- and protein-based cellular machine called the ribosome stitches the amino acids together into a protein chain, reading the correct sequence from…

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