Category: survival

It Is Impossible to Predict How Humans Will Evolve

We all know what Neanderthals looked like: the beetling brow ridges, thick nose, long skull, massive bone structure – and probably red hair and freckled skin. You might do a double-take if you saw one on the subway, wearing a suit, or you might not. But you would surely look twice at the hunter-gatherers that populated Europe between 7,000 and 8,000 years ago, whose DNA scientists are analysing now. They had dark skin and, very likely, bright-blue eyes, like the beautiful child from Afghanistan you see in the photograph above. This combination essentially vanished from ancient Europe, replaced by light-skinned, brown-eyed farmers who moved in from the Middle East over the course of several centuries, and who looked like most of the population of southern Europe today.

These early farmers, who depended on milk, have the gene for lactose tolerance that is missing in the old hunter-gatherer population. They ate much less meat and far more starch than the original meat-eating Europeans, and depended both on milk and on sunlight for vitamin D – hence their lighter skin. As for the dark, blue-eyed people, they disappeared from Europe, swamped genetically by the invaders over time.

This is a tale of fast human evolution. New ways of living – farming crops, and herding animals rather than hunting – led to the rapid expansion of genes that took advantage of these cultural adaptations. The ancestral dark skin, probably inherited from our common forebears in Africa, could have been a disadvantage if most calories came from cultivated grains rather than meat from wild animals, rich in vitamin D. Blue eyes remained, though the form of the gene (called an allele) for blue eye colour is recessive, and easily swamped by alleles for brown eyes. So within some span of time – we can’t say exactly how long – ancient Europeans began to look quite different. There was also an influx of genes from east Asia, from peoples likely resembling the modern Chukchi and other native Siberian groups closely related to Native Americans. Ancient Europe was a melting pot, but certain alleles, for light skin and brown eyes, became dominant as the hunter-gatherer way of life receded against an influx of farmers and farming.

Image source: Nik.vuk/Wikimedia Commons

We think of evolution, described by Charles Darwin in 1859, as a slow dance: nature chooses the best-adapted organisms to reproduce, multiply and survive in any given ecosystem. As organisms adapt to changing ecological circumstances over millennia, the varieties best-suited to the environment thrive, allowing species to emerge and evolve. This is the process known as natural selection, or differential reproduction, which simply means that the organisms best-adapted to their particular, immediate circumstances will pass on more genes to the next generation than their less-well-adapted conspecifics (members of the same species).

Permanent change, of the kind we see in the fossil record, takes more time. Just look at the plodding trajectory of the several-hoofed Hyracotherium, a dog-sized forest-dwelling mammal that gradually lost its side toes (four on the front legs and three on the back) as the central one enlarged. It took 55 million years for it to evolve into the large, single-hoofed, grass-feeding horse we know today.

But sometimes evolution happens fast. As the biologists Peter and Rosemary Grant at Princeton University in New Jersey showed in their studies of Galapagos finches, small beaks can change into large beaks in a single generation, depending on climate conditions and the type of food to be found on those harsh islands. The small-beaked birds might die out, while the large-beaked prevail, for a while at least. But those rapid changes aren’t often permanent. Though the Grants might have witnessed the evolution of an entirely new, heavy-bodied finch species, many of the changes they saw in finches’ beaks were reversed, again and again. Changes in vegetation could mean that large beaks become a handicap. This shifting process – small changes over short periods of time – is called ‘microevolution’.

The evolutionary biologists David Lahti of Queens College at the City University of New York and Paul W Ewald of the University of Louisville both argue that there’s nothing exceptional about fast evolution. Rapid change, transient or lasting, simply reflects the intensity of selection, the strong action of Darwin’s ‘hostile forces of nature’, including predation, heat, cold, parasites. Difficult times could mean extinction for some species, or fast evolution for others. But to enable fast evolution, you must have enough genetic variation present in the underlying gene pool for selection to work upon. Hence the swift replacement of the hunter-gatherer with the farmer in ancient Europe. Light-skin genes overtook dark-skin genes because, likely, those genes better fit both the European environment and a new way of life.

Lahti adds that for human populations social selection becomes paramount: the presence of other hostile groups and the human ability for in-group cooperation drove the emergence of human social complexity and the evolution of the human brain. We don’t know whether the contact between European hunters and Middle Eastern farmers (or the East Asian people who also contributed their genes to the European pot) were friendly or hostile. Likely, in ancient Europe, there were skirmishes; likely, also, there were peaceful exchanges. We can’t know: all we see is the result, the apparent swamping of one set of traits for others that gradually became fixed in the area.

Of course, blond hair and light skin came to characterise Europe in the far north, among the ancestral Scandinavian population; pale skin here is likely an adaptation to vitamin D shortage. Dark skin remains a useful adaptation in hot, sunny climates. As climate changes, perhaps local variations in human appearance will be favoured in ways we don’t yet know.

Human evolution and the forces that produce it have never stopped. Some people will always be favoured genetically, and their offspring will be more likely to survive. That’s the essence of natural selection. And so adaptation and human evolution go on all the time. As a species, it’s impossible to say that we’re evolving in a particular direction – towards bigger heads and spindly limbs, say, as science fiction often suggests. But on the local level, adaptation and natural selection are always at work, adapting us to combat whatever threats – new diseases, climate change, new social selection processes – are now, often invisibly, at hand.Aeon counter – do not remove

Wendy Orent

This article was originally published at Aeon and has been republished under Creative Commons.

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If We Survive Another Billion Years, What Will Life Be Like?

Here’s an interesting thought: what if humanity manages to survive one billion years from now? Would we finally be an interplanetary species, conquering Mars and other cosmic objects in our Solar System — or beyond? This is an idea that RealLifeLore explores in the video below.

Of course, there’s no way we could really tell what’s going to happen a billion years from now. So, all of the events featured in the video are purely evidence-based speculations. They’re plausible based on what we currently know, but we could never be sure of these predictions. However, it’s worth traveling forward in time, at least visually, to explore.

For one, in this future prediction, it is most likely that there will be a lot of cataclysmic extinction events. In 10,000 AD, a new, perhaps more realistic, version of Y2K could cause the failure of computers and all that depends on them — which, by then, would most likely be literally everything. There is even the possibility that a couple of asteroid collisions and a solar burst that could make life on Earth impossible a few thousand years later.

However, aside from all of these potential threats, there are also really exciting events worth looking forward to. Mars could finally be livable thanks to terraforming by 100,000 AD, and other planets could be colonized as well, some years later — possibly creating a political situation similar to the one in the science fiction show The Expanse. By 2,000,000 AD, with humanity colonizing the Solar System, humankind could evolve into entirely different species — assuming we haven’t already, thanks to advances in artificial intelligence leading to the melding of humans and machines.

In any case, if humanity does survive the next billion years, it would probably be because of the ingenuity that humankind is known for. Who knows, it might just be possible.

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These Researchers Want to Prepare Us for the Post-Apocalypse

OK, we survived the cataclysm. Now what?

In recent years, warnings by top scientists and industrialists have energized research into the sort of civilization-threatening calamities that are typically the stuff of sci-fi and thriller novels: asteroid impacts, supervolcanoes, nuclear war, pandemics, bioterrorism, even the rise of a super-smart, but malevolent artificial intelligence.

But what comes afterward? What happens to the survivors? In particular, what will they eat? How will they stay warm and find electricity? How will they rebuild and recover?

These “aftermath” issues comprise some of largest points of uncertainty regarding humanity’s gravest threats. And as such they constitute some of the principal research focuses of the Global Catastrophic Risk Institute (GCRI), a nonprofit think tank that Seth Baum and Tony Barrett founded in late 2011. Baum, a New York City-based engineer, and geographer is GCRI’s executive director. Barrett, who serves as its director of research, is a senior risk analyst at ABS Consulting in Washington, DC, which performs probabilistic risk assessment and other services.

Black Swan Events

At first glance, it may sound like GCRI is making an awful lot of fuss about dramatic worst-case scenarios that are unlikely to pan out anytime soon. “In any given year, there’s only a small chance that one of these disasters will occur,” Baum concedes. But the longer we wait, he notes, the greater the chance that we will experience one of these “Black Swan events” (so called because before a black swan was spotted by an explorer in the seventeenth century, it was taken for granted that these birds did not exist). “We’re trying to instill a sense of urgency in governments and society in general that these risks need to be faced now to keep the world safe,” Baum says.

GCRI’s general mission is to find ways to mobilize the world’s thinkers to identify the really big risks facing the planet, how they might cooperate for optimal effect, and the best approaches to addressing the threats. The institute has no physical base, but it serves as a virtual hub, assembling “the best empirical data and the best expert judgment,” and rolling them into risk models that can help guide our actions, Barrett says. Researchers, brought together through GCRI, often collaborate remotely. Judging the real risks posed by these low-odds, high-consequence events is no simple task; he says: “In most cases, we are dealing with extremely sparse data sets about occurrences that seldom, if ever, happened before.”

These Researchers Want to Prepare Us for the Post-Apocalypse

 

Beyond ascertaining which global catastrophes are most likely to occur, GCRI seeks to learn how multiple events might interact. For instance, could a nuclear disaster lead to a change in climate that cuts food supplies while encouraging a pandemic caused by the loss of medical resources? “To best convey these all-too-real risks to various sectors of society, it’s not enough to merely characterize them,” Baum says. Tackling such multi-faceted scenarios requires an interdisciplinary approach that would enable GCRI experts to recognize potential shared mitigation strategies that could enhance the chances of recovery, he adds.

One of the more notable GCRI projects focuses on the aftermath of calamity. This analysis was conducted by research associate Dave Denkenberger, who is an energy efficiency engineer at Ecova, an energy and utility management firm in Durango, Colorado. Together with engineer Joshua M. Pearce, of Michigan Technological University in Houghton, he looked at a key issue: If one of these catastrophes does occur, how do we feed the survivors?

Worldwide, people currently eat about 1.5 billion tons of food a year. For a book published in 2014, Feeding Everyone No Matter What: Managing Food Security After Global Catastrophe, the pair researched alternative food sources that could be ramped up within five or fewer years following a disaster that involves a significant change in climate. In particular, the discussion looks at what could be done to feed the world should the climate suffer from an abrupt, single-decade drop in temperature of about 10°C that wipes out crops regionally, reducing food supplies by 10 per cent. This phenomenon has already occurred many times in the past.

Sun Block

Even more serious are scenarios that block the sun, which could cause a 10°C temperature drop globally in only a single year or so. Such a situation could arise should smoke enter the stratosphere from a nuclear winter resulting from an atomic exchange that burns big cities, an asteroid or comet impact, or a supervolcano eruption such as what may one day occur at Yellowstone National Park.

These risks need to be faced now to keep the world safe. – Seth Baum

Other similar, though probably less likely, scenarios, Denkenberger says, might derive from the spread of some crop-killing organism—a highly invasive superweed, a superbacterium that displaces beneficial bacteria, a virulent pathogenic bacterium, or a super pest (an insect). Any of these might happen naturally, but they could be even more serious should they result from a coordinated terrorist attack.

“Our approach is to look across disciplines to consider every food source that’s not dependent on the sun,” Denkenberger explains. The book considers various ways of converting vegetation and fossil fuels to edible food. The simplest potential solution may be to grow mushrooms on the dead trees, “but you could do much the same by using enzymes or bacteria to partially digest the dead plant fiber and then feed it to animals,” he adds. Ruminants including cows, sheep, goats, or more likely, faster-reproducing animals like rats, chickens or beetles could do the honors.

A more exotic solution would be to use bacteria to digest natural gas into sugars, and then eat the bacteria. In fact, a Danish company called Unibio is making animal feed from commercially stranded methane now.

Meanwhile, the U.S. Department of Homeland Security is funding another GCRI project that assesses the risks posed by the arrival of new technologies in synthetic biology or advanced robotics which might be co-opted by terrorists or criminals for use as weapons. “We’re trying to produce forecasts that estimate when these technologies might become available to potential bad actors,” Barrett says.

Focusing on such worst-case scenarios could easily dampen the spirits of GCRI’s researchers. But far from fretting, Baum says that he came to the world of existential risk (or ‘x-risk’) from his interest in the ethics of utilitarianism, which emphasizes actions aimed at maximizing total benefit to people and other sentient beings while minimizing suffering. As an engineering grad student, Baum even had a blog on utilitarianism. “Other people on the blog pointed out how the ethical views I was promoting implied a focus on the big risks,” he recalls. “This logic checked out and I have been involved with x-risks ever since.”

Barrett takes a somewhat more jaundiced view of his chosen career: “Oh yeah, we’re lots of fun at dinner parties…”

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