How About a New Theory of Evolution with Less Natural Selection?

Biologists debate adding a controversial new aspect to the understanding of evolution.


In early November, a group of preeminent biologists, doctors, anthropologists, and computer scientists met in London to consider making a major change to the concept of evolutionary biology introduced by Charles Darwin in Origin of the Species in 1859. It’s not that they’re interested in throwing out the idea of natural selection. It’s just that they think recent research suggests it doesn’t account for evolution all by itself. This isn’t the first time such a revision has happened, actually. And it’s not clear that it will this time: Conference co-host Kevin Laland told Quanta magazine mid-conference, “I think it’s going quite well,” Laland said. “It hasn’t gone to fisticuffs yet.”

The current understanding of evolution, known as “modern evolutionary synthesis,” is itself a combination of natural selection and the 1865 genetics work of Gregor Mendel, published six years after Origin of the Species.

Mendel’s peas

The modern synthesis emerged in the 1930s and 1940s, and it’s what’s taught in schools today. It states that evolution is the product of small genetic variations (Mendel’s contribution) that survive, or not (Darwin’s process of natural selection).

Some of the scientists at the Royal Society’s “New Trends in Evolutionary Biology” meeting say that this isn’t quite the case, and that there’s a third element that needs to be incorporated: Behavior and environment can also cause evolutionary changes. Carl Zimmer of Quanta, who attended the conference, says, "The researchers don’t argue that the modern synthesis is wrong — just that it doesn’t capture the full richness of evolution.”

To that end some attendees at the conference proposed a new understanding they call the “extended evolutionary synthesis.” What it adds to Darwin’s and Mendel’s work is an awareness of epigenetics.

The word “epigenetics” means “in addition to changes in genetic sequence.” According to science journalist Tabitha M. Powledge, “Broadly speaking, epigenetics is how nurture shapes nature.” The field looks at inheritable genetic changes that don’t involve the changing of a DNA sequence, but rather the activation or deactivation of genes via the epigenome, a layer of chemical tags covering and shaping the structure of a genome to turn individual genes on or off depending on the purpose of a cell, using a variety of chemical processes. The University of Utah has a great video explaining what an epigenome is.

Epigenetic mechanisms (NIH)

According to the University of Utah, “The epigenome dynamically responds to the environment. Stress, diet, behavior, toxins, and other factors regulate gene expression.” 

Scientists used to believe that when a offspring is born, it starts with a clean epigenomic slate. This turns out not to always be the case, at least in plants and fungi, and maybe in invertebrates. Some epigenetic tags survive, and thus “epigenetic inheritance” may play a role in the organism’s evolution. There’s some evidence it also occurs in vertebrates, but the jury is still out, and the presence of epigenetic inheritance is difficult to establish. A trait may turn out to be the result of obscure or subtle DNA changes, or a common environment may cause the persistence of a trait in a subsequent generation rather than epigenetic inheritance.

Still, epigeneticists hope the field can help explain evolutionary changes that don’t seem to be accounted for by modern evolutionary synthesis.

For example, speaking at the Royal Society was Melinda Zeder, who talked about the way in which modern synthesis fails to provide a reason for mankind’s turning to agriculture 10,00 years ago and its ensuing evolutionary impact. Growing crops may have taken years, so there could not have been a short-term evolutionary benefit to it. As Zeder told Quanta, “You don’t get the immediate gratification of grabbing some food and putting it in your mouth.” It’s also been theorized that a climate shift caused agriculture to bloom, but there’s no evidence of such a shift.

Zeder suggests we take a different view of humans at the time as creative individuals who deliberately decided to change their environment by farming, pushing human evolution in that new direction. This process is called “niche construction,” and it’s more than just a human behavior; think beavers and their dams.

Not everyone agrees that epigenetics warrants a revision to the understanding of evolution, and there were plenty of skeptics at the Royal Society conference. Not everyone agreed with the conclusions of some experiments that putatively demonstrated epigenetic at work, and others noted that epigenetics undervalues the flexibility, or “plasticity,” provided by plentiful genetic variations. Biologist Douglas Futuyma suggested the appeal of epigenetics was that it changes the organism from a passive receiver of genetics changes to an active participant in evolution. “I think what we find emotionally or aesthetically more appealing is not the basis for science,” he said.

As Laland noted to Quanta, “This is likely the first of many, many meetings.”

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The world's oceans will rise significantly over the next century if the massive ice shelves connected to Antarctica begin to fail as a result of global warming.

To prevent or hold off such a catastrophe, a team of scientists recently proposed a radical plan: build underwater walls that would either support the ice or protect it from warm waters.

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One approach involves using sand or gravel to build artificial mounds on the seafloor that would help support the glacier and hopefully allow it to regrow. In another strategy, an underwater wall would be built to prevent warm waters from eating away at the glacier's base.

The most effective design, according to the team's computer simulations, would be a miles-long and very tall wall, or "artificial sill," that serves as a "continuous barrier" across the length of the glacier, providing it both physical support and protection from warm waters. Although the study authors suggested this option is currently beyond any engineering feat humans have attempted, it was shown to be the most effective solution in preventing the glacier from collapsing.

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An example of the proposed geoengineering project. By blocking off the warm water that would otherwise eat away at the glacier's base, further sea level rise might be preventable.

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"The more carbon we emit, the less likely it becomes that the ice sheets will survive in the long term at anything close to their present volume."

A 2015 report from the National Academies of Sciences, Engineering, and Medicine illustrates the potentially devastating effects of ice-shelf melting in western Antarctica.

"As the oceans and atmosphere warm, melting of ice shelves in key areas around the edges of the Antarctic ice sheet could trigger a runaway collapse process known as Marine Ice Sheet Instability. If this were to occur, the collapse of the West Antarctic Ice Sheet (WAIS) could potentially contribute 2 to 4 meters (6.5 to 13 feet) of global sea level rise within just a few centuries."

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How a drought in the Middle East contributed to extremism in Europe

(DANIEL LEAL-OLIVAS/AFP/Getty Images)

Nigel Farage in front of a billboard that leverages the immigration crisis to support Brexit.

Because climate change is too big for the mind to grasp, we'll have to use a case study to talk about this. The Syrian civil war is a horrific tangle of senseless violence, but there are some primary causes we can point to. There is the longstanding conflicts between different religious sects in that country. Additionally, the Arab Spring swept Syria up in a wave of resistance against authoritarian leaders in the Middle East — unfortunately, Syrian protests were brutally squashed by Bashar Al-Assad. These, and many other factors, contributed to the start of the Syrian civil war.

One of these other factors was drought. In fact, the drought in that region — it started in 2006 — has been described as the "worst long-term drought and most severe set of crop failures since agricultural civilization began in the Fertile Crescent many millennia ago." Because of this drought, many rural Syrians could no longer support themselves. Between 2006 and 2009, an estimated 1.5 million Syrians — many of them agricultural workers and farmers — moved into the country's major cities. With this sudden mixing of different social groups in a country where classes and religious sects were already at odds with one another, tensions rose, and the increased economic instability encouraged chaos. Again, the drought didn't cause the civil war — but it sure as hell helped it along.

The ensuing flood of refugees to Europe is already a well-known story. The immigration crisis was used as a talking point in the Brexit movement to encourage Britain to leave the EU. Authoritarian or extreme-right governments and political parties have sprung up in France, Italy, Greece, Hungary, Slovenia, and other European countries, all of which have capitalized on fears of the immigration crisis.

Why climate change is a "threat multiplier"

This is why both NATO and the Pentagon have labeled climate change as a "threat multiplier." On its own, climate change doesn't cause these issues — rather, it exacerbates underlying problems in societies around the world. Think of having a heated discussion inside a slowly heating-up car.

Climate change is often discussed in terms of its domino effect: for example, higher temperatures around the world melt the icecaps, releasing methane stored in the polar ice that contributes to the rise in temperature, which both reduces available land for agriculture due to drought and makes parts of the ocean uninhabitable for different animal species, wreaking havoc on the food chain, and ultimately making food more scarce.

Maybe we should start to consider climate change's domino effect in more human and political terms. That is, in terms of the dominoes of sociopolitical events spurred on by climate change and the missing resources it gobbles up.

What the future may hold

(NASA via Getty Images)

Increasingly severe weather events will make it more difficult for nations to avoid conflict.

Part of why this is difficult to see is because climate change does not affect all countries proportionally — at least, not in a direct sense. Germanwatch, a German NGO, releases a climate change index every year to analyze exactly how badly different countries have been affected by climate change. The top five most at-risk countries are Haiti, Zimbabwe, Fiji, Sri Lanka, and Vietnam. Notice that many of these places are islands, which are at the greatest risk for major storms and rising sea levels. Some island nations are even expected to literally disappear — the leaders of these nations are actively making plans to move their citizens to other countries.

But Germanwatch's climate change index is based on weather events. It does not account for the political and social instability that will likely result. The U.S. and many parts of Europe are relatively low on the index, but that is precisely why these countries will most likely need to deal with the human cost of climate change. Refugees won't go from the frying pan into the fire: they'll go to the closest, safest place available.

Many people's instinctive response to floods of immigrants is to simply make borders more restrictive. This makes sense — a nation's first duty is to its own citizens, after all. Unfortunately, people who support stronger immigration policies tend to have right-wing authoritarian tendencies. This isn't always the case, of course, but anecdotally, we can look at the governments in Europe that have stricter immigration policies. Hungary, for example, has extremely strict policies against Muslim immigrants. It's also rapidly turning into a dictatorship. The country has cracked down on media organizations and NGOs, eroded its judicial system's independence, illegalized homelessness, and banned gender studies courses.

Climate change and its sociopolitical effects, such as refugee migration, aren't some poorer country's problem. It's everyone's problem. Whether it's our food, our homes, or our rights, climate change will exact a toll on every nation on Earth. Stopping climate change, or at least reducing its impact, is vitally important. Equally important is contending with the multifaceted threats its going to throw our way.