We asked an evolution expert what will happen to humanity after the apocalypse

It’s been portrayed in fiction, films, TV shows and video games. But if and when the apocalypse finally descends upon our humble Earth, what will actually happen to everyone?

Will our great-great-great-grandkids survive a meteor collision like the one that killed the dinosaurs, or perish while a new species takes over? Could a few survivors eventually repopulate the Earth, perhaps evolving new bodily features that would be required to thrive in a post-apocalyptic world? Or will we leave our home behind and venture into space, hoping that another planet can sustain human life?

To find out the answers to all these questions, we spoke to Professor Mark Pagel, a leading evolutionary biologist and author of Wired For Culture, a book about the unique traits humans have evolved. Read on to find out whether robots will take over the world, what we could learn from alligators and why burrowing underground like a clan of mutant mole people might be our best chance of survival.


Love Nature: Hi Mark. What do you see as the most likely cause for a complete wipe-out of the human race?

Professor Mark Pagel: There are two aspects to this question: one is the probability of the causal event happening, the other is its lethality or potential for complete destruction. The usual main contenders for potentially devastating effects on the human race are climate change, food or energy shortages, nuclear war, antibiotic resistance or a pandemic virus, a global computer shutdown or attacks from rogue AI machines.

Each of these could happen and might even be relatively likely, but none is likely to wipe out the human race. By comparison a collision with a large asteroid, although very unlikely in the timeframe of our history as a species, could easily lead to our extinction.


When in the future do you predict that humans will face the threat of mass-extinction?

Mass-extinction (as opposed to complete extinction) could occur as a result of any of the causes mentioned above. It is not out of the question that the first of these could happen within 100 years. My own view is that they won’t, but given current trends, they could.

The key point is that I don’t think current trends will continue. Regarding a collision with a large asteroid, current models suggest the chances are small but this is a case of Donald Rumsfeld’s ‘unknown knowns’. We know that large asteroids exist, but we can never rule out that there is one coming our way that we don’t yet know about.


How likely is it that humans would survive an apocalypse—for example, something similar to the event that wiped out the dinosaurs?

Humans would almost certainly survive an event such as the asteroid impact that wiped out the dinosaurs, but globally billions of people would perish. In the case of an event even more catastrophic than that, even though billions of humans would perish, some of us would survive.

Life would become stone age-like but some remnants of humanity would survive. Under some scenarios, the more humans that die, the easier it becomes for the remainder to survive because food will become more plentiful, energy will become less scarce, there will be less strife and the rates of disease transmission will be lower.

On the other hand, the pool of shared knowledge will dwindle as more humans perish and this will make it more difficult for the survivors.


In the event of almost complete extinction, would humans be able to recover?

Yes, we would. We would recover by the slow accumulation of knowledge, technology and skills that raised us from the stone age the first time around. It is a phenomenon known as cumulative cultural evolution. However, this time, there would be some memory of the past that we could benefit from so our progress would be faster. Humans would eventually ‘rediscover’ farming, we would form into towns and cities and slowly recover the technologies of the past.


What post-apocalyptic conditions or challenges might lead to humans evolving into a new species?

The only scenario that would lead to this is if the apocalyptic conditions on Earth were different enough that surviving humans needed to adapt in fundamental ways in order to flourish in the new environment.

For example, imagine the post-apocalyptic environment has high levels of some poisons or radioactivity, or contains highly virulent pathogens. Surviving humans would be those who had innate resistance.

We are already seeing from the Ebola outbreak in Western Africa that some people seem to be resistant to that virus. Offspring of these people could survive a global Ebola pandemic and then their offspring could adapt further. If this went on long enough, and it involved more than just a single feature of immunity, the new humans might eventually become a different species from the old humans.


What characteristics in particular might humans need to evolve in order to thrive in post-apocalyptic world?

This, of course, depends upon the nature of the apocalypse. Humans might need to acquire new forms of disease resistance, protection against the destructive effects of radioactivity, an ability to remain healthy without strong sunlight, and so on.

Some humans will just by chance have genetic varieties that grant them some advantages over others in these conditions, and they will be the survivors and the procreators of the next generations.


Why were animals like crocodiles and alligators resilient enough to survive mass-extinction and still thrive today?

Many small ancestral mammals, and some birds, managed to survive the K-T extinction along with alligators and crocodiles. These animals probably survived because they were able to escape the heat that this meteor strike generated. Their escape mechanisms would have included taking to the water or living in small burrows or holes.


Many of the animals that recovered from the K-T event were marine species—would humans have an evolutionary advantage if they evolved aquatic properties like gills, fins or scales?

Not necessarily. The main problem was heat and then finding food. There was plenty of oxygen still left in the atmosphere. Small mammals would have had advantages of being able to take to the water without having to breathe underwater.  Humans were not around then, and nowadays there is no pressure for humans to evolve gills.


Where on Earth might humans migrate to in order to survive or evolve into an apocalypse-surviving species?

Again, this depends upon the nature of the apocalypse.  If it is a pandemic virus, the best strategy is to get away from other humans. If it is radioactivity, we should get away from the source, perhaps by living underground or in caves. High altitudes might be helpful if the events are low-level.


Is there enough time left on Earth for another species of human-level intelligence to evolve and thrive?

It is unlikely that this could happen from scratch because that species would have to encounter us, and we would probably drive it to extinction long before it became a threat. But if for some reason we were wiped out, it is possible that another intelligent species could evolve—we know this because it has happened at least once.

Some people think that advanced AI might play this role. I think this is unlikely unless AI acquires the ability not just to think like us but to self-replicate. Then, the science-fiction narrative is that they might ‘rebel’ and make life difficult for us. But even this does not mean extinction, and the AI machines would need to have evolved ways of acquiring energy and making the technology they run on. Essentially they would have to become self-replicating entities like us. This is highly unlikely.


If Earth becomes uninhabitable during the lifespan of the human race, how might we evolve in order to survive long-term on another planet?

If this happened we would not be able to adapt quickly enough to survive on another planet. As far as we know other planets’ environments are so different from ours that we could not survive.

Our only hope would be that we had enough technology both to get us to another planet and for us to be able to survive there using that technology. This is unlikely unless we start planning for it now, and could be seen as one reason to support space exploration programs.


Thanks, Mark!