The crisis of Coronavirus and the threat that pandemics pose to the human species has made me think about whether Homo sapiens, modern humans, will ever become extinct. Of course, the likely answer, if there is no time limit, is ‘yes, in the long term’, as science tells us, all species die out: the fossil evidence suggests that 99. 9% of species on earth have become extinct.
Of course, we all know about the dinosaurs and how probably, about 66 million years ago, because of the impact of a massive comet or asteroid 10 to 15 km (6 to 9 mi) wide, they became extinct as the existing global environment had been destroyed.
However, what about our own species? Early Homo species, which we know about, have disappeared, including Homo habilis, Homo erectus, Denisovans and the better known Neanderthals, who lived in Eurasia until about 40,000 years ago. We now know the Neanderthals were able to interbreed with modern humans. Back in 2013, the first fully sequenced Neanderthal genome was revealed and the present evidence shows that all non-Africans of the human population are made up of about 1.5 to 2.1 per cent Neanderthal DNA - the old derogatory joke “ I know quite a few people with a lot more Neanderthal in them”, indicating low intelligence and brutish behaviour, no longer works. Recent discoveries, like a piece of 50,000-year-old string - the oldest yet discovered - found in a cave in France, has cast doubt on the belief that Neanderthals were cognitively inferior or less intelligent than modern humans.
What drove the Neanderthals to extinction is still a mystery, There are many theories, like violent extermination by modern humans, climate change and so on. One idea, however, is particularly apposite in this time of Coronavirus and that is that Homo sapiens exposed the Neanderthals to deadly parasites and pathogens, which they were unable to resist. Modern humans came from Africa and it might have been that the European Neanderthals had limited immunity to new diseases imported by these incomers. We know that it is relatively easy for pathogens to leap between two similar species (we have also learnt that in some cases pathogens, viruses, can transfer from one species to another as in the case of Covid-19).
Homo sapiens must have lived in close proximity to achieve the interbreeding that took place and our species could have provided a pool of individuals capable of infecting the Neanderthals and creating an epidemic that completely decimated them, eventually driving Neanderthals into extinction. A relatively modern comparison would be how the European colonists brought diseases that were deadly to the indigenous populations of the Americas: for example, in the 16th century the Spanish brought smallpox to Mexico and it is estimated that half the Aztec population died of the disease.
Human beings down the centuries have often displayed an apocalyptic tendency (this deserves a future blog) - meaning there is a fear that the end of ‘the world is nigh’ to use an old Biblical phrase. If we put aside any supernatural ending for our species, there are plenty of more scientific explanations as to how we could become extinct: favourites would be an asteroid strike, like the one that did for the dinosaurs, or climate change and the destruction of the environment which is already having a negative impact on human life, and other self-inflicted armageddons like, nuclear war, ‘singularity’ and the take-over by AI (‘the machines’) and extermination of the inferior humans, or it could be a pandemic - a deadly pathogen which we cannot resist, and that takes me back to my thoughts at the beginning of this piece.
The good news is that we humans are an immensely adaptive species, hence our amazing success in reproducing all over the globe and in such numbers that we are difficult to eradicate. The bad news is, all the evidence suggests we will become extinct, we just don’t know when!
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