Covid-19 just part of Darwin’s dangerous idea…

Some years back, the vagaries of cheap air travel and the capriciousness of meetings schedules conspired to place me in central London with a few hours to spare.  So I took that rare opportunity to visit the Gothic cathedral that is the Natural History Museum (NHM) to see a Charles Darwin exhibition.   In my youth, pathetic in the eyes of my peers, Darwin was my hero; his simple, powerful idea excited me sufficiently to make studying science a joy rather than a chore, and I continued to learn over the years.  I have had excellent guides in the likes of Richard Dawkins, Daniel Dennett and Steve Jones.  The more we test Darwin’s theory of natural selection as the engine for evolution of the species the more we are compelled to accept that we humans, like all life, have evolved and, more importantly, are still developing.

Why Darwin’s theory elicits such popular resistance, despite our inability to disprove it, is not down merely to religious belief instead it seems people just don’t like the idea that they evolved from apes; such vanity could only be human.

In essence, evolution is; variation, inheritance, selection by the environment and, off course, time.  For humans, the process needs plenty of time.  For a species where individuals live over 40 years, time is the reason we fail to see evolution in action.  Yet this is not so for microbes, including the SARs-CoV-2 virus that is currently causing us such problems.  New viral types appear daily.   Problems with Covid-19, but also for MRSA and Clostridium dif. and our worries about other pandemics such as avian flu are really evolution in action, proof of the great man’s big idea.

As a species, humans have been successful through the use of intellect in fighting infection in practical ways, but in general, these living agents (and semi-living agents where a virus is concerned) prove more tenacious than we would like.  Once it gets started, life is hard to kill, and this is the secret of evolution.

Another aspect of evolution I find fascinating is co-evolution.  To often we are fooled into thinking that two species were made for each other when in fact, and over geological time, this perfect fit has just come about by means of a wasteful process; the honey bee that perfectly fits the flower, the bat with the ten-inch tongue that neatly reaches the bottom of the anthill and a virus that merely hitches a lift in humans to get it from Wuhan to New York.

Interestingly, pandemics have been the pressure for humans to co-evolve.  Sickle-cell anaemia and thalassaemias are diseases that are the result of genetic attempts to out-wit malarial infection, and Tay-Sachs Disease is a similar process in surviving TB infection.   The proposition put forward by Steve Jones in his book The Language of the Genes that HIV existed for many years in the human population in East Africa I find particularly intriguing.   The community in this corner of Africa were generally monogamous and the virus needed to keep a host alive long enough until he or she had a second sexual contact.    Only with sexual excess – African truck drives away from home or promiscuous gay men – came the opportunity to infect multiple partners over a shorter period, and this seems to have been the spur for the virus to evolve into a more virulent and deadly form.  What will we learn about the SARS-Cov-2 as it evolved from a life in bats, into pangolins and then into humans?  If it turns out to be wet markets, they need to close down urgently.

The biologist Theodosius Dobzhanskyin the 1970s stated that “Nothing in biology makes any sense other than in light of evolution”.  The more we look, the more we find that Darwin was right.   Yet an increasing number of educated people, particularly in the US, are unwilling to accept the science and for me, this is hugely disappointing.    As I left the NHM, I thought of the irony of housing Darwin’s exhibition in a building that looks so much like a religious institution.

Photo by aitoff is licensed under CC BY-NC-SA