Monday, 19 September 2016

Evolution, the future and us: any evidence?

Walking through Cleveland Park and Pitshanger Park to get my 10,000 paces in today, I see many other walkers, joggers and cyclists out and about, as well as people using the exercise machines and playing tennis. Great stuff! No doubt most of these good people eat a healthy, balanced diet and take care of themselves.

But what of the rest? The ones driving themselves a few hundred yards to the fast-food takeaway, fag in hand? The ones who are nowhere near their five portions of five fruit-and-veg a day, or walking 5 miles/8km a day? What will happen to their children, grandchildren and great-grandchildren?

Is there any chance that homo sapiens as a species will branch into two distinct sub-species?

Before I start to ponder the future, I shall ponder the evolutionary recent past. I chanced upon an interesting article the other day, about wisdom teeth and human evolution. In 2004, scientists discovered the MYH16 gene, which regulates the strength of our jaw muscles. You need strong jaw muscles to bite through the hide and rip the raw flesh off a freshly-killed beast, then grind it down between your molars thoroughly enough to swallow.

But once homo sapiens learnt to harness the power of fire to bring about the chemical transformation of meat, and to use flint implements to remove animals' muscle fibre from bone, so the need to tear away at a carcass and chew meat became less of a survival imperative. The jaw muscles became weaker, through a mutation in the MYH16, allowing the skull to expand in size and accommodate a larger brain; finer control of the jaw facilitated speech . This from evolutionary scientist Matan Shelomi:
"Our mouths are getting smaller and more bullet-shaped. Our teeth aren’t quite changing as fast, which is why orthodontics and wisdom teeth removal still exist … for now. More and more people are being born without wisdom teeth, or have their wisdom teeth erupt later if at all. Wisdom teeth were useful before knives and cooking, when humans would probably lose molars to chewing hard food and needed the wisdom teeth as replacements. Today, 35% of people lack wisdom teeth, although the genes involved in this are unknown so we aren’t quite sure why this is happening yet."
Now I understand why I only have one wisdom tooth (lower right), while the remaining three have failed to emerge. It is not that I lack wisdom or maturity, no - it is because I'm evolutionarily more advanced than the rest of you primates (I jest of course).

In other evolutionary indicators, however, I'm less advanced. The gene allowing humans to metabolise milk once they are no longer infants proved really useful. Most common in north-west Europe, it led to the development of dairy farming; it is one reason why the Dutch are the tallest men in the world. Now, as child I had a mild revulsion to raw milk, but could still drink it in tea or coffee until I was in my late 30s, after which intolerance set it. [I can still eat cheese, butter and yogurt]. Milky tea? Bleuugh! Lactose tolerance is found in 90% of northern Europeans, but only 10% of east Asians.

Blue eyes are another human evolutionary novelty, appearing as recently as 6,000 years ago in the Black Sea region. Conferring a 5% advantage in reproduction, blue eyes have now spread to around one-fourteenth of humanity. (Not me, setting me back a few thousand years evolutionarily speaking)

If Darwin had anything to shout about, tall, blue-eyed, lactose-tolerant, small-jawed people without wisdom teeth would be biologically fitter, meaning they'd have more offspring, driving out the short, brown-eyed, lactose-intolerant, large-jawed people equipped with a full set of 32 chompers.

Hang around for a few million years to see if this is indeed the case...

Meanwhile, back to Pitshanger Park, I'm reminded of a Sunday morning in Liverpool about ten years ago. I was on the bus from the airport to the city centre. The bus was full of boys and young men in football kit, clutching footballs, heading to the parks to play footie. The pavements were full of runners, the roads full of cyclists, cars were driving kids to karate classes - it seemed like the entire city consisted of fit, active people enjoying sport. But I knew what I didn't see that morning - the unfit part of the population lying in bed, too lazy to get up and move.

There is a clear correlation between fitness and intelligence, between having the will to live a healthy life and eating sensibly and exercising.

Now the crucial question for evolutionary biologists is - so what?

Ten years ago, a movie came out that failed to take the box office by storm, but nevertheless became a cult classic - especially in the year that Donald Trump strives to become US president. The movie is called Idiocracy - see it, do - it's wretchedly funny. The premise is as follows:
"As the 21st century began, human evolution was at a turning point. Natural selection, the process by which the strongest, the smartest, the fastest, reproduced in greater numbers than the rest, a process which had once favored the noblest traits of man, now began to favor different traits. Most science fiction of the day predicted a future that was more civilized and more intelligent. But as time went on, things seemed to be heading in the opposite direction. A dumbing down. How did this happen? Evolution does not necessarily reward intelligence. With no natural predators to thin the herd, it began to simply reward those who reproduced the most, and left the intelligent to become an endangered species."
This science-fiction satirical comedy, set 500 years in the future, presents a dystopian vision of a nation run by the dumb pandering to the dumb. Could this come to pass? Intelligent people failing to breed?

Or will intelligent, fit - and wealthy - people will seek one another out, reproduce to bring into the world children that are advantaged from birth, while a genetic underclass, unfit, unhealthy and of low intelligence, lacking the will or nous to self-improve, evolve into a separate subspecies?

Or will the children of the wealthy settle comfortably into a complacent life that brings them a reasonable existence without needing to strive - while the children of the have-nots struggle against the odds to get the better jobs in a competitive labour market shaped by globalisation, robots and algorithms?

And another question: does longevity confer any evolutionary advantage, or is the product of evolutionary selection for its own sake?

Coming to the end of this post, I'm forced to ask once again - is there a gene that determines will? That determines determination? Is it why some people seek more and more, while others are content with just enough to get by on?

Strive to understand your biology, and strive to overcome it.

I happen to believe in spiritual - as well as physical - evolution. But that's for another post.

This time two years ago:
Relief as Scots vote to remain in UK

This time three years ago:
The S2 opens all the way to Puławska

This time four years ago:

This time five years ago:
Push-pull for Mazowsze

This time six years ago:
Okęcie runway repairs are complete

This time eight years ago:
I know that painting from somewhere...

This time nine years ago:
The March of Progress, ul. Postępu

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