Natural selection simplified


Antibiotic resistance - natural selectionI was startled by the simplicity of the forumla. Stephen Jay Gould, the late eminent paleontologist, biologist and historian of science, summed up Darwin’s basic theory of natural selection so eloquently and so succinctly that it rocked me back on my heels. It was something even a diehard creationist could understand (assuming he or she wanted to try…)

First there are three basic facts Gould states about life and living creatures:

  1. All organisms produce more offspring than can possibly survive;
  2. All organisms within a species vary from one another;
  3. At least some of these variations will be inherited by offspring.

From these three, simple facts – easily proven by observation, research and analysis – Gould says the principles of natural selection, as Darwin postulated in 1859, can be inferred. These are:

  1. Since only some offspring will survive, on average these survivors will have those variations that are generally better adapted to survival in changing environments;
  2. Those offspring will inherit the favourable variations of their parents;
  3. Organisms of the next generation will be better adapted to local environments.

Simple, eh? I thought so, too. Next year will mark 160 years since Darwin’s On the Origin of Species was first published. I already have a bottle of wine aging for the celebration.

I came across this elegant description some years back, while reading Evolution: The Triumph of an Idea, by Carl Zimmer (Harper Collins, New York, 2001). The book is the companion to the PBS series on evolution. Gould wrote the introduction. I have yet to see the series (we don’t subscribe to TV) , but I enjoyed the 364-page book. It’s one of many such titles in my library.

Gould sums up Darwin’s ideas in such a simple manner it is like a bright light illuminating the dark corners of our world. The book is itself a rich text on the science involved, and also about Darwin and the many people involved in the theory’s development in the last 150 years. It’s about the social impact his ideas have had, and about how they tie in with what else we know about the universe. Connected, all things are connected.

Wikipedia makes the process a little more complex (naturally) but nonetheless understandable:

  1. All living things have such fertility that their population size could increase rapidly forever.
  2. Actually, the size of populations does not increase to this extent. Mostly, numbers remain about the same.
  3. Food and other resources are limited. So, there is competition for food and resources.
  4. No two individuals are alike. Therefore, they do not have the same chance to live and reproduce.
  5. Much of this variation is inherited. The parents pass the traits to the children through their genes.
  6. The next generation comes from those that survive and reproduce. The elimination is caused by the relative fit between the individuals and the environment they live in. After many generations, the population has more helpful genetic differences, and fewer harmful ones. Natural selection is really a process of elimination.

There is an underlying human need to impart order and meaning to existence, be it through religion, laws, politics or science. While sometimes these areas conflict, it’s impossible to argue successfully against the evidence that Darwin and a subsequent century-and-a-half of his successors have discovered and presented. Evolution is a fact.

Yes, I know, that hasn’t stopped the creationists from fighting it, but their arguments are like someone standing in the rain claiming it’s sunny out. No matter how many pseudo-arks the hubristic Ken Ham builds, nothing can erase the evidence left in the fossil record.

Facts are facts; opinions, religious or otherwise, are just that. They have all the value of the oxygen used to express them, and nothing more. I’m sorry but no one has to respect another’s opinion if it disagrees with evidence and fact. Opinion doesn’t have to be taught alongside science, either.

I started reading Darwin when I was 12, and continue to read him even today* (a recent book purchase was a paperback about how to argue with creationists through facts and science – delightful reading) but in all that time I have never read as short but direct and clear an explanation that I could use to explain Darwin’s ideas to others.

Gould points out that one can only make sense of the “quirks and imperfections” in modern organisms by appreciating them as holdovers from an ancestral state; that is, changes that were inherited but are no longer relevant to the current environment. The appendix comes to mind. Most of our hair, too, no longer serves its original biological purpose. And there are others, but none of them disprove evolution any more than a warm day in February or a cold day in July disproves climate change. But I digress…

Gould also believed Darwin’s discovery was the single most important revolution in scientific thought, in that it “upset our previous comforts and certainties” in ways no other discovery did. More than, for example, Copernicus’ discovery that the Earth orbited the Sun, not the other way around. That’s a bold statement, but others agree. Michael Dixon, director of Britain’s Natural History Museum, recently wrote in The Guardian:

Darwin’s theory of evolution not only underpins all biological science, it has an immense predictive power. From understanding the emergence of antibiotic-resistant organisms, to the ways in which different species might respond to global warming – emerging as new pests or sustainable sources of food – human health and prosperity will depend on decisions informed by evolutionary evidence.

Yet for all its deep impact on our psyche and our sciences, evolution remains perhaps the most misunderstood and most controversial of the great ideas. Because of the misunderstanding, and the populist anti-science/anti-intellectual cultural climate in some countries (hint: the USA) it is not believed in by a large segment of the population. That’s not unlike having the majority of the population believe in a flat earth, or that the Earth is the centre of the universe.

Yes, I know: wingnuts abound who believe in both. (Sigh: the internet…)

A Pew Research study done in early 2017 found that,

…33% of all Americans) express the belief that humans and other living things evolved solely due to natural processes. A quarter of U.S. adults (25%) say evolution was guided by a supreme being. The same survey found that 34% of Americans reject evolution entirely, saying humans and other living things have existed in their present form since the beginning of time.

Sad and frightening that the percentage of those who reject evolution is so high, but given the bustling theocracy and the growth in anti-science, anti-intellectual evangelism in the USA, not surprising. As the study found, “…a solid majority (57%) of evangelicals say humans and other living things have always existed in their present form.” Say no more.

A more recent survey from Research Co. found that,

… two thirds of Canadians (66%) say that human beings “definitely” or “probably” developed from less advanced forms of life over millions of years. Conversely, one-in-five Canadians (21%) think that God “definitely” or “probably” created human beings in their present form within the last 10,000 years.

Which is confounded somewhat by the statement that “Across the country, almost half of respondents (46%) believe creationism should not be taught in schools, while more than a third (38%) think it should be.” If they don’t believe in creationism, why do they believe should it be taught in schools? (Canadians: don’t gloat too much about our intellectual superiority over Americans. A 2017 survey found 43% of Canadians believe scientific findings are a matter of opinion. Sigh… so much for our alleged better education: four in ten Canadians don’t understand the scientific method and one in five are creationists…)

CartoonTeaching creationism alongside or even instead of evolution is akin to teaching the flat earth nonsense as an alternative to global geography. Or teaching astrology as an alternative to astronomy. Or giving the Nobel Prize in science to David Wolfe Avacado and Gwenyth Paltrow!

While other scientific discoveries may be equally or more important – the laws of gravity, special relativity, motion, DNA, the Big Bang, the age of the Earth, quantum physics, and many more – few if any have had the social seismic effects Darwin’s had. Or stirred the ignorati to such fervour to counter it.**

Findings like Darwin presented provide ‘cold comfort’ – they give us no ethical, moral or spiritual clawholds onto which we can cling. They are spiritually neutral; it is up to us to fold our faith around them in such a way that faith make sense in light of the cold truths of science, not the other way around. If, that is, we have such weak faith that needs buttressing (I, for one, don’t).**

But for some even that neutrality is frightening: evolution divorces humankind from the cozy hierarchy of animal-human-god and instead places us in the tree of life on just another branch, sharing but not dominating, linked and dependent on the rest of the tree. We’re all just animals, and not even very special ones at that. That means such brutal activities as trophy hunting can’t be justified by our divinely-ordained dominance. They prove to be merely violent, nasty, immoral and unethical.

Gould himself once wrote, “Humans are not the end result of predictable evolutionary progress, but rather a fortuitous cosmic afterthought, a tiny little twig on the enormously arborescent bush of life, which if replanted from seed, would almost surely not grow this twig again.” Pretty humbling, if you think about it.

That’s a difficult step for many religious people to make. Having removed the human from the throne of divine preference, we are forced to come to grips with our animal nature, not as separate from, but part of the web of life. It means that other things around us – like climate change – are our responsibility, not the result of a poke by divine finger. 

But perhaps that liberates us, as well. Freed of the restrictions – and constrictions – imposed upon us by an anthropocentric mythology and self-aggrandizing religion, we are able to understand and marvel at our actual place in the universe: how truly miraculous (in the secular sense) all life is. And how marvellous free will and responsibility are. Assuming, of course, people are willing to shoulder the burden of responsibility.

If we embrace evolution as fact, we might be able to better appreciate our role in the web of nature, not see ourselves as an animal set apart and above it. When that happens, we will be better able to act as environmentally-aware stewards of the world, not its anointed masters. And that means we need to take care of, not just take dominion over, the world.

Yeah, right. Like that sort of awareness is likely to happen, especially among the theocrats or Trumpists south of the border. Still, I live in hope that one day the percentage of people who believe in creationism will be in the lower single digits.


* Until I ran headfirst into the insurmountable wall of high-school Latin, I intended to become a paleontologist (Latin was then a required subject for many sciences and still taught in high school, along with penmanship). That diminished my career prospects but not my enthusiasm or my reading. However, reading Darwin alone, or even reading evolutionists like Dawkins and Gould alone is not as powerful for developing understanding in evolutionary theory as reading in conjunction with other disciplines such as paleontology, biology, anthropology, botany and virology.

** From Gould: The Evolution of Life on Earth, Scientific American, 1994:

Sigmund Freud often remarked that great revolutions in the history of science have but one common, and ironic, feature: they knock human arrogance off one pedestal after another of our previous conviction about our own self-importance. In Freud’s three examples, Copernicus moved our home from center to periphery, Darwin then relegated us to “descent from an animal world” and, finally (in one of the least modest statements of intellectual history), Freud himself discovered the unconscious and exploded the myth of a fully rational mind. In this wise and crucial sense, the Darwinian revolution remains woefully incomplete because, even though thinking humanity accepts the fact of evolution, most of us are still unwilling to abandon the comforting view that evolution means (or at least embodies a central principle of) progress defined to render the appearance of something like human consciousness either virtually inevitable or at least predictable.

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