The Secret of Evolution

While out walking the other day I saw a seed pod that had fallen from the chestnut tree overhead onto the sidewalk, had been crushed, and dried out. And that got me thinking: whatever new and useful mutations that seed might have contained were now wasted, dismissed by evolution in a random event, by sheer bad luck, for failure of germination.

And that seed represents all life everywhere in the universe. To paraphrase the Bible, some seed falls on good ground and thrives, some on barren ground and dies. To paraphrase the basic tenet of evolution: that which thrives and breeds, survives and directs the future; that which shrivels and dies, does not. The secret of evolution is that a thousand, a hundred thousand, maybe a million seeds from that one tree over its lifetime will fall to the ground; some might get random mutations, and others might not. But for most of them, it does not matter, because only a few of them survive and grow into another tall tree to continue the cycle. A million seeds, random mutation, random extinction, only one or two successes to shape the future.

The secret of evolution is that events indeed are random, but the direction is still purposeful: that which thrives, survives. Period, full stop. Existence rewards success with more existence, and improvement is its own reward, judged solely by the bearer’s ability to contribute to thriving and surviving.

From this we get not just bacterial mats, corals, mosses, and chestnut trees. We get butterflies, robins, hawks, and human beings. And on the way to those ends we get crayfish, dormice, and dinosaurs. And those are not the end of evolution at all, because humans, so far, have created the steam engine, internal combustion, radios, computers, and the first whiffs of artificial intelligence. We have cracked the code of DNA and are learning to repair our own selves and heal the world around us. With more to come. The advances come randomly, but the effect is purposeful.

This is something that the followers of creationism or “intelligent design” do not understand. They look at the structure of, say, the human eyeball, a self-adjusting camera built out of collagen, proteins, and colloids, and marvel at its complexity and its purposeful functioning. They believe that for something to have purpose, it must have been designed to achieve that end. Some greater intelligence must have thought out the structure in advance and then placed each fiber, each protein, just so as to create the effect of a working eyeball. They don’t see how random chance could have achieved this.

But two things, perhaps three, get in the way of their thinking. First, they don’t understand how long evolution has been working on eyeballs. The first eyes—or light-sensing nerve endings—date back to the Cambrian explosion, when single-celled life began forming collective beings with differentiated cells, about 540 million years ago. Since that time, eyes diverged between the compound, crystalline structures of the insects and single-focus, globular structures of the fish, which successively became the amphibians, reptiles, and the mammals that followed them. Half a billion years is a long time to experiment with light-gathering techniques.

And the core command of evolution governs the process. Mutations in the genes for eyes that improve light gathering, detection, and discrimination in the environment into which the individual is born will help it thrive and breed. Mutations which damage or deteriorate those functions keep it from thriving and breeding.¹

When I was working at the biotech company, I learned about a technique called “directed evolution.” The scientists there were working on improving the function of their Thermus aquaticus (that is, hot water bacteria) polymerase, the molecule that zips along a single strand of DNA during replication and adds complementary bases (that is, A’s to T’s, C’s to G’s, and vice versa). Now, as one scientist explained to me, she had no idea how to improve the polymerase. She couldn’t design a better one, because we don’t really understand what drives it in the first place. But she had the DNA code for the polymerase molecule they were working with.

In the process of directed evolution, she copied the polymerase DNA a dozen or a hundred times. Then she made a random mutation somewhere in each of the samples. She used the altered samples to make new copies of the polymerase protein and tested those mutated proteins for function. Those that worked better than the wild-type protein that the company was currently using, she kept; those that worked no better or worked worked not as well, she discarded. From each of the slightly improved samples, she made a dozen or a hundred more copies and gave each of them another random mutation. Repeat and repeat: mutate, grow new proteins, test them; keep the successes and discard the failures—even if one of the samples that worked better in the first batch worked no better now or showed a slight decrease in function. Keep up the process a couple of dozen more times, and eventually she would get a polymerase that reliably worked better than the wild type.

The point is, this scientist did not have to design the DNA sequence that world work better. She did not have to plan out the mutations that would achieve it. She only had to arrange for sequential additions of random mutations and test each one under the rule that anything that succeeds survives, and anything that fails disappears. The test is fitness for a specific purpose. And sometimes it takes many iterations of testing and discarding to change the future.

The second thing that gets in the way of looking at evolution vs. intelligent design is that the followers of the latter look around and see the world in fixed form. They think horses have their present shape and function because there is something perfect and eternal about “horsiness,” which was Plato’s idea of an eternal prototype existing somewhere out in the cosmos. The horse eats grass and has a compact foot with a single, rounded hoof because it runs over solid ground, which that hoof can easily navigate, and that ground happened to be covered with rich grass. But early horses had toes, just like most tetrapod mammals, and only adapted to standing on a single, developed “finger” with a rounded “fingernail” because it found itself in a suitable environment over preceding generations. And the same with the horse eating the available grass as opposed to leaves or berries or other foods.

Life is change. That which adapts through mutation and selection of successful traits, survives and directs the future; that which fails to adapt, dies. Humans are also in a state of change. We will evolve eventually, especially if our environment changes slowly enough for random mutation to do its work.² Or we might, through our own enhanced brains and understanding, take over our germline evolution and create new variants, perhaps even a new species, with a form and function, skills and traits, that our knowledge and foresight—or perhaps our ideologies—decide would be better.

But even then, we won’t become intelligent, designing gods, but more like random selectors, rolling dice and hoping for a better outcome. And in that case, a lot of our seeds will fall on barren ground.

1. Of course, the process is a bit more subtle and complex than that. Some mutations have no obvious immediate effect. For example, DNA’s three-base reading frame is structured—by random selection, of course—so that changing the third base pair (dubbed “the wobble”) does not always change the amino acid which the reading frame codes for. This has the effect of slowing the rate of effective mutations.
    And then, not every amino acid compiled in a particular protein has a direct and immediate effect on that protein’s function. So some mutations wait in the cell’s DNA, dormant and unchanging, perhaps over generations, for the chance to meet up with another subtle mutation that may then, working together, affect form or function.
    And finally, mutations that occur in the somatic cells—those out in the body of the organism—never get carried forward. It is only changes in the germline cells—those that are segregated early in the testes to become sperm and the ovaries to become eggs—that go on to affect future generations. But once an egg or sperm carries a mutation—and only if it happens to join with its opposite number to actually create new life—it propagates that mutation to all the cells in the new body. And some of those—perhaps in the eye tissue of our example—will either improve or damage the tissue’s function.

2. And if not, then study the dinosaurs.

Boredom

I was making my dog’s breakfast the other morning—and yes, she eats twice a day, morning and evening, same meal—and noted that after all these years, she’s still excited about it. She noses the bag of kibble and jumps up on her hind legs as I take out the can of soft food to put on top of the kibble. Always the same eagerness to get what is exactly the same meal she has been eating, morning and evening, for the past seven years. Maybe it’s hunger pangs, but she gets fed regularly enough that she shouldn’t be bothered by them. It’s just that, with the same meal twice a day, you think she would get bored with it, become picky, sometimes turn her nose up.

And she’s still excited to go out for her walks every day, the same dancing and tail wagging, the same pulling on the leash. We walk four, sometimes five, times each day, almost always the same route, always the same smells from other dogs in the condo complex. The excitement may have something to do with relief of her biological processes, but she doesn’t always let go as soon as she reaches open ground. So it’s not just urgency of bladder and bowel. She is actually excited to be seeing the wide world, again, and again, and again.

Why doesn’t a dog get bored with its existence? How does it keep enthusiasm for the same routine, day in and day out, that would drive a human being to distraction? I think the answer is that the dog has no—or very limited—imagination. It cannot think of something different that it would like to do. In its existential being, a dog is experiencing everything—short of pain and maltreatment—as the way things should be, the good life, oh boy!

My belief is that dogs and other animals have brains, sensations, understanding, and emotions not unlike us humans. What they lack is an essential sense of self. They do not have the capacity to see themselves in what they do and feel.¹ They can certainly register a pain such as hunger, or a pleasure like the effects of being talked to and stroked. They feel loss when separated from their pack members—in this case, me when I leave the apartment—or other social structure. But they don’t have the introspection to place themselves in an existential situation (“Now I am alone”) or the imagination to create an alternate reality which they might emotionally inhabit (“I wish my master, guardian, pack leader were here to comfort me”).

To become bored with your current existence requires that you have the introspection to perceive it as something separate from your immediate feelings and the imagination to create an alternate existence, however fanciful, that you might actually occupy—or simply think is possible.

To be bored with your breakfast, you have to imagine eating something else that you’d like better. To be bored with your daily walk, you have to imagine someplace else you’d like to go. All this raises the interesting question of whether the dog would become bored with her breakfast if I fed her a varied diet, sometimes kibble and canned soft food—although I do vary the labeled flavors and consistencies of both when I shop for her—sometimes a bowl of my own daily oatmeal with milk, or a cut-up steak, or anything else that would not harm her? And note that bits of human food fed by hand or licked out of a used bowl have great “status” with dogs, indicating that they are being treated more like one of the family. So then, would she yawn and turn away from the kibble and soft food, knowing that she might—in her early morning imagination—get something better?

Would she become bored with the same walk around the property and around the block if sometimes we stepped out of the door to drive to the park, sometimes went to the woods or the beach, where there were new and exciting smells? Dogs love to find a dead seagull because of, you know, the opportunity to roll in it.

I don’t know, but I doubt it. I occasionally give her hand-fed bits of nuts, potato chips, and popcorn, or let her lick my cereal bowl. So she has altered foods in her memory, but she’s still excited by the old kibble-and-canned. And she knows about going to the park and still pulls on her leash to walk out back among the familiar smells.

Dogs do still get bored. When I am at my computer, the dog settles down on a cushion under the desk. When I have to go out, she retreats to the bed or to a sunny patch just inside the window. And there she sleeps or at least shuts her eyes and pretends to sleep. I know that I am boring the dog because she is not getting enough stimulating company to do anything else but sleep. But there again, she doesn’t fret, pace, and grumble about my not paying enough attention to her. She doesn’t come out from under the desk or out of the bedrooms until her biological clock says it’s time for the afternoon walk and feed. And if I get up from work for something, she often—but not always—follows me to see if there’s something interesting to do. But I doubt she has much idea about what that might be.

A dog’s life might look to a human like an extended prison stay, with the same slop served morning and evening, limited bathroom breaks, and not much to do for the rest of the day until the warden says it’s time for exercise. But the dog seems happy enough and leaps at the chance.

1. This apparently is not true for all animals. Dolphins, certain whales, perhaps most primates, and possibly elephants appear to have a sense of themselves. They can recognize themselves in a mirror, whereas a dog or cat on encountering a mirror—if it notices the reflective capability at all—will think it’s seeing another dog or cat and react accordingly. But put a mirror in a dolphin’s pool, then strap a funny hat on the dolphin’s head, and it will immediately go to the mirror to see what you have done. It knows that what it is seeing in the mirror relates to itself, and so it has a self-image and perception of itself as a separate and distinct being.