Sometimes, getting better means losing traits

Every day, in every way, I’m getting
better and better and better.

Well, maybe. But what if the most efficient way to survive is to get worse, letting someone else take care of the better? What if selection works in both directions, gaining genes and losing genes, adding what you need and deleting what you can let others do for you?

In the microbiological world, there is evidence that natural selection does, in fact, work in both directions. While some organisms add genes and gain advantageous traits, other organisms give up genes that they no longer need.

A team at the University of Tennessee at Knoxville interprets the behaviour of the most prolific photosynthetic organism on Earth, Prochlorococcus. It turns out that because Prochlorococcus is very sensitive to substances like hydrogen peroxide, it is hard to grow in the lab. It can’t handle the toxicity.

If Prochlorococcus is so delicate, how did it proliferate so widely? When other species in its neighbourhood developed the ability to break down hydrogen peroxide, Prochlorococcus switched off its own defense systems, allowing it to devote itself to other tasks, like ramping up its reproductive capability. Prochlorococcus flourished thanks to living in harmony with other species that offered it specific protections. There was a time when Prochlorococcus performed its own toxic cleanup, but its neighbours do that job for it now, and it has lost the necessary skills.

Eric Zinser, the microbiologist who led the UKN research, acknowledges that so far the hard evidence for “natural deselection” is limited to the microbiological world, but he thinks that the process could operate in larger, free-living organisms, as well.

I’m interested in the human social parallels. While it can be misleading to interpret social dynamics as if they were evolutionary processes, there are attractive similarities.

In the early pioneer days in the American West, everyone was a farmer, a herder, and a hunter. Everyone was a cabin builder, a well digger, and a cabinetmaker. If you didn’t farm it, tend it, or make it, you didn’t have it. Soon, of course, as the population increased, specialization changed things. You didn’t have to grow corn if your neighbour did and would sell some to you, or trade it for the meat from your herd of cattle. And so on, until a few big corporate farms now supply all of our corn, and most of us have lost the skills necessary to successful farming.

On a larger scale, there are many smaller or weaker countries that “piggy-back” on their more powerful neighbours. There are modern economic examples. For decades after WWII, Japan restricted its domestic imports while selling abroad in huge volumes. By letting other countries absorb the trade deficit, Japan’s economy flourished. In a similar way, China today restricts its currency while it benefits from the floating currencies of its trading partners.

And in military spending, Canada and other middle powers continue to rely for defense on the United States, which provides the nuclear shield that keeps these other countries from spending enormous amounts on their own defense. And so on.

The most encouraging notion that comes to me out of this small news report is even more of a stretch.

If it’s true that in the right circumstances species can thrive not just by acquiring traits but by shedding them, can we think of any human traits that we’d benefit from losing? That is, are there ways that our evolution could be advanced by going backwards?

If the evolutionary psychologists are right that human nature is the outcome of positive selection during the hundreds of thousands of years that we were savannah dwellers, then our environment selected characteristics appropriate to that time and place.

We don’t live in that time or place any longer, but we’re stuck with not just a craving for sugar or a dread of snakes. We also retain the aggression and clannishness, the fear of strangers and compulsion to acquire and store resources, the leopard-in-the-tree bias for god-creating, that are their legacies.

Maybe, if our civilization survives our heritage traits, our descendants will be fortunate to have deselected the violence and ignorance that threaten us today.

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One thought on “Sometimes, getting better means losing traits

  1. Deselection in humans is usually seen as a negative leading to the large headed super brains with puny bodies attached in a science fiction future. Nice to think of possible positive effects and Pinker’s Better Angels of Our Nature will prevail.

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