Why You Are Not a Prairie Dog: More Insights from Loren Eiseley

I have recently been reading essays by Loren Eiseley, a paleontologist of the middle twentieth century. His books, such as The Firmament of Time and The Immense Journey, were considered epics of popular science writing at the time they were published. Many of his essays are very well-written, and I recommend him to any of you who like classic nature writing.

One of his essays, The Slit, is about a time in which he went down into a cavern and dug out a mammal skull from shortly after the extinction of the dinosaurs. Primates, the order to which humans and other apes belong, started to diversify right after the dinosaurs became extinct. One of the directions that they diversified was into arboreal forms, living in the trees. And that is where most of them still are, except for baboons and people. Another direction was to live by burrowing in the ground out in the newly-spreading grasslands. These primates eventually became extinct. Why? It was probably because of another order of mammals that was evolving and diversifying at the same time: rodents, which includes prairie dogs and ground squirrels. [Here is a photo I took of a prairie dog in the Badlands of South Dakota in 2000.]

Very early in the Cenozoic Era, it was not clear which direction mammalian evolution might take. Out in open prairies, both primates and rodents diversified. But the rodents were more successful, driving the burrowing primates to extinction. Had things ended up just slightly differently, primates might have been primarily burrowing animals, rather than leaping around in trees. And humans might not have evolved.

Another insight I got from reading Eiseley was a possible contributing factor to human intelligence. Our big brains require a lot of oxygen, therefore a lot of blood vessels. Why did our lineage, starting with the amphibians, have such well-oxygenated brains? The answer might be that amphibians evolved not just in shallow water, not just in shallow fresh water, but in shallow fresh anoxic water, so that extra blood vessels were required to keep even their small brains alive. It was this extra vascularization that made the evolution of intelligent terrestrial vertebrates possible.

To me, this was an excellent example of how the slightest change in the course of events can make a huge difference in the evolutionary outcome.

Are We the Inevitable Products of Mathematical Equations?

I have just finished reading Martin Nowak’s Super Cooperators, a book written with Roger Highfield. Nowak is a biomathematician at Harvard. He has spent a career designing mathematical models that demonstrate the conditions under which altruism can evolve. Altruism is when one animal is nice to another animal of the same species.

Nowak’s view of the world resonates with my spirit. He sees the natural world as full of cooperation. Cooperation is at least as important as the “survival of the fittest,” which Darwinism is often portrayed to be. I find his viewpoint inspiring just like the viewpoint of Lynn Margulis (whom Nowak hardly mentions). The fact that Nowak is a fellow devotee of the music of Gustav Mahler doesn’t hurt any either.

And some important results have emerged from Nowak’s mathematical models. I cannot summarize all of them, but one that I remember is the following. In simple, direct interactions, when a cooperator and a defector come in contact, the defector always wins. That is, the cooperator becomes a sucker for offering help that is not reciprocated. In large populations in which all the animals are equally likely to come in contact, altruism doesn’t have a chance. But in populations in which small groups can form, where animals can choose their friends, so to speak, altruistic groups can emerge. And when they do, they can beat out the pathetic defectors every time, at least temporarily. This is particularly the case in animal societies where the animals know the reputations of other animals, which is something they can do within small groups. This is, in fact, probably the most important way in which altruism evolved. It is an example of multi-level selection: selection among groups within a larger population.

However, in one sense, I consider Nowak’s work to be unrealistic. He begins the book by expressing his feeling that all of truth can be expressed precisely by mathematics. Toward the end of the book, he claims that his equations would be true anywhere in the universe. He admits that his conclusions are not too different from beliefs, such as the Golden Rule, found in traditional religions. But he still thinks he has made a monumental universal discovery. “Now, for the first time, aspects of these powerful ideas [from religion] have been quantified in experiments, captured in equations, and enshrined in science.” He seems to mean that ideas such as the Golden Rule are really true for the first time in the history of the universe as a result of his mathematical simulations.

Nowak’s mathematical approach is unrealistic because it omits all historical contingency. In Nowak’s models, animals are cooperators or defectors for logical reasons. So maybe his equations would work reliably on the planet Vulcan. But they cannot be relied upon for human behavior. The equations mirror many, but not all, aspects of human behavior. The primary historical contingency is religion. The memes of religion have parasitized the human mind to such an extent that, throughout human history, many people have considered it a religious duty, absent any benefit, and more important than life itself, to bring death and destruction to others. Nowak’s models do not include the thirst for evil that is so common in human motivation, in which loss is reward because it ensures eternal life in a heaven.