Category Archives: Evolutionary Biology

What is meant by “mosaic evolution” and other matters

A discussion of misconceptions in evolution … about missing links, or great chains of being, or teleology (the idea that evolution is goal-directed) has got to be the most fun you can have with your pants on. Pursuant to this, let’s sharpen and clarify our evolutionary theory mojo by considering the concept of “mosaic evolution” … what is it, and what isn’t it?

Of course, the concept of mosaic evolution, meant to clarify how evolution works, is often itself misunderstood. From Wikipedia:
Continue reading What is meant by “mosaic evolution” and other matters

NASA’s new organism, the meaning of life, and Darwin’s Second Theory

ResearchBlogging.orgIn his highly readable book, One Long Argument, Ernst Mayr breaks down the body of thought often referred to as “Darwin’s Theory” into five separate and distinct theories, the second of which being “common descent.” Darwin’s second evolutionary theory (second by Mayr’s count, not Darwin’s) is really a hypothesis that could be worded this way:

All life on earth descended from a single, original, primordial form that arose eons ago.

The evidence in favor of this hypothesis is strong, but the test of the hypothesis … the means of disproving it, which is, after all, the point of stating it to begin with … is difficult to define, but like pornography to a judge, one would know it when one sees it.
Continue reading NASA’s new organism, the meaning of life, and Darwin’s Second Theory

What is the most important human adaptation?

Human infants require more care than they should, if we form our expectations based on closely related species (apes, and more generally, Old World simian primates). It has been said that humans are born three months early. This is not accurate. It was thought that our body size predicted a 12 month gestation, and some suggested that Neanderthals would have had such, but this research conclusion has been set aside based on new analysis. But it is still true that developmentally, human children do not reach a stage of development that allows some degree of self care for a very long time compared to apes. The actual sequence of development is not directly comparable: It is not the case that after a certain amount of time humans reach a specific stage reached earlier in the lifecycle by Chimpanzees, as the differences are more complicated than that. For the present purposes, we can characterize the human condition for early development like this: Human babies are more helpless in more ways and for longer than comparable ape babies.
Continue reading What is the most important human adaptation?

Why do women shop and men hunt?

Or, when the hunting season is closed, watch teh game (the guys), or when there are no sales, admire each other’s shoes (the gals)?

This is, of course, a parody of the sociobiological, or in modern parlance, the “evolutionary psychology” argument linking behaviors that evolved in our species during the long slog known as The Pleistocene with today’s behavior in the modern predator-free food-rich world. And, it is a very sound argument. If, by “sound” you mean “sounds good unless you listen really hard.”

I list this argument among the falsehoods, but really, this is a category of argument with numerous little sub-arguments, and one about which I could write as many blog posts as I have fingers and toes, which means, at least twenty. (Apparently there was some pentaldactylsim in my ancestry, and I must admit that I’ll never really know what they cut off when I was born, if anything.)

Before going into this discussion I think it is wise, if against my nature, to tell you what the outcome will be: There is not a good argument to be found in the realm of behavioral biology for why American Women shop while their husbands sit on the bench in the mall outside the women’s fashion store fantasizing about a larger TV on which to watch the game. At the same time, there is a good argument to be made that men and women should have different hard wired behavioral proclivities, if there are any hard wired behavioral proclivities in our species. And, I’m afraid, the validity from an individual’s perspective of the various arguments that men and women are genetically programmed to be different (in ways that make biological sense) is normally determined by the background and politics of the observer and not the science. I am trained in behavioral biology, I was taught by the leading sociobiologists, I’ve carried out research in this area, and I was even present, somewhat admiringly, at the very birth of Evolutionary Psychology, in Room 14A in the Peabody Museum at Harvard, in the 1980s. So, if anyone is going to be a supporter of evolutionary psychology, it’s me.

But I’m not. Let me ‘splain….
Continue reading Why do women shop and men hunt?

New Primate Fossil Informs Us of the Ape-Monkey Split During the Oligocene

ResearchBlogging.orgThe newly reported Saadanius hijazensis may or may not be a “missing link” but in order for this monkey to climb onto the primate family tree, a new branch had to be sprouted. So, not only is Saadanius hijazensis a new species, but it is a member of a new taxonomic Family, Saadaniidae, which in turn is a member of a new Superfamily, Saadanioidea. Why is this important? It’s complicated. But not too complicated.

The fossil was found while University of Michigan paleontologist Iyad Zalmout was busy looking for dinosaur fossils in western Saudi Arabia. He found the monkey, from a much later time period, instead. Ooops.
Continue reading New Primate Fossil Informs Us of the Ape-Monkey Split During the Oligocene

Keep an eye on the prey: You’ll find the predator

In Robert Gardner’s documentary film Dead Birds, the men of a highland New Guinea village guard the perimeter of the territory, watchful for men of the neighboring group who may be intent on sneaking into the gardens to capture and kill an unwitting child or woman in order to avenge a prior death. But they don’t see the men sneaking through the dense riparian forest. They don’t even look for them. Rather, they see the birds fly from their preferred habitat where they are foraging or resting, startled into the open by … something. The birds belie the predator.
Continue reading Keep an eye on the prey: You’ll find the predator