Eager Beavers

Introduction
This week's Science (Feb. 24, 2006, subscription required) includes a perspective by Thomas Martin, inspired by the report by Ji et al of a beaver-like mammal that lived in the mid-Jurassic. It is becoming clear that mammals have been around a lot longer than previously thought. This also takes down the supposedly totally dominant dinosaurs a notch or two. Mammals were successful despite the presence and dominance of the dinosaurs. This provokes a number of reflections on evolution ...

Introduction

This week's Science (Feb. 24, 2006, subscription required) includes a perspective by Thomas Martin, inspired by the report by Ji et al of a beaver-like mammal that lived in the mid-Jurassic. It is becoming clear that mammals have been around a lot longer than previously thought. This also takes down the supposedly totally dominant dinosaurs a notch or two. Mammals were successful despite the presence and dominance of the dinosaurs.

This provokes a number of reflections on evolution ...

Every child has wondered at the power of the dinosaurs, classically pictured in the film, Jurassic Park. The idea has been inculcated in us that for more than 100 million years - what a long time! - dinosaurs ruled over all other creatures cooly, without mercy. We have been taught our mammalian ancestors were pipsqueaks crawling around in tunnels and other hiding places.

That outline of Earth's Mesozoic and Jurassic biology comes to us largely from discoveries of a recent generation of American paleontologists. Before that, dinosaurs were presented as stupid, plodding reptiles who dominated, but not completely. The quick, calculating Velociraptors in Jurassic Park are the result of research findings that considerably upgraded dinosaur blood circulation, method of locomotion, brain size, etc. Most significant is the modern finding that the birds all around us are closely related to dead dinosaurs. Our knowledge of birds transfigures the previously cumbersome reptiles, but also makes them the more fearsome, as in Hitchcock's Birds.

While those results of American science are not in dispute, what has not been accounted until the last decade are the immense paleontological treasures of Mongolia and China. Only recently are those Asian deposits being examined and reported in the International scientific press, reflecting the increasing importance of China in the human world. For example, not too long ago, Chinese scientists found a putative "missing link" between Archaeopterix and dinosaurs, complete with feathers. Now they've found a beaver-like mammal that lived in the midst of bloodthirsty reptiles, and survived.

Other findings in Africa keep pushing back the origins of hominids. The lineage of Homo sapiens is far longer than anyone thought just a few years ago. It took at least 8 million years, and maybe more, to develop us. Should this drive us into the arms of the Intelligent Designers? NO, absolutely not! It should teach us that making an intelligent critter is not easy, and not to expect rapid progress in AI. Intelligence - or at least the sort we value - is the consequence of trillions - not just millions or billions - of evolutionary experiments. It didn't have to happen, but it did. We are the lucky result. (By "lucky," I do mean statistical, probable.) While it is difficult to develop intelligence, it is not impossible.

These findings certainly promote reconsideration of "dominace." The dinosauric mafiosi were unable to get rid of the pesky beaver-like critters living openly along shores. Our mammalian ancestors also avoided crocodilians, sharks and a bevy of other expert hunters in their struggle to survive. We don't know why they avoided extermination. Perhaps nearby water and land provided a refuge from whichever hungry monster pursued them, if the monsters were not adapted to both environments. Perhaps being warm blooded gave mammals an advantage in cooler climates. Maybe slightly more devious brains anticipated reptilian strategies, so avoided deadly traps. Whatever combination of abilities those ancient proto-beavers had, they managed to lead their lives out in the open, right under the jaws of predators. A scary existence, but an existence nonetheless.

This exposes a feature of dominance not often seen. Whether we think about dominant dinsoaurs or Imperial regimes, all too often we believe them omnipotent, always carrying the day and everything before them. There is no rat too large or small who cannot be rooted out and liquidated; or so we think. But the difficulties of the American Empire in Iraq, and the Middle East generally, belie that conception. The American Bandit is unable to get his contracts on Osama Bin Laden fulfilled. Why, then, should we think our remote ancestors any less capable when faced by far less competent adversaries?

These discoveries about ancient life should give heart to those opposed to modern Imperial giants. If the dinosaurs had wiped out every edible mammal, perhaps they would not have survived so long. The dinosauric need to eat is also interested in promoting the survival of its food. There is an inevitable reliance of the dominant on the dominated. That reliance makes room for lesser species to live, even live well. Thus, Chinese Communists must grind their teeth when faced with rich Shanghai entrepreneurs and Hong Kong merchants, just as Wall St tycoons growl about the insolence of American trade unions and workers. Perhaps the same relationship exists between the Imperial center and Arabia, for, today, surely America cannot survive without Arabs.