Oct

23

The visual evidence of Life adapting to ever changing environments over geologic time is one of much interest to the ichnologist (and hopefully to some on this board). Ichnology is an arcane field partially contained within the bounds of paleontology that employs a rather unusual, behavior-based taxonomic nomenclature for the often intricate and geometrically diverse traces left behind by life forms (i.e. tracks, tubes, burrows, fecal material, etc). Many times the actual creatures that left the traces are not known.

Beyond enjoying the outdoors, the wonders and expressions of nature, and beating at rock outcrops with an Estwing hammer, why (you may ask) the heck would anyone other than an eccentric geologist be interested in such an esoteric area of science? Well for one, the folks who spend billions of dollars a year drilling for petroleum like to develop models of past environments that will give them an edge in locating (or extending) reservoirs of oil. Recognizing depositional patterns can greatly increase odds of drilling and constructing a well in the right place (vertically and horizontally) and finding areas where source, reservoir, trap, and seal come together in perfect stratigraphic harmony. For the oil man there is nothing worse than throwing money down a hole— particularly an expensive “dry” hole.

Charles Darwin too had an interest in and a profound appreciation of what now would be called neoichnology when he wrote his study entitled “The Formation of Vegetable Mould through the action of worms with observations of their habits”. Darwin was very impressed by the cumulative effects created by the small, daily efforts of the common earthworm—the long-term creation of a soil horizon and the recycling of organic material on the surface of the Earth. In fact Darwin stated “The plough is one of the most ancient and most valuable of man’s inventions; but long before he existed the land was in fact regularly ploughed, and still continues to be thus ploughed by earth-worms. It may be do doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.” Many of his observations on the ichnologic equivalent of bioturbation were no doubt done at his country home outside of London.

For the most part, however, ichnology is a field with a relatively young history. As related in his American Scientist Online article, “In Search of the Optimal Scumsucking Bottomfeeder”, Brian Hayes notes that trace fossils provided “the inspiration for one of the earliest computer simulations of animal behavior, published in 1969 by David M. Raup of the University of Rochester and Adolf Seilacher of the University of Tubingen”. Later artificial life simulations also show the influence of trace fossil research.

But are the wondrous, geometrically-aligned, trace fossils visual representations of animal behaviors focused on the optimal means to acquire food with the expenditure of the least amount of energy? Are they an animal world corollary to Chair’s observations on Man trying to “satisfy his desires with the least amount of effort”? As Brian Hayes notes the food foraging model “…is still the leading hypothesis, but perhaps there is room for doubt”. There also is some doubt as to whether these behaviors really evolved in complexity over time or that different trace types are even representative of different behaviors.

In “Let Us Prey: Simulations of Grazing Traces in the Fossils Record”, Plotnick and Koy of the Univ. of Illinois at Chicago, suggest that “Changes in the occurrence of trace fossil types over time, in particular during the Precambrian-Cambrian transition, may thus be largely a consequence of the development of spatial heterogeneity on the ocean floor, rather than the development of new and more complex behaviors.” In conclusion Plotnick and Koy state “…that it is possible to simulate many possible trace fossil morphologies, including random movements, zigzags, and spirals, with a single simple behavior.” Touche for the lumpers.

One might take away from all this that one has to be careful with conclusions drawn strictly from visual data and the gravitational effects of hypotheses presented by earlier researchers. The mind seemingly also has a strong tendency to embellish with interpretation of visual data. An intellectual shave with Occam’s Razor to one’s scientific theories, however, appears preferable in most cases to a buzz cut from the Mistress of the Markets.

It is an interesting parallel that some of the complexity, fractal and physics-wielding gurus, brought their expertise to bear on the subject of paleontology. Like their forays into the financial realm they have found things in the “soft” life science field to be a bit more complicated than they imagined. Lesson: conclusions drawn strictly from formulae and without knowledge gained from real world observation also can lead one astray.

Ichnology then is a science that seeks to understand the environmental influences that effect Life’s movements through the substratae of the Earth and to identify and interpret components of behavior that are random and those that are representative of organized activity — all the time that the local, regional and global environment is being changed by that behavior.

Remind you of anything?


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