||October 25, 2002 GSA Release No. 02-47 Sod Busters Along the
Old Cambrian Trail If you've ever had to scrape a barnacle, you
can blame a trilobite for your trouble. The advent of trilobite-
tilled, worm-worked muck a half-billion years ago may have
helped feed an explosive evolution of early animal life in the
oceans - including the sort of critters that today attach
themselves to boats and piers. In the placid days before what's
called the Cambrian Explosion of animal life, seafloor sediments
were laid down in neat, firm layers, coated by microbial mats
and remained undisturbed. Animals had no need to attach
themselves to anything because the seafloor was firm and
reliable. Then along came animals that had figured out how to
mine the seafloor for food, changing the course of evolution
forever. David Bottjer of the University of Southern California
will explain the pivotal evolutionary role of what he calls the
Cambrian "sod busters" at the annual meeting of the Geological
Society of America on Monday, Octob