Saturday, July 15, 2006
Could a predatory relationship between two ancient species reveal an early driving force of evolution? Absolutely, according to Mark Wilson, professor of geology at The College of Wooster, and Paul Taylor of The Natural History Museum in London.
In an article from the July issue of Geology, titled "Predatory Drill Holes and Partial Mortality in Devonian Colonial Metazoans," Wilson and Taylor explain how a 380-million-year-old animal, known as a hederellid, reacted to repeated attacks by an unknown assailant.
Hederellids are extinct colonial animals that made skeletons of branching tubes. According to the two scientists, new evidence shows that hederellids responded to these predators, who drilled through their tubes (most likely with a radula-like device), by plugging the holes with skeletal patches secreted by internal tissues. They also closed off damaged sections with skeletal plugs.