ScienceDaily (Jan. 12, 2011) —
Ammonoid markers. A 50-million-year fossil record of ammonoids includes two kind of the nautilus-like creatures, swimmers and floaters. At two points of mass extinction, the swimming ammonoids disappear completely from the fossil record. (Credit: Image courtesy of Brown University)
Geologists at Brown University and the University of Washington have a cautionary tale: Lose enough species in the oceans, and the entire ecosystem could collapse. Looking at two of the greatest mass extinctions in Earth’s history, the scientists attribute the ecosystems’ collapse to a loss in the variety of species sharing the same space. It took up to 10 million years after the mass extinctions for the ecosystem to stabilize.