Scientists Find Clues to What Could Be the First Mass Extinction of Animals on Our Planet

Approximately 550 million years ago, at the end of the Ediacaran Period, the majority of species on Earth died out due to a decline in worldwide oxygen supply, according to a new study by geobiologists at Virginia Tech. This early mass extinction of almost 80% of creatures during this time period is demonstrated by a study led by Scott Evans from the Department of Geosciences in the Virginia Tech College of Science.

Mass extinctions are well recognized as significant steps in the evolutionary trajectory of life on this planet. Here, we document the oldest known extinction of animals and test for potential causes. Our results indicate that, like younger diversity crises, this event was caused by major shifts in environmental conditions. Particularly, we find support for decreased global oxygen availability as the mechanism responsible for this extinction.

Many animal species perished as a result, but it appears that those whose anatomical makeup and social habits indicated a high oxygen demand were hit particularly hard. This indicates that the extinction event, like all other mass extinctions in the geological record, was caused by environmental factors.

Species extinction on a huge scale, as well as significant disruption and reorganization of the ecosystem, can result from environmental changes like global warming and deoxygenation events. Many studies, including this one on the earliest known extinction in the fossil record, have shown this to be the case. Thus, this research enlightens us as to the biosphere’s potential long-term response to the current state of environmental change.

The oxygen level in the atmosphere suddenly dropped, but why? That has not been settled yet. Animals that become extinct appear to be reacting to a decreased global oxygen supply, which may be caused by a variety of factors, including volcanic eruptions, tectonic plate displacement, an asteroid strike, etc.

This study adds to a growing body of evidence indicating the perilous effects of our present climate catastrophe on animal life by showing that the first global extinction of animals on Earth was also triggered by catastrophic climatic change.