Several theories have been proposed by scientists to explain the two mass extinction events which took place on the earth 250 and 200 million years ago. The Permian-Triassic catastrophe (250 million ...

Rapid changes in marine oxygen levels may have played a significant role in driving Earth's first mass extinction, according to a new study. Rapid changes in marine oxygen levels may have played a ...

Identifying a killer can be difficult when it seems like every murder weapon imaginable has been used in the crime, and when the victim is the entire planet. About 252 million years ago, a rich and ...

In today’s state of overwhelm, it’s easy to spend more time consumed with the present and the future than contemplating the events of the past. This constant forward motion can, at times, become ...

Ancient sediments that once resided on a lake bed and the ocean floor show sulfur isotope ratios unlike those found in other samples from the same time, calling into question accepted ideas about when ...

Just as the first complex animals were settling into Earth’s oceans, oxygen levels fell dramatically and wiped many of them out. The finding shows that the birth of complex life was beset with dangers ...