The world's first mass extinction occurred 540 million years ago. New evidence published in Proceedings of the Royal Society B suggests that this mass extinction wasn't caused by the usual suspects like a meteorite impact or volcanic activity, but by organisms capable of altering their own environments.
The study looked at several communities of Ediacarans, which were the first multi-cellular organisms to evolve. Ediacarans were some of the first organisms that utilized oxygen. Oxygen was toxic to most microbes because at this point in Earth's history, the atmosphere was mostly devoid of oxygen.
Fast forward to the Cambrian explosion. This is a 25-million year period in Earth's history where animals exploded onto the scene (i.e., vertebrates, mollusks, arthropods, sponges, and jellyfish.) These complex animals preyed on the extremely passive Ediacarans. These new animals essentially became "ecosystem engineers" and were ultimately responsible for the disappearance of the Ediacaran.
Let's fast forward to the present day. The paper links ties with this first mass extinction and our present day situation. No other species in the history of the Earth has altered the landscape and climate like humans have. Hopefully we can learn from this past mass extinction and avoid a future mass extinction.