Two hundred and fifty-two million years ago, life nearly became extinct. This is known as the Permian extinction and at this time, it was the biggest mass extinction to have ever happened on our planet.
So, how big was it? Well, over 90 percent of animals, or species, living in the ocean became extinct. And over 70 percentof species living on land became extinct. And how do we know? Well, we know from the fossil record. Fossils are found mostly in what is known as sedimentary rocks. And sedimentary rocks are layered down on top of each layer, so we find the oldest rocks at the bottom, typically, and the youngest rocks on top. This means that we can see what was happening to life over the ages. So what we find in rocks from these times is we find that there’s a lot of life in the time before 252 million years ago and not a lot after, straight after that time. Many types of species of animals and plants don’t make it through this time boundary, they’re not found in the younger rocks at all. And that’s how we know that this is a time of mass extinction.
So, what caused this mass extinction? Well, scientists have been puzzling over that question for decades. But it seems that all the evidence is pointing towards climate change as being what caused this extinction. And what triggered that climate change? Well, some scientists think that it may have been severe volcanic activity that occurred in Siberia, and they think that because of the geological evidence.
So, it’s not all bad news. Many animals did survive this extinction event. For example, sharks survived and they populate our ocean today. The reptiles that then went on to evolve into dinosaurs and dominate the world for millions of years, they survived. And also, mammal-like reptiles survived, which might not sound that exciting at first, but those types of animals then went on to evolve into the different forms of mammals we see today, including ourselves.