Mesozoic and Paleozoic
The Permian-Triassic extinction event, around 252 million years ago, marked the end of the Permian period and the beginning of the Triassic period. It is the most severe extinction event in Earth's history, wiping out approximately 95% of marine species and 70% of terrestrial vertebrate species. The Cretaceous-Paleogene extinction event, about 66 million years ago, ended the Cretaceous period and led to the extinction of the non-avian dinosaurs and about 75% of all plant and animal species.
Extinction did.
540 million years ago was the first mass extinction
The most devastating mass extinction occurred in the Late Permian (~250 million years ago).
Statistical analysis of the fossil record indicates somewhere around 35% of all species disappeared at the end of the cretaceous. (There is considerable margin for error in that figure--we don't have a good estimate for the number of species that exist today, even). http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Tertiary_extinction_event
Mesozoic
There are so far 4 Eras in the earths history. the one that started the beginning if the earths history: Precambrian Time. The one after that was the Paleozoic Era, which means "ancient life." next was mesozoic which means "middle life" the one we are in is called the Cenozoic Era which means" recent life." * All Eras ended with a mass extinction.
The event used to separate geologic eras is a significant change in Earth's environment or life forms, known as a mass extinction event.
mass extinction events, such as the Permian-Triassic and Cretaceous-Paleogene extinctions, that wiped out a significant portion of species on Earth. These events led to major shifts in the Earth's ecosystems and paved the way for new species to evolve in the following eras.
There were major asteroid impacts. #fuckschool #imheretohelp
Mesozoic
The Permian-Triassic extinction event, around 252 million years ago, marked the end of the Permian period and the beginning of the Triassic period. It is the most severe extinction event in Earth's history, wiping out approximately 95% of marine species and 70% of terrestrial vertebrate species. The Cretaceous-Paleogene extinction event, about 66 million years ago, ended the Cretaceous period and led to the extinction of the non-avian dinosaurs and about 75% of all plant and animal species.
Extinction did.
The effect of mass extinction is extinction, death of a mass
The Permian-Triassic mass extinction event marks the division between the Paleozoic and Mesozoic eras. This mass extinction, which occurred around 252 million years ago, resulted in the loss of about 90% of marine species and 70% of terrestrial vertebrate species.
An asteroid impact
The Permian mass extinction wiped out the highest percentage of all life forms, though I thought it was closer to 96%. It occurred 251 million years ago, between the Paleozoic and Mesozoic eras, and was caused by an extreme volcanic eruption in what is now Siberia.