There were 5 major times in history that mass extinctions occured.
These were in the:
1) Late Ordovician
2) Devonian
3) End of the Permian
4) Late Triassic
5) End of the Cretaceous
The Permian extinction was the largest and killed off 90% of the Earth's species. The cause is believed to be related to life already being stressed by a very dry climate, accompanied by prolonged periods of volcanic activity (the Siberia flood basalts).
The End Cretaceous extintion is the most famous as it is what ended the dinosaurs. The most common belief is that the cause was a 11km wide comet striking the Earth. However this is hottly debated as at the same time their was also a long period of volcanic activity in what is now India (the Decan Traps). Also some say that the rise of small mammals ended the dinosaurs by raiding their nests. It is possible that all these played a role.
The exact cause of many mass extintions is still being activly studied and debated by scientists
The five mass extinction events were
A mass extinction is a relatively sudden, global decrease in the diversity of life forms. Mass extinctions have occurred periodically throughout the existence of life on Earth. To be a mass extinction, the following must occur:
Extinctions occur all over the world.
A large number of species go extinct.
Many types of species go extinct.
The extinctions are clustered in a short amount of geological time (a few million years is very short in terms of geological time).
The five largest mass extinctions in Earth's history occurred during:
The late Ordovician period (about 438 million years ago) - 100 families extinct - more than half of the brazen and reshaped species extinct.
The late Devonian (about 360 Maye) - 30% of animal families extinct.
At the end of the Permian period (about 245 mya) - Trilobites go extinct. 50% of all animal families, 95% of all marine species and many trees die out.
The late Triassic (208 mya) - 35% of all animal families die out. Most early dinosaur families went extinct, and most synapses died out (except for the mammals).
At the Cretaceous-Tertiary (K-T) boundary (about 65 mya) - about half of all life forms died out, including the dinosaurs , pterosaurs, plesiosaurs, masseurs, ammonites, many families of fishes, clams, snails, sponges, sea urchins, and many others.
Currently, during the modern Holocene epoch, there is large number of extinctions occurring. Much minor extinction has also occurred through Earth's history.
the cause was from someone taking a big dump
somone take big popy and thehn mend born
the holocene extinction
false
During the time period known as the Triassic period, reptiles dominated the Earth. Particularly, archosaurs, which included early dinosaur ancestors and crocodile-like creatures, were common. This period also saw the rise of the first mammals and the proliferation of various marine life forms.
Precambrian
Yes, earth has been hit by asteroids before. The effects have ranged from localized devastation, to worldwide mass extinction events.
The Cretaceous–Tertiary extinction event 65 million years ago was the last mass-extinction, and many believe that humans are causing a mass-extinction right now.
Mesozoic
five
They are the end-Ordovician extinction, end-Devonian extinction, end-Permian extinction, the Triassic extinction, end-Cretaceous extinction.
the evolution of mammal like reptiles and the biggest mass extinction ever on the history of the earth which killed 90% of all life
The Permian was the last period of the Paleozoic Era, spanning 299-351 million years ago. It was a time during which reptiles diversified. It ended with the Permian-Triassic extinction event, the largest mass extinction in Earth's history.
The Permian extinction is called the "Great Dying" because it was earth's largest mass extinction which wiped out as much as 95% of life.
we do it... hard
The largest extinction event known is the Permian-Triassic Extinction Event, 250 million years ago. It is nicknamed "The Great Dying" in reference to how 96% of all known marine animals and 70% of all known terrestrial vertebrates at the time went extinct due to climatic changes because of volcanic eruptions and the formation of Pangaea.
If the Cretaceous mass extinction had not occurred, reptiles would today be the largest land animal in the world. At the time, reptiles were the largest animal group on Earth.
The largest mass extinction in the history of the earth could have been triggered off by giant salt lakes, whose emissions of halogenated gases changed the atmospheric composition so dramatically that vegetation was irretrievably damaged.
false
The history of the planet.A record of the geologic events and life forms the earth's history.