Mass extinctions have occurred five times in Earth's history. The Permian and Cretaceous extinctions removed a large percentage of organisms from the planet. How did these extinctions contribute to the patterns of biodiversity we see today

Species that remain after the extinction are able to radiate, new adaptations arise, and these produce the diversity seen today.

Explanation:

It should be understood that extinction  can be described as the termination of a particular kind or specie of organism. This means that , that particular kind or specie of the organism  does not exist any longer.

There are a number of factors that contribute to the extinction of an organism. These include

* An introduced species A specie of organism that is newly introduced to a habitat may start killing the resident organism, or the introduced itself may be killed. And this either way may lead to extinction of one of the organism.

* Pollution Presence of pollution in a habitat may kill all the resident organism

* Population growth...leads to the survival of the fittest, only the strong organism will survive.

* Habitat loss natural disaster in a habitat may lead to the death of the resident organism.

* Over-consumption or killingthis is one of the major factor that leads to extinction of organism.

Biodiversity is the variety of plants and animals in a particular habitat or in the world at large.

In summary,After the Permain and Cretaceous extinction, the survived organisms developed adaptation ability, which will definitely result to the development of some features, and this contribute to biodiversity.

answer; in the united states the plains include the great plains of the west and the tail grass prairie to the south of the great lakes extending east to the appalachian plateau