What is the role of Mass Extinction in Evolution?

What is the role of Mass Extinction in Evolution?

Answer:

Extinction occurs when all members of a species, in the wild and in captivity, have died. Though extinction is a well-known and studied phenomenon in modern times, it was first described relatively recently in human history. In the late 18^th Century, a French naturalist named Georges Cuvier (1769-1832) was the first person to propose that species could become extinct and that life on Earth did not exist in a constant, unchanging state. While the exact mechanisms and varying extinction speeds were poorly understood then, Cuvier used examples of fossilized species that could no longer be found anywhere on Earth as evidence for the phenomenon. Over the next century, the idea was further bolstered by many scientists, including Charles Darwin. Today we know that over 99 percent of all species that have lived are now extinct.

Definition:

Mass extinctions, also known as extinction events, occur when there is a massive and sharp decline in global levels of biodiversity. When this occurs, the rate of extinction exceeds that of speciation (the rate at which new species arise). At least six mass extinction events are known to have occurred: the Ordovician-Silurian, Late Devonian, Permian-Triassic, Triassic-Jurassic, Cretaceous-Paleogene, and Holocene. The Holocene extinction event is currently ongoing.

Mass extinction can also play a creative role in evolution, stimulating the growth of other branches. By removing so many species from their ecosystems in a short period of time, mass extinctions reduce competition for resources and leave behind many vacant niches.

Explanation:

At the most basic level, mass extinctions reduce diversity by killing off specific lineages, and with them, any descendant species they might have given rise to. In this way, mass extinction prunes whole branches of the tree of life. But mass extinction can also play a creative role in evolution, stimulating the growth of other branches.

The extinction of species is not normally considered an important element of neo-Darwinian theory, in contrast to the opposite phenomenon, speciation.

Despite uncertainties, extinction probably contains three important elements.

(i)                 For geographically widespread species, extinction is likely only if the killing stress is one so rare as to be beyond the experience of the species, and thus outside the reach of natural selection.

(ii)              The largest mass extinctions produce major restructuring of the biosphere wherein some successful groups are eliminated, allowing previously minor groups to expand and diversify.

(iii)            Except for a few cases, there is little evidence that extinction is selective in the positive sense argued by Darwin. It has generally been impossible to predict, before the fact, which species will be victims of an extinction event.

There are two-three known roles of mass Extinction. They are

·         Mass Extinction help in the Extinction of large-sized species which need a lot of food for themselves to live comfortably. So, they usually eat large no. Of animals for their survival which could cause the stoppage of the evolution of that time species which are undergoing the process of ' slow evolution.

·         It helped the species that are better to survive because you know the fact that the pieces which are not much evolved or adapted to the harsh condition should be removed by natural selection as said by Darwin.

So, we can say that it is a major part of evolution. And of it some way helped in the survival of man on Earth.