Question

What is meant by mass extinction?

Answer 1

The word extinction means to cease to exist or to stop from being there. It is mostly used in the field of biology and there are many factors for this process. Mostly it refers to extinction of a species but also can be referred to non biological beings such as volcanoes or vast water bodies. If something that belongs to a class does not exist we call it extinction.

Complete answer:
Mass extinction means a majority of all the species are vanished or about to be not seen anymore in a particular geographical area. It is also known as bio-crisis. The biodiversity of the geography gets reduced to a drastically low level such that the existence of life forms can be questioned. Main reason for this is the climatic and atmospheric changes due to changing chemical composition of the Earth. There are many reasons for the species to get extinct which includes activities done by man like deforestation, oil leaks in the ocean disturbing aquatic life, air, water and soil pollution, global warming, usage of plastic and non degradable utilities, industrial wastes, illegal hunting and fishing.
When the natural habitat of an organism is disturbed, it slightly evolves to survive. But if the change is drastic and sudden, the life forms cannot cope with the changes and cannot survive. Reproduction rate also falls very low causing the entire interdependent biome to gradually undergo extinction. Hence to prevent mass extinction in future , we should reduce deforestation, pollution, global warming and hunting.

Note:
Some of the mass extinctions in the history are Permian-triassic and Triassic-jurassic Extinction. That occurred 250 million years and 210 million years respectively, where many number of vertebrates were unable to cope with the drastically changing climate and the weather conditions not favouring their life, have gone extinct.