Question

The Racing Extinction Documentary discusses the 6th Extinction. What is mass extinction? How many have occurred in the past? What is the 6th Extinction and how does it compare to previous extinctions? What are you doing to drive the 6th Extinction? What could you do to stop it?

Answer 1

Ans. Mass extinction is the process which leads to destruction of more than 50 % of the total biodiversity that existed in the earth at a point of time. It marks the sharp decline of biodiversity in the earth. It is different from an ordinary extinction, Extinction is the process or event that leads to decline of a particular species or some species due to lack of survival ability. On the other hand, mass extinction refers to the decline of various organisms as a whole such that it affects the biodiversity of the earth. It could be due to various factors like natural disasters like catastrophic volcanic eruptions, asteroid impacts, climate change etc.

There have been 5 mass extinction events in the past. These are described below:

1. The first mass extinction event took place during the Ordovician period when most of the aquatic organisms, mainly the Graptolites turned extinct. It took place about 440 millions of years back. It was the initial phase of the life formation, when aquatic organisms were flourishing. This mass extinction was brought about by severe climate changes. Firstly, there was a phase of Ice Age. The water bodies froze and the remaining ones had their sea level lowered. Some species died due to their lack of adaptation. Another reason triggering this mass extinction was the sudden ending of the Ice Age. The sea levels rose too fast and the remaining organisms were not able to adapt this fast.
2. The second mass extinction event took place during the Devonian period about 375 million years ago. It is significant since the organisms which came into existence during the Cambrian explosion went extinct, especially the Trilobites, which were mainly benthic in nature. This was the time during which the autotrophs and green plants were evolving. The strong roots of the plants were bringing about upheaval of the surface which was directly releasing the nutrients from the soil to the receiving water bodies. This led to eutrophication type of processes and thus resulted in the formation algal scums. This led to the depletion of oxygen at the bottom regions, thus the trilobites went extinct.
3. The third mass extinction event took place during the Permian period about 250 million years ago. This is considered one of the greatest mass extinction events, since it wiped out almost 96 % of the total living organisms both land and aquatic flora and fauna. The corals, especially the tabulate ones were completely destroyed. The probable causes are volcanic eruptions, asteroid impacts which set carbon dioxide free in the atmosphere along with the emission of methane by these processes and methanogenic bacteria. These bacteria grew more in such environment and occupied all the available land and aquatic environment thus wiping out all other life forms.
4. The fourth mass extinction event took place in the Triassic period about 200 million years ago. The cause is volcanic eruptions which led to debris flowing all over that perished a lot of organisms. It released considerable carbon dioxide concentration which acidified the water bodies thus killing most of the aquatic organisms.
5. The fifth mass extinction event is known as the K-T mass extinction or Cretaceous-Tertiary mass extinction event. It wiped out the dinosaurs along wit other organisms. The probable cause is the asteroid impact.

The earth is believed to be currently going through the sixth mass extinction event. Numerous flora and fauna are turning extinct. Some are also endangered, some are vulnerable, and this number is increasing at a fast pace. The difference between the previous mass extinction and the sixth mass extinction event is that the previous ones were mediated by natural processes like volcanic eruptions, natural induced climate change and asteroid impacts, whereas the sixth one is induced by anthropogenic activities. Humans are leading to the sixth change. The climate change is also human mediated.

We humans are destroying the forests and lands for our commercial needs and accomodating the increasing population. So we are destroying the habitats of different flora and fauna. Moreover we are killing the plants and animals for their medicinal or economic uses, thus their numbers are falling with time. We are burning down forests to draw more land to be put to use. We are destroying the rain forests which are the lungs of our earth. We are polluting and contaminating the different spheres of environment like water, air and land which is affecting the plants and animals. Our rapid and relentless use of fossil fuels release carbon dioxide which is a potent gas for global warming. Thus it is also inducing the climate change which is again causing wiping out of plants and animals.

We can still avoid the 6the mass extinction from turning into havoc. We can stop deforestation and start reforestation. We can preserve the flora and fauna in their natural habitat by conserving the reserve forests, national parks, and sanctuaries. We should save energy wherever possible to reduce the energy demand and thus lesser use of fossil fuels can be accomplished. One of the best ways is to shift to renewable energy sources which do not pollute the environment.