Mass Extinctions

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According to a study, the Sixth Mass Extinction is underway. And this time, it is entirely caused by human activities.

What is Mass Extinction?

A mass extinction event is when species vanish much faster than they are replaced. This is usually defined as about 75% of the world’s species being lost in a ‘short’ amount of geological time – less than 2.8 million years.

Earth has so far undergone five mass extinctions caused by natural phenomena, either due to natural climate shifts or asteroid impacts. After each of these extinctions, it took millions of years to regain species comparable to those that existed before the event.

Now the sixth mass extinction is underway. This extinction is entirely caused by human activities. Researchers have described it as the “most serious environmental problem” since the loss of species will be permanent.

What does the study say about the sixth mass extinction?

The study has said that the sixth mass extinction has been going on since at least the 16th century.

Earth was once home to two million known species. But since 1500 CE, as many as 7.5%-13% of them may have been lost, meaning from 150,000 to 260,000 different species.

The study also said that some people deny this sixth mass extinction. But this denial was due to a biased view that focuses only on mammals and birds, ignoring the die-off rate of invertebrates.

Note: An Invertebrate is any animal that lacks a vertebral column, or backbone. More than 90% of all living animal species are invertebrates. They include animals as diverse as sea stars, sea urchins, earthworms, sponges, jellyfish, lobsters, crabs, insects, spiders, snails, clams, and squid.

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