Humans are causing the sixth mass global extinction

Mindy Sparks
October 19, 2018

Prof Douglas Futuyma at Stony Brook University in the USA, who was not part of the research team, said: "They have made a dramatic and convincing statement of how much evolutionary diversity has already been lost".

Given the current rate at which humans are exterminating animal and plant species, researchers at the Aarhus University and the University of Gothenburg calculated how long would it take for biodiversity to recover. An Aarhus headed research team figured out that if the present preservation efforts are not enhanced; so many mammal species will become extinct in the course of five decades that nature will require 3-5 million years to recuperate. There are only 50 years old, and mass extinction will reach its peak and to restore the biodiversity of the planet will take from 3 to 5 billion years.

On Earth may come the sixth mass extinction - antropoceno era, during which the environment of the planet will change so that most of the species of animals and plants will disappear.

The International Union for the Conservation of Nature predicts that 99.9 percent of critically endangered species and 67 percent of endangered species will be lost within the next 100 years. As habitats and climates change, species that can't survive die, and new species slowly emerge.

Extinction on Earth happening faster than evolution?

The team of researchers used an extensive database of mammals that includes not only existing species but also those that went extinct since Homo sapiens expanded across the globe.

In order to establish the time required for mammalian species to recover to biodiversity levels seen before humans entered the big picture, the researchers performed advanced evolutionary simulations on powerful computers.

Even during the last glacial period (left) on Earth there was a great variety of large mammals, nearly all of which our time (center) has disappeared. If the extinction rate doesn't start falling for another 20-100 years, more species will likely disappear, causing greater diversity loss, the study said.

Matt Davis, an Aarhus University paleontologist who was leading the study, pointed to the shrew as an example.

"There are hundreds of species of shrew, so they can weather a few extinctions", he continued.

"Large mammals, or megafauna, such as giant sloths and sabre-toothed tigers, which became extinct about 10,000 years ago, were highly evolutionarily distinct", Davis said in a statement. This rate of extinction is increasing over the course of the last few years.

They inspected several scenarios, modeling the complex evolutionary relationships between existing and extinct mammals, finding that even under the most optimistic scenario, it would still take up to five million years for the mammalian life to regenerate its lost branches and twigs of the evolutionary tree. There were only four species of saber-toothed tiger; they all went extinct'. This indicates that researchers could research the total effect of our species on other mammals.

Large mammal species, the researchers warn, are disproportionately at risk of dying out altogether.

"The few remaining giants, such as rhinos and elephants, are in danger of being wiped out very rapidly", he continued.

Matt Davis from Aarhus University says, 'It is much easier to save biodiversity now than to re-evolve it later'.

Though their calculations regarding extinction on Earth are still dire, the scientists think their work could be used to figure out which endangered species are evolutionarily unique and represent the most important parts of evolutionary history on Earth.

Other reports by Iphone Fresh

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