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October 16 (UPI) – Evolution can not keep pace with the ecological damage caused by humans.
According to a new study, the extinction rate in mammals accelerates, thus limiting the natural defense mechanism of nature against ecological damage, namely the evolution.
As a result of the five massive extinctions of the Earth, evolution has allowed the Earth's animal population to regenerate and diversify, filling gaps left by extinct species.
The sixth mass extinction of the Earth is under way, but human beings have already done considerable damage, damage that will not be repaired soon. According to the latest research, published Tuesday in the journal Proceedings of the National Academy of Sciences, it will take 5 to 7 million years to evolve to restore mammalian diversity to a pre-human level.
Scientists from the University of Aarhus in Denmark have studied the mammalian fossil record to accurately quantify the human impact on mammalian diversity. For thousands of years, humans have been targeting the largest species on the planet. Large species tend to have fewer parents. When they are eliminated, the biodiversity of the Earth is greatly reduced.
"Large mammals, or megafauna, such as giant sloths and saber-toothed tigers, which have been extinct for about 10,000 years, were very distinct from the point of view of evolution," said in a statement Matt Davis, paleontologist from Aarhus. "Since they had few close relatives, their extinctions resulted in the cutting of whole branches of the evolutionary tree of the Earth."
"There are hundreds of species of shrews, so they can withstand some extinctions," said Davis. "There were only four species of saber-toothed tigers, all of which have disappeared".
In the last few million years, mammals have declined everywhere they went. Today, the largest mammal species on Earth are still under threat. To better understand the ecological damage caused by the ongoing mass extinction on Earth, scientists have calculated the time it would take for mammalian biodiversity to recover.
Researchers used powerful evolutionary simulations to estimate recovery time based on past and future extinction rates. The models took into account evolutionary relationships and body size in living and endangered mammal species.
In the best case, the evolution will restore pre-human mammal diversity levels by 5 to 7 million years ago. The scenario assumes that humans will stop destroying their habitats and eradicating species.
Models have shown that planned extinctions over the next 50 years will require 3 to 5 million years of recovery time.
"Although we once lived in a world of giants: giant beaver, armadillos and giants, giant deer, etc., we are now living in a world increasingly poor in wild mammals," said Christian Svenning, professor in Aarhus. "The few remaining giants, such as rhinos and elephants, may disappear very quickly."
Humans can help evolution do its work by protecting habitat and prioritizing the conservation of endangered and evolutionarily diverse species.
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