People have destroyed more than 100 species – much more – on the doorstep or experience a large population.
Some scientists said we were attending a “sixth Mass disappearance” event similar to the one that destroyed dinosaurs 66 million years ago. This time, however, the culprit is the biological destruction caused by humans, not an asteroid of urban -sized.
However, in a new study published on Thursday, Plos Biology magazine, but it is stated that although the decline in biodiversity is real, insects, plants and animals do not disappear somewhere almost approaching mass extinction, the phenomenon, usually described by 75% of all types of loss. During the 4.5 billion years of land history, only five mass extinctions occurred.
Instead, the study states that the latest disappearances of plants and groups of animals are rare and are often limited to island habitats. In addition, the pace of extinction may be reduced, partly due to intense conservation efforts, especially for mammals and birds.
“One thing we emphasize, each of these extinctions is a tragedy and never had to happen and should not happen in the future,” said John Wiens, a research author, a professor of biology of the Ecology and Evolution of Evolution.
The impression of a 19th century artist about the cow of the Sterler Sea (Hydrodamalis gig), the disappearance of a water mammal. – Universal Historical Archive/Universal Images Group/Getty Images
Most extinctions are between birds and mammals
The analysis of Wiens and Cautn Kristen Saban, Harvard University, was based on 163,022 plant and animal species assessed by the International Nature Conservation Union. From 1500 AD. The focus was on the extinction of the tribe.
The tribe is a biological classification that is different but related species. For example, the Canis tribe has wolves, dogs, coyots and jackals. However, the tribe can also be monotype with only one, unique species such as Narwhal, Ginkgo Tree or Platype.
Wiens said he and Saban decided to analyze tribal level because it is likely to reflect more evolutionary history than species level analysis.
The study found that in the last 500 years, 102 tribes have disappeared – 90 animals and 12 plants. In addition, she found an extinction in two broader categories in the scientific classification system of life: 10 families with a group of tribes and two orders related to the family -related families.
Over the past 500 years, the tribes involving the Dodo (Raphus), the sea cow (hydrodamalis) and Cylindraspis, a group of recent giant turtles living in Mauritius and nearby islands. Other branches of the extinct life tree were the Honeyater Birds Mohoidae and the DinornHorms order, which grouped huge flights of birds such as New Zealand Moas.
The investigation has recognized some important restrictions on research. Most importantly, IUCN has not included many extinct tribes that have not been involved in a problem that can be particularly problematic for insects, with relatively few tribes with about half of all known species.
Most of these disappearances were between mammals (21 tribes) and birds (37 tribes), the study noted. They reflected a total of 179 species.
This indicator, positively, has rarely been done – only 0.45% of 22,760 tribes estimated by the International Nature Conservation Union, according to the study.
1910 MoA, Dinornnis Novaezealandiae, an illustration of a giant bird from New Zealand. – Florlegius/Universal Images Group/Getty Images
The analysis also found that most extinction occurred among the tribes who lived exclusively on the islands. For example, most bird disappearances occurred in the Mascarene Islands, Hawaiian Islands and New Zealand, the study noted.
The island’s habitats are particularly vulnerable to invasive species often caused by human settlers, Wiens said, and do not necessarily represent the broader risk of extinction.
Surprisingly, the analysis also shows that the level of extinction of the tribe began with a decline, and the fastest extinction percentage occurred in 1870, 1890 and 1900s.
“Instead, we found that the disappearance of plant and animal tribes is very rare, that they were mostly tribal found on the islands, and that these extinctions have actually slowed over the last 100 years, not rapidly accelerated,” Wiens said.
The study contradicts 2023. A study based on 5,400 vertebrates, which found that the genus level was “rapidly accelerating”, stating that “we are in the sixth mass extinction event.”
However, those studies focused on 5,400 vertebrate species and eliminated fish, insects and plants, given a small part of life on the planet, Wiens said.
The authors of this study Gerard Ceballa, Senior Researcher and Paul Ehrlich, a senior researcher at the Mexican National University of Autonomous University, and Bingo Emeritus Emeritus from Stanford University, said they accepted the sixth thesis of mass disappearance as
“In other words, thousands of species that have been lost in the last century would have been needed to disappear regularly for thousands of years. Trends are universal, affecting all organisms, including vertebrates, invertebrates, plants, fungi and germs,” CNN said. By mail.
“The concept of the sixth mass extinction and biodiversity crisis is scientifically combined,” they added.
The crisis and mass extinction of biodiversity
Although there is a broad consensus on the loss of broader biodiversity, there is much debate about the exact speed it takes place, and the scale, said Sadiah Qureshi, a science historian at the University of UK Manchester and the new book “Expired: The Author of the Unnatural Extraction History”. Qureshi, who did not participate in the study, said many geologists do not believe that the current crisis corresponds to the threshold of the mass extinction of the past in a geological record.
“While claims about the sixth mass extinction may be a call to act, apocalyptic statements about loss are as likely to feel as if they can’t do anything,” she said. By mail. “We have to remember that we can still make a significant difference, so it is important to keep hope.”
The current crisis and sixth mass extinction of biodiversity are separate concepts that should be disconnected, says Conrad Labandira, senior scientist and fossil arthropod curator in Smithsonian National Museum of Natural History in Washington, Washington. He did not participate in recent studies, but investigated the trends in insects, noting that many insect tribes had survived mass extinction.
“The current crisis of biodiversity exists … Meanwhile, the sixth mass extinction is explanatory,” said Labandira. “There should still be a call to act by emphasizing the preservation of natural ecosystems as a mechanism for preserving modern biodiversity, including those in danger.”
It is difficult to detect and document extinction, especially among poorly known groups, such as invertebrates, plants and fungi, which are less tested than birds and mammals, Conservation Charity Birdlife International Chief Scientist Stuart Butchart said.
“The confirmation of extinction is very complex because it takes confidence that the last species of the species died: it is harder for species that we understand their distribution, habitat, ecology and behavior less well,” said Butchart, who is also a researcher at the University of Cambridge at the Department of Zoology.
He called the question of whether the sixth mass extinction was approaching distraction, saying that the current percentage of extinction is of great concern and is on a scale that threatens people’s livelihood and well -being.
“Mass disappearance occurs very quickly in geological time, but it still takes tens of thousands to several million years,” he added.
“It is therefore very difficult to know whether the beginning of another mass extinction event for the last few decades or centuries.”
To get more CNN news and newsletters, create an account on cnn.com