The majestic blue whale has been in the sea around 4.5 million years, when Neanderthals Wink disappearing lasted hundreds of thousands of years. But do these organisms represent species as a whole? How long do species usually exist before they go extinct?
Turns out the answer we found now might be very different from usual. Because the habitat is destroyed, climate change, and a host of other factors, plants and animals are disappearing from the planet faster than all but possibly five other points in history. Some experts say we are in sixth mass extinction incident. But even during quieter periods of Earth’s history, the answers will vary depending on the type of species you̵7;re looking at. For mammals, the average species lasted between 1 million and 2 million years, according to an article in the magazine. People and planets.
However, this average does not hold for all geological periods and for all mammal species. Average level for Kainozoi era (65 million years ago to present) mammals are 3.21 million years old, with larger mammals lasting longer than smaller mammals, according to a 2013 study in the journal Integrated zoology. For invertebrates, timing was even more impressive; They last an average of 5 million to 10 million years.
Related: What was the first species humans led to extinction?
However, these numbers are controversial. Experts disagree on the average length of time that species of any type exist before extinction. The documentation records fossil when a species appears and when it disappears, but it leaves great error as the conditions must be perfect for fossil formationsand those conditions are not always present when a species arises and disappears. And these life span metrics are not as useful nonetheless. Stuart Pimm, leading expert on extinction and conservation ecologist at Nicholas School of Environment at Duke University, said he likes to think about extinction when how many species die on a daily, monthly or monthly basis. annual.
“It’s easier to think about… mortality, in large part because some species live so long,” Pimm said. “And then there are other species that have short lifespans. And the average doesn’t really help you as much as you think.”
The mortality rate of this species, known as the background extinction rate, is also controversial. Pimm has placed the historical number – an all-time number, excluding mass extinction – at about one species extinct per 1 million species per year. That means if there are a million species on the planet, one species will go extinct every year. (For comparison, there are about 8.7 million species on the planet today, according to a study in the journal PLOS BiologyHowever, other experts estimate that species usually die at a rate of 0.1 species per million per year and still others at two per million per year, according to a research paper in the journal. Scientific advance.
The current extinction rate is much higher than any predicted past – about 1,000 times more than Pimm’s background extinction estimate, he said. However, not everyone agrees on the rate at which species are now extinct, said Tierra Curry, a senior scientist at the Center for Biodiversity in Oregon. Some experts estimate that the current rate of extinction is only 100 times faster or at the other extreme, 10,000 times faster.
There are a number of reasons why estimates of the current rate of extinction differ. “The rate of extinction is based on the number of species on Earth and their rate of extinction,” said Curry. “And nobody really knows the answer to either of those questions.” About 90% of the living species – mostly insects – are probably unnamed, Pimm added. And if researchers don’t know that a species exists, they won’t know it’s extinct. Another complication is that it is difficult to know when species died. Just because researchers haven’t seen them for a few years doesn’t mean they’re gone. Calculation can become more difficult when species are extinct in the wild but live in zoos.
One thing experts agree is that the modern extinction rate is too high. “The species are adapting as quickly as possible,” says Pimm. “But in the end the luck ran out and they didn’t adapt quickly enough. And they left.”
Originally published on Live Science.