The majestic blue whale has almost carried the sea 4.5 million years, While Neanderthals Out of existence in a few thousand years. But are those creatures representative of the species as a whole? How long does it take for a species to become extinct?
The answer we get now may be very different than usual. Due to the destruction of the dwelling, Climate change, And other factors, the range of plants and animals, are disappearing from the planet faster than all the other five points of history. Some experts say we are in this Sixth mass extinction Event. But even in the quietest period of Earth’s history, the answer varies depending on the type of species you are looking at. For mammals, the average species has lived for 1 million to 2 million years, according to an article in the journal People and the planet.
However, this average does not occur during all geographical periods and for all mammals. Average for Cenozoic era (Million 65 million years ago today) Mammals are 21.5 million years old, with larger mammals surviving longer than smaller mammals, according to a 2013 study in the journal 2013 Integrated Zoology. For reckless species, the period is more dominant; They live an average of 5 million to 10 million years.
Related: What is the first human species to become extinct?
However, this number is controversial. Experts do not agree on the average time of a breed falling into any category before extinction. Fossil record documents when a species shows up and when it disappears, but it leaves a huge margin of error because conditions must be right for this To form fossils, And those conditions are not always the same when a race shows up and blinks. And these lifetime statistics are not that useful. Stuart Pimme, a leading extinction expert and conservation ecologist at Duke University’s Nicholas School of the Environment, said he prefers to think about extinction in terms of how many species die each day, month or year.
“It’s easier to think in terms of mortality, mostly because there are some species that really live longer,” Pimme said. “And then there are other species that are short-lived. And the average won’t help as much as you think.”
The mortality rate of this species, also called background extinction rate, is also controversial. Pimme put a historic historical number – a figure that covers mass time, excluding mass extinctions – about one species per 1 million species per year. This means that if there were a million species on the planet, one would be extinct every year. (For comparison, there are about 7.7 million species on the planet today, according to a study in the journal PLOS Biology.) Nevertheless, other experts estimate that the species dies at a rate of 0.1 species per million per year and still others die at the rate of two species per million per year, according to a research article in the journal Science progress.
The current extinction rate is much higher than predicted about the past – PIMM’s background is about 1,000 times higher than the estimated extinction rate, he said. However, Tierra Currie, a senior scientist at the Center for Biological Diversity in Oregon, said that not everyone agrees on how species are now becoming extinct. Some experts estimate that the current extinction rate is only 100 times faster or 10,000 times faster at other extremes.
There are many reasons why current extinction rate estimates vary. “The extinction rate depends on how many species there are on Earth and how fast they are becoming extinct,” Curry said. “And really no one knows the answer to any of them.” Pimme added that about 90% of the living species – mostly insects – are anonymous. And if researchers do not know that a species exists, they do not know that it is extinct. Another complication is that it can be difficult to tell when a species is dead. Just because researchers haven’t seen them in many years doesn’t mean they’ve gone for good. Species are endangered in the wild, but calculations can be more difficult when living in a zoo.
One thing that experts agree on is that the rate of modern extinction is very high. “Species are adapting as fast as they can,” Pimme said. “But eventually luck ends and they don’t adapt enough. And they go.”
Published on Original Living Science.
