The Earth is currently in the midst of a mass extinction, with thousands of species being lost each year. A new study suggests that environmental change triggered the first such event in history, and it happened millions of years earlier than scientists had previously realized.
Most dinosaurs famously disappeared at the end of the Cretaceous period 66 million years ago. Before that, most of Earth’s life disappeared during the Permian and Triassic periods, about 252 million years ago.
Thanks to the efforts of researchers at Caltech Riverside and Virginia Tech, we now know that a similar extinction occurred during the Ediacaran period 550 million years ago. The discovery is listed in the Proceedings of the National Academy of Sciences.
Whether this represents a true ‘mass extinction’ is unknown, but the rate of organisms lost is similar to these other events, including the ongoing one.
Researchers believe that environmental change is responsible for the loss of about 80% of the Ediacaran organisms, the first complex multicellular lifeforms on Earth.
“The geological record shows that the world’s oceans lost a lot of oxygen during that time, and the few surviving species had bodies adapted to low-oxygen environments,” says UCR’s Old School. Chenyi Tu, an ecologist and study co-author, said.
This earliest was more difficult to document because, unlike later events, the dead creatures were soft-bodied and poorly preserved in the fossil record.
UCR paleoecologist and study co-author Rachel Surprenant said: The team documented the environment, body size, diet, athletic performance, and habits of nearly every known Ediacaran animal.
With this project, researchers sought to disprove claims that the massive loss of animal life at the end of the Ediacaran period was something other than extinction. Previously, some believed that the event could be explained by a lack of adequate data collection or changes in animal behavior such as the arrival of predators.
“Being able to see the spatial distribution of animals over time, we can see that they have gone extinct, not just moved to another location or been eaten,” says Chenyi. “We have shown that the numbers of organisms are truly declining.”
They also tracked the creature’s surface-to-volume ratio. This reading suggests that low oxygen levels are the cause of death. “If an organism had a higher ratio, it could get more nutrients, and the bodies of animals that lived in the next era adapted in this way,” says UCR paleoecologist Heather McCandless. Research co-author.
The project grew out of a graduate class led by UCR paleoecologist Mary Droser and her former graduate student, Scott Evans, who is now at Virginia Tech. In the next lesson, students will investigate the origin of these animals rather than their extinction.
Ediacaran creatures would be considered bizarre by today’s standards. Many of the animals were able to move, but unlike those living today. Among them are his Obamus Coronatus, a disc-shaped creature named after the former president, and his small egg-shaped raisin-like creature, named after British naturalist Sir David Attenborough. of Attenborites janeae were included.
“These animals were the first evolutionary experiments on Earth, but they only lasted about 10 million years. Evolutionarily speaking, not that long,” Droser said.
It is not clear why oxygen levels dropped sharply at the end of the era, but it is clear that environmental changes can destabilize and destroy life on Earth at any moment. It has caused all mass extinctions, including those that are happening.
Phillip Boan, a geologist at the University of California, Riverside and study co-author, said:
“Nothing is immune to extinction. The impact of climate change on ecosystems is clear, and we need to be mindful of the devastating effects when planning for the future,” said Boan. I’m here.