Researchers look back further in time to mass extinctions
Earth is in the midst of a mass extinction, losing thousands of species each year, but according to new research, the first such event, caused by environmental changes, happened far earlier than previously thought.
Most people are familiar with the disappearance of the dinosaurs some 66 million years ago, while about 250 million years ago another mass extinction took place.
Now, new research has revealed that as far back as 550 million years ago, another such event occurred.
Published in the Proceedings of the National Academy of Science and uncovered by researchers at the University of California and Virginia Tech, the research paper says the “percentage of organisms lost is similar to these other events, including the current, ongoing one”.
The researchers assert that about 80% of all species from the era, Ediacaran, were lost and were the first complex multicellular forms of life on the planet.
“We suspected such an event, but to prove it we had to assemble a massive database of evidence,” said Rachel Surprenant, University of California paleo-ecologist and study co-author.
The team documented nearly every known Ediacaran animal’s environment, body size, diet, ability to move and habits.
“We can see the animals’ spatial distribution over time, so we know they didn’t just move elsewhere or get eaten — they died out,” say the researchers.
“We’ve shown a true decrease in the abundance of organisms.”
They tracked creatures’ surface area to volume ratios, a measurement that suggests declining oxygen levels were to blame for the deaths.
“If an organism has a higher ratio, it can get more nutrients, and the bodies of the animals that did live into the next era were adapted in this way,” they say, adding. “Nothing is immune to extinction. We can see the impact of climate change on ecosystems and should note the devastating effects as we plan for the future.”
But, according to the World Wildlife Fund, the current mass extinction is unlike any before it. It is not driven by natural phenomena but by human activity, “primarily (though not limited to) unsustainable use of land, water and energy, and climate change”.
According to the Living Planet Report, 30% of all land that sustains biodiversity has been converted for food production.
Agriculture is responsible for 80% of global deforestation and accounts for 70% of the planet’s freshwater use, devastating the species that inhabit those places by significantly altering their habitats.
“It’s evident that where and how food is produced is one of the biggest human-caused threats to species extinction and our ecosystems.
“To make matters worse, unsustainable food production and consumption are significant contributors to greenhouse gas emissions that are causing atmospheric temperatures to rise, wreaking havoc across the globe,” according to experts at WWF.