It is common understanding that it is usually a meteorite striking the Earth or a violent volcanic eruption that have caused most of Earth’s mass extinctions. But one study from Vanderbilt University has suggested that the first mass extinction in Earth’s history, which occurred about 540 million years ago, was not caused by one single violent event. Rather, evolution caused it, according to Science Daily.
Scientists have asserted that about 60 million years ago, a group of what we would now call animals, such as vertebrates, mollusks, sponges and jellyfish, wiped out what are known as Ediacarans, or complex, multicellular microorganisms, that were able to photosynthesize, drawing in sunlight for energy, according to The Week. These Ediacarans first took over the Earth about 600 million years ago, beginning an era scientists call the “Garden of Ediacara,” a peaceful era considering Ediacarans didn’t have to eat anything to survive.
When these microorganisms began developing, that is where the problems started: The developed animals that started to eat the Ediacara left, causing the first mass extinction, scientists said.
"There is a powerful analogy between the Earth's first mass extinction and what is happening today," Simon Darroch, assistant professor of earth and environmental sciences at Vanderbilt University, told Science Daily. "The end-Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and we are the most powerful 'ecosystem engineers' ever known."
Ediacarians developed from less complex microorganisms, which reigned on the Earth for more than 3 billion years, according to the Daily Mail. Some of these microorganisms then developed into Ediacara when they figured out how to use light for energy, which created a very toxic byproduct at the time: Oxygen. Because the Earth had been devoid of oxygen before Ediacara, most of the microorganisms the Ediacara developed from died off.
— Phys.org (@physorg_com) September 2, 2015
“This study provides the first quantitative palaeoecological evidence to suggest that evolutionary innovation, ecosystem engineering and biological interactions may have ultimately caused the first mass extinction of complex life," Darroch said.