Lost World: Evidence of Mass Animal Extinction Found
In a surprising revelation, researchers have discovered traces of previously unknown mass extinction incidents that preceded the five main ones that science knows.
This era of mass collapse, the Ediacaran, dates back to a period almost 550 million years ago. It suggests the biodiversity loss timeline could be more detailed than previously learned.
Virginia Tech paleobiologist Scott Evans and his team recently published their study. Their findings provide a glimpse into a world full of inhabitants that may seem alien to modern researchers.
The study delved into the long-time belief of a standard sampling bias in this era’s insufficiency of soft-bodied animal fossils. It was published in PNAS, confirming the known narrative of mass extinction incidents.
Scientists Uncovered Evidence of What Could Be Earth's First Mass Animal Extinction https://t.co/roIIpN7Iz8
— ScienceAlert (@ScienceAlert) May 10, 2023
Earth’s oceans teemed with diverse organisms back in the Ediacaran period. Most of them were soft-bodied, while others had a shell-like covering.
This early stage of the biological era saw unique life forms. Some organisms had similarities to today’s jellyfish and sponges. Others resembled standard plant fronds.
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However, the team’s collection of rare fossil records from this era proves a significant change in biodiversity. The data contradict the idea that the lack of soft-bodied organisms in the later Ediacaran period was due to preservation failure.
The Silent Mass Extinction
The research also indicates an overall increase in biodiversity from the early to middle stages of the Ediacaran, White Sea, and Avalon. This period witnessed an evolution in the feeding process, ecological connections, life habits, and body sizes.
In that era, smaller animals ate microbial mats on the sea surface, overpowering the previously dominant sessile filter feeders. However, Nama, the shift to the final stage of the Ediacaran, is witness to a catastrophic drop in biodiversity.
Almost 80% of creatures vanished, with just 14 of the 70 known groups surviving in the Nama era. These groups belong to the White Sea stage. The percentage of organisms lost is similar to the “Big 5” mass extinctions.
Survivors of this cataclysm were giant, frond-like creatures with high-surface to volumes proportions. These findings suggest an adjustment to a reduction of oceanic oxygen.
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The team cited, “High surface-area taxa would have been comparatively better adapted to survive in low-oxygen environments.” A 2018 study implying extensive ocean anoxia at the end of the Ediacaran supports this theory.
Overall, the scientists’ data undermines the connection between environmental change and Ediacaran’s shift. It shows a pattern crossing other major mass extinctions in history.
This study not only redefines our knowledge of the mass demise timelines but also reminds us of how environmental changes can trigger extreme biodiversity loss.
