Recently, scientists have discovered the Cambrian explosion, which has been significant in the journey of Earth, was likely to have occurred because of a small increase in oxygen levels.
A team of researchers used datasets from an international consortium of scientists which displayed modest changes in oxygen levels that are likely to have caused the evolutionary leap.
All about the Cambrian explosion
The Cambrian explosion took place nearly 540 million years ago and led to a rapid burst of evolution because of which the diversification of life occurred on the planet.
Earlier, life only comprised smaller multicellular and single-celled organisms on Earth. However, the fossil record shows that following the explosion, in 20 to 30 million years there were a variety of complex creatures which emerged on Earth.
Every new species was found to have a strange and novel body plan and had features like gripping appendages, mineralised shells, and sensory organs like eyes.
“The specific animals that we observe as fossils from rocks of this age may look weird and wonderful to us,” Dr Richard Stockey, lead author of the new study and a paleobiologist at the University of Southampton told IFLScience.
“But the ecological roles they were playing were very similar to marine animals that we know and love today,” he added.
“Unravelling whether there was an environmental trigger to this (geologically) rapid shift in the habitability of Earth’s oceans is a question that is fundamental to our understanding of our biosphere, and even potentially for the habitability of other planets,” the lead author said.
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Scientists have for decades carried this theory that the Cambrian explosion happened because of a sudden increase in atmospheric oxygen. However, they did not have sufficient evidence to back the case.
“As a community, we have been balancing a number of different lines of evidence, based on the chemical composition of ancient sediments,” Stockey said.
“Some of these seemed to indicate a big oxygenation event around the Cambrian explosion, while others seemed to indicate that this scale of oxygenation didn’t occur until around 140 million years later,” he added.
(With inputs from agencies)