While searching for the answer of what actually led to the evolution of animals, researchers have revealed that it was the rise in oxygen level that kick-started the evolutionary process and made the highly advanced and complex animals including humans of today. However, the oxygen didn’t rise instantly and it took nearly 100 million years for oxygen to reach a certain level so that it can support evolutionary process.
“We wanted to find out how the evolution of life links to the evolution of our climate,” said lead researcher Philip Pogge von Strandmann from the University College London (UCL).
For the study, researchers tried to evaluate what happened to global oxygen levels 770 – 520 million years ago on the Earth. For this, study authors took the help of new technique and examined the amount of selenium isotopes present in the rocks. What researchers found was mind boggling. It was found that oxygen level rose significantly over a time span of 100 million years that led to the evolution of animals. Once, oxygen was only 1 percent of today’s global oxygen level which climbed up to 10 percent after 100 million years.
Researchers believe that it was the most significant hike in oxygen levels in entire history of Earth’s climate and its effect is visible till today. “We were surprised to see how long it took Earth to produce oxygen and our findings dispel theories that it was a quick process caused by a change in animal behaviour,” added Strandmann.
Earlier, it wasn’t clear whether oxygen level kick started the evolutionary process or animals evolved before oxygen started to rise. However, the new study has neatly drawn a blueprint of what actually happened nearly 600 millions years ago when first of the evolved species appeared on the Earth.