Oxygen is one of the major components required for life to flourish and evolve on the earth. Lack of sufficient levels of oxygen in the atmosphere could undoubtedly, affect both the survival and evolution of life.
It is believed that animals first appeared around 600 to 700 million years ago, and now, a team of researchers have found that the oxygen levels during those periods measured just around 0.1 percent of that found today.
“In other words, Earth’s atmosphere couldn’t have supported a diversity of creatures, no matter what genetic advancement were in place,” said Timothy W. Lyons, co-author of the study and a distinguished professor of biogeochemistry in the University of California’s department of earth sciences.
The role of oxygen in the appearance of animals and their overall development has been a subject of attention among many scientists.
“Of course we already knew that all animals needed high oxygen levels in order to evolve,” said Noah Planavsky, lead author of the study and assistant professor of geology at Yale. “The really significant thing we found is that during this waiting period, oxygen levels were really low — lower than traditionally thought, and low enough that animals couldn’t have evolved and diversified.”
The researchers believed that the diversification of animals occurred as soon as the oxygen levels in the atmosphere started to go up. The team analysed the chromium levels present in the rock sediments from Australia, China, Canada and the US to gain a better understanding of the amount of oxygen that could have been present millions of years ago.
Their findings reveal that around 800 million years ago, there was a change in the chemical components of rocks, during which time, the oxygen levels started to increase rapidly.
“The authors have been very careful about which samples they have chosen to analyze — focusing on the same type of samples from similar settings across Earth history,” says Simon Poulton, a geochemist at the University of Leeds. “If correct, the very low levels of oxygen found in this study would have provided a major restriction on early animal evolution, thus suggesting that it was indeed a rise in oxygen that ultimately stimulated the evolution of our earliest animal ancestors.”
The researchers admit that more data is needed to support the fact that oxygen plays a key role in the boom in the diversity of animals on the Earth.
The findings of the study are published in the journal Science.