During the first four billion of its existence, our planet was devoid of any life except microbes. The situation changed radically at the moment when the earth began to be planted with plants, which created a favorable environment for the colonization of continents by animals. Previously, scientists believed that this happened about 420 million years ago, relying on the fossils of fossil plants they found. But new finds made them change their minds.
New research, published in the journal Proceedings of the National Academy of Sciences, proves that plant colonization of the Earth's surface occurred 100,000,000 years earlier than previously thought. And this discovery seriously changes the perception by science of the evolution of the biosphere of our planet. Plants are one of the key factors in the carbon cycle, regulating the atmosphere and climate of the planet for hundreds of millions of years.
A team of researchers at the University of Bristol's School of Earth Sciences used molecular clock technology, a method for dating phylogenetic events based on the hypothesis that evolutionarily significant monomer substitutions in nucleic acids or amino acids in proteins occur at an almost constant rate. Thus, it became clear to scientists that the first terrestrial plants existed on Earth already in the middle of the Cambrian period, which began 541 million years ago.
“The global spread of plants and their adaptation to life on land have led to an increase in indicators of continental weathering (the process of destruction and chemical alteration of rocks). All this ultimately led to a sharp decrease in the level of carbon dioxide in the atmosphere and to a global cooling. Previous attempts to model these changes in the atmosphere have proven inaccurate. Our research makes some adjustments to the already existing model of the evolution of the biosphere,”- the author of the study, Dr. Jennifer Morris, shares her thoughts.
Sergey Gray