During the first four billion of its existence, our planet was devoid of any life except microbes. The situation radically changed at a time when plants began to plant the Earth, creating a favorable environment for the settling of the continents by animals. Previously, scientists believed that it happened about 420 million years ago, based on the fossils found by them fossil plants. But the new findings made them change their minds.
New research published in the Proceedings of the National Academy of Sciences (Proceedings of the National Academy of Sciences) proves that the colonization of the Earth's surface by plants occurred 100,000,000 years earlier than previously thought. And this discovery seriously changes the perception of the evolution of the biosphere of our planet by science. After all, plants are one of the key factors in the carbon cycle that regulates the atmosphere and climate of the planet for hundreds of millions of years.
A team of researchers from the School of Earth Sciences at Bristol University used the technology of "molecular clocks" – a method for dating phylogenetic events, based on the hypothesis that evolutionarily significant changes in monomers in nucleic acids or amino acids in proteins occur at a practically 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 led to an increase in the parameters of continental weathering (the process of destruction and chemical alteration of rocks). All this ultimately led to a sharp decline in the level of carbon dioxide in the atmosphere and to global cooling. Previous attempts to simulate these changes in the atmosphere were inaccurate. Our studies introduce some corrections into the already existing model of the evolution of the biosphere, "the author of the study, Dr. Jennifer Morris, shares her thoughts.