So far, scientists generally believe that animals first appeared on Earth 635 million years ago. But an international research team led by British scientists has discovered evidence of an earlier ecosystem that may have existed about 2.1 billion years ago in the French Villian Basin near Gabon on the Atlantic coast of Central Africa. This discovery suggests that complex life on Earth may have emerged about 1.5 billion years earlier than previously thought. The relevant paper was published in the latest issue of the journal "Pre Cambrian Research". The main author of the latest paper, Dr. Ernest Qi Furu from the School of Earth and Environmental Sciences at Cardiff University in the UK, pointed out that the increase in phosphorus and oxygen concentrations in the ocean is related to a biological evolutionary event about 635 million years ago. In the latest study, they conducted geochemical analysis on marine sedimentary rocks in the Franconian Basin approximately 2.1 billion years ago and discovered the first environmental evidence of complex life evolution on Earth. Previously, scientists have not reached a broad consensus on whether the fossil body here is a large biological fossil body. The research team believes that the collision and merger of Congo and the San Francisco craton (a stable landmass formed during the pre Cambrian period) resulted in unique and rich underwater volcanic activity. These activities limit or even cut off the connection between this part of the water and the global ocean, forming a nutrient rich shallow inland sea and creating a nutrient rich 'laboratory' for the evolution of complex organisms. In this local environment, the photosynthesis of blue-green algae has been active for a long time, leading to the oxidation of local seawater and the production of a large amount of food resources. These photosynthesis and food resources provide sufficient energy, leading to an increase in animal size and the emergence of more complex behaviors observed in primitive, simple animal like life forms. However, the isolation of this water area, as well as the harsh environment surrounding it, may hinder the spread of complex life forms that have emerged here globally. Frou pointed out that their observations suggest that complex life on Earth may have evolved in two stages. The first time was after a significant increase in atmospheric oxygen levels 2.1 billion years ago; The second time was about 1.5 billion years after the second increase in atmospheric oxygen content. Although the first generation of complex life did not blossom globally, the second evolution created the animal diversity we see on Earth today. (New Society)