地球上複雜的生命可能比想像的古老得多

A team of scientists has recently made a groundbreaking discovery that could significantly alter our understanding of the timeline of complex life on Earth. They propose that complex life forms, which include animals, may have originated as much as 2. 1 billion years ago, which is a staggering 1. 5 billion years earlier than the widely accepted belief that animal life began around 635 million years ago. This research was conducted in Gabon, a country located in Central Africa, where the scientists found compelling evidence embedded deep within ancient rocks. These findings suggest that the environmental conditions necessary for the existence of animal life were present 2. 1 billion years ago. However, the researchers also noted that these early life forms were confined to a specific area, an inland sea, and did not spread across the globe. Ultimately, these organisms became extinct, which raises intriguing questions about the history of life on our planet. This new perspective represents a significant departure from traditional scientific thought, and not all experts are in agreement with these findings. Most scientists have long believed that the emergence of animal life occurred around 635 million years ago. The research adds to an ongoing debate regarding the nature of certain unexplained formations found in Franceville, Gabon, which some researchers argue may be fossils. To investigate this further, the scientists examined the rock surrounding these formations to determine if it contained essential nutrients such as oxygen and phosphorus, which are critical for supporting life. Professor Ernest Chi Fru from Cardiff University was part of the international team that conducted this research. He shared with BBC News that if their theory holds true, these ancient life forms would have resembled slime mould, a simple organism that lacks a brain and reproduces through spores. However, not all scientists are convinced by this new theory. Professor Graham Shields from University College London, who was not involved in the research, expressed some skepticism. He stated, 'I'm not against the idea that there were higher nutrients 2. 1 billion years ago, but I'm not convinced that this could lead to diversification to form complex life. ' He emphasized the need for more substantial evidence to support these claims. Professor Chi Fru, on the other hand, believes that their work provides valuable insights into the processes that led to the emergence of life on Earth. He stated, 'We're saying, look, there's fossils here, there's oxygen, it's stimulated the appearance of the first complex living organisms. ' He further explained that their findings help to reinforce our understanding of the origins of life and where we all come from. An artist's impression of what life might have looked like 2. 1 billion years ago depicts jellyfish-like creatures swimming in a shallow sea, providing a visual representation of this ancient ecosystem. The initial suggestion that complex life could have begun earlier than previously thought emerged about a decade ago with the discovery of the Francevillian formation. Professor Chi Fru and his colleagues believe that this formation consists of fossils that indicate the presence of life capable of movement. However, these findings have not been universally accepted within the scientific community. To gather more evidence to support their theories, Professor Chi Fru and his team analyzed sediment cores, which are samples taken from the rock in Gabon. The chemical analysis of these rocks revealed that a 'laboratory' for life was created just before the formation appeared. They theorize that the high levels of oxygen and phosphorus were generated by the collision of two continental plates beneath the ocean, resulting in volcanic activity. This geological event isolated a section of water from the oceans, creating a nutrient-rich shallow marine inland sea. Professor Chi Fru explained that this protected environment facilitated photosynthesis, leading to a significant increase in oxygen levels in the water. He stated, 'This would have provided sufficient energy to promote increases in body size and greater complex behavior observed in primitive, simple animal-like life forms such as those found in the fossils from this period. ' However, he also cautioned that this isolated environment ultimately contributed to the extinction of these life forms due to a lack of new nutrients to sustain a food supply. Elias Rugen, a PhD student at the Natural History Museum who was not involved in the research, expressed agreement with some of the findings. He noted that it is evident that 'oceanic carbon, nitrogen, iron, and phosphorus cycles were all doing something a little bit unprecedented at this point in Earth’s history. ' He added that there is no reason to dismiss the possibility that complex biological life could have emerged and thrived as far back as 2 billion years ago, but he reiterated the need for more evidence to substantiate these theories.