A long-held model of evolution suggests that intelligent life is extremely rare and unlikely to have evolved on Earth. However, a team of experts proposes an alternative view that challenges this notion. According to their research, the coevolution of life and Earth’s surface environment may have made the emergence of human-like intelligence more predictable than previously thought.
The hard-steps model, proposed by physicist Brandon Carter in 1983, suggests that intelligent life typically arises very quickly on planets or takes trillions of years to form. However, this view has been widely criticized for its unrealistic assumptions. The experts argue that instead of being rare, human-like intelligence may have evolved more frequently than previously thought.
The team proposes that the origin of eukaryotic cells, a fundamental innovation for life as we know it, occurred only once in Earth’s history. This conclusion is based on the tree of life, which shows all eukaryotic life branching off from a single line. However, other experts argue that this pattern could be explained by information loss due to extinction and the incompleteness of the fossil record.
Environmental evolution also plays a crucial role in understanding why human-like intelligence may have emerged when it did. The team suggests that as Earth changed physically and chemically over time, its surface conditions allowed for greater diversity of habitats for life. This change operated on geologic timescales, making it possible for human-like intelligence to evolve when it did.
The proposed new perspective has significant implications for the search for extraterrestrial intelligence. If human-like intelligence is more probable than previously thought, researchers are more likely to find evidence of intelligent life elsewhere in the universe. By combining insights from paleontology, biology, and astronomy, scientists can better understand the probability of intelligent life evolving on Earth and beyond.
Source: https://theconversation.com/evolving-intelligent-life-took-billions-of-years-but-it-may-not-have-been-as-unlikely-as-many-scientists-predicted-249114