Silurian Hypothesis

The Silurian hypothesis is a theory proposed by a group of researchers in 2018 that suggests that complex life on earth may have evolved much earlier than previously thought. The hypothesis is based on the idea that the conditions that are necessary for life to arise may be common throughout the universe, and that it is possible that life on earth may have originated from a different celestial body before evolving and adapting to the conditions on earth. However, it should be noted that this is just a hypothesis and there is currently no concrete evidence to support it.

image credit: Paris Review

According to this hypothesis, the first complex, multicellular organisms may have emerged during the Silurian period, which occurred about 443 to 416 million years ago. This is significantly earlier than the generally accepted timeline for the evolution of complex life, which places the emergence of such organisms during the Cambrian period, about 541 to 485 million years ago. 

According to this hypothesis, the earth's ecosystems were much more diverse during the Silurian period than they are today, and many of the intermediate forms that existed during this time may have been specialised and adapted to specific ecological niches. As a result, these intermediate forms may have had a low probability of fossilisation, and their fossils may be difficult to find.

However, it is important to note that the Silurian hypothesis is not widely accepted by the scientific community and is still considered a controversial theory.