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Wednesday 05 Oct 2022The Earth: evolution of a habitable planet

Andrew Watson - University of Exeter

LSI Room B ? 14:00-15:00

Life was established on Earth very early and ever since, the surface environment has co-evolved with life. In particular, there have been a few traumatic climate near-disasters, triggered by biological innovations. These in turn seem to have paved the way for further fundamental evolutionary advances. The evolution of complex life has therefore been a truly planetary-scale phenomenon that required the transformation of the Earth in step with biological evolution. How likely is it that we might find evidence for something similar having taken place on an exoplanet? The rapid establishment of the bacterial biosphere on the Archean Earth suggests that we might find bio-signatures of such planets. However the subsequent transitions, which were necessary for us to be here on Earth, were probably very unlikely. I would predict therefore that we are unlikely to find evidence for any exoplanet hosting more complex life for example having an oxygen-dominated atmosphere.

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