> Reaching “only” the Neolithic stage could be described as a “Silurian hypothesis light”; it’s not highly significant achievement for a species, and even such a species can significantly turn over the planet’s fauna. Even our hunter-gathering (Paleolithic) ancestors hunted a number of large animal species to extinction (you don’t have to kill every last mammoth or giant bird to do that), and our farming ancestors (before the advent of even the simple most metal tools) caused massive modifications of the fauna and florae of extensive landscapes. Some of these faunal changes might be detectable millions of years into the future.
To be fair, a species can achieve that without any intelligence or civilization whatsoever if they just manage to grow their population enough.
I think the most extreme species in that regard would be cyanobacteria, which changed the composition of Earth's atmosphere from methane and CO2 to oxygen [1] - and subsequently caused the metabolism of almost all other species to become oxygen-based.
This change is not just "detectable" today, it became the basis of most life on the planet.
Another one is the Azolla event hypothesis where a variety of fern grew so much that as it died and sank to the ocean it sequestered massive amounts of carbon, enough to alter the climate.
To be fair, a species can achieve that without any intelligence or civilization whatsoever if they just manage to grow their population enough.
I think the most extreme species in that regard would be cyanobacteria, which changed the composition of Earth's atmosphere from methane and CO2 to oxygen [1] - and subsequently caused the metabolism of almost all other species to become oxygen-based.
This change is not just "detectable" today, it became the basis of most life on the planet.
[1] https://asm.org/articles/2022/february/the-great-oxidation-e...