>it was common knowledge among middle age that Earth was flat. doesn't seem an argument to me
And you don't seem to know basic history, casting doubt on other things you say. Nobody serious in the middle ages (or since much further back than that either) thought seriously that the Earth was flat.
actually i meant "geocentrism" but it was too late to edit but you are right, middle age didn't thought Earth was flat
now if you are defending this absurd commentary that Amazonia was a grassland 10,000 years ago and turned out to be what's because humans, i think you both are on the level of flat earth 21° century people
No, not defending that, since evidence points to it having been a forest, but that a place like the Amazon could form from grassland in the span of a few thousand years is absolutely possible.
the western part once turned into a huge wetland, after the Andes emerged from the ocean. that was more than 10 Ma ago although. that was also what made the western Amazonia part differ on its biodivesity
humans may altered the biodiversity of Amazonia by breeding only wanted species. but we don't have too much evidence of that (yet). but if it was, the biodiversity of pre-humans was probably richer, as indigenous apparently managed the forests with fire and farmed hyperdominant cultures [0]
And you don't seem to know basic history, casting doubt on other things you say. Nobody serious in the middle ages (or since much further back than that either) thought seriously that the Earth was flat.