Affiliate Marketing Secrets

I’m reading the beak of the finch and I just got done reading it. There’s a quote that says…
“Chimpanzees in the last day of the African rain forests are teaching their children how to crack nuts with stones. They are taking the kinds of halting,modest steps that might, if favored, if selected for many generations, carry them on a path toward something like our niche. Watching them, human observers notice striking variations in intelligence from individual to individual. Where there is genetic variation, there is room for selection and evolution. Probably in every line of primates there are a few, like Imo on her island, who could lead their kind in our direction. But at the moment of course that path is blocked. The thinking niche is taken, at least for the moment.”
I don’t understand what the few lines mean. If anyone knows, please tell me what it means esp the the thinking niche is taken…