It’d be interesting to come back to earth in 50 million years after humans are long extinct and life in all its diversity has had some chance to recover.

What would be here then? Would cats and dogs, being so widespread now, evolve into myriad forms on every continent to fill ecological niches where we’ve caused animals to go extinct?

Would avians one again evolve fill ecological niches as they did after the dinosaur extinction 65 million years ago?

Maybe oxygen would increase greatly  due to lack of human influence and we’d have dragonflies with meter-long wingspans once more.