Would we have evolved in the same way if some creatures never went extinct? (like dinosaurs)

Question: Would we have evolved in the same way if some creatures never went extinct? (like dinosaurs)
- Keywords:
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  evolution
  
  extinction
Asked by Dr Sibley to John, Laura, Luke, Rob, Ruth on 15 Jun 2016.
- John Fossey answered on 15 Jun 2016:
  
  No – any change in the ecosystem changes evolutionary pressure
- Laura Finney answered on 15 Jun 2016:
  
  probably not. If the dinosaurs had not become extinct then we would probably not have risen to the top of the food chain and I think this would have had huge consequences for us. It would have at least slowed our evolution down.
- Luke Williams answered on 16 Jun 2016:
  
  There is increasing evidence that mammals were already taking over the landscape before the dinosaurs went extinct, but as has already been said, any small change could have had a profound effect. It is quite possible that even with changes that we may have ended up similar, but there’s also no guarantee that would happen at all, or even if it did, that things might not have taken millions of years longer or shorter.
  
  The very nice metaphor for this is the butterfly effect: https://en.wikipedia.org/wiki/Butterfly_effect

Question: Would we have evolved in the same way if some creatures never went extinct? (like dinosaurs)