Since I'm an Astrobiologist, here's the long version. Scenario 1: If an alien civilization came to destroy us for harvesting; iron for example. Our future would largely depend on the magnitude of industrious harvesting, because of atmospheric conditions and resource amounts after harvesting. 10,000 or so years later, again depending on conditions, we would have possibly de-evolved or physically degraded to match the environmental requirements. Some hundred years later, we would have re invented similar technologies, but our species would look and think vastly more different. If the harvesting was too high of a magnitude, we would die out. Scenario 2: If an environmental disaster took place, It would again depend on magnitude. Similar events would take place. If this helped, I'm glad it did! PM me if you have any questions. Remember, this is official! I actually study topics similar to this!