It is pretty hard to give levels of importance to factors that trigger an extinction. However, the shorter your lifespan and the larger the number of your progeny gives a species more chances to collect mutations that allow the given species to survive environmental change besides that the sheer number of members in a species also make it harder to wipe out. It is clearly seen in the fact that bacteria are the most successful organisms ever and arguably the last ones to disappear at the end of life on planet earth. In fact, the planet belongs to the bacteria. They are inside every other organism, it very gram of soil or water, inside the earth up to several km deep and in the deepest ocean basins.