The easiest way to do this is on Isla Nublar, which you unlock after getting three stars on the first island, so you can get this achievement pretty early on. Isla Nublar has unlimited funds, so if you have the island unlocked it should only take about ten minutes maximum. You can close the park and you don't even need to worry about fences, just have your creation centers out in the open. I built three and connected them to the grid and just spammed cheap and fast herbivores (gallimimus, struthiomimus) until it popped.