The Reference: Dr. Wu may be the only human to return from Jurassic Park, but he's not completely without shared company. The T-Rex who takes on the I-Rex is actually the same one that terrorised/saved Dr. Grant and the kids back in 1993. World's Tyrannosaurus has scars on her neck that match up with the claw marks left by the raptors at the end of Park, leading to much speculation that was eventually confirmed by none other than director Colin Trevorrow. What It Really Means: This being the same T-Rex doesn't just amp up the awesome factor of the final showdown, but is also the ultimate confirmation of "life finds a way." The dinosaurs in the original Jurassic Park were engineered with a lysine deficiency, meaning that without regular, manual doses they'd only survive a couple of days. It was finding a way around this plot point that led to the creation of Isla Sorna in the original sequels - it was the only conceivable way around issue without creating a major narrative hole. But, as the old girl's survived, it shows that wasn't the case; without humans around, she still managed to live the years between the evacuation of Isla Nublar and Masrani setting up Jurassic World.