The first law of thermodynamics states energy can be transformed, but cannot be created or destroyed. We contain a bit of energy from every life that came before us and we will contribute a bit to every life that comes after, across not just our world but all the worlds in all the universes that will ever exist. (Hopefully the bit of Bieber or Cyrus that make their way into my next life will be off-set by something from Da Vinci or Einstein.) Oh, and this is also why calories not burned during exercise go right to your hips.
