I believe that souls are tiny pieces of the universal energy that flows through everyone, every thing, etc. When someone dies, that energy doesn't disappear (energy can be changed, not destroyed, etc.) it transfers to something else. From the universal energy, though, I think that as the population increases, more pieces of that energy come to be embodied by people. I also believe that that the energy from all things can be "reincarnated" into other things or species (ex. the energy from dead trees, other plants, animals, etc. might also be embodied by people), because it's all the same kind of energy, from the same source, just in different levels (a person would have more than a beetle, etc.). The energy doesn't grow or lessen, it's just distributed differently and as species become extinct, their energy could pass into other living things/new species.
at 12:23 AM on Jul. 6, 2012