Detailed records of change within individual species show that although characters commonly remain relatively unchanged for long periods, when changes do occur they are rapid, separated by long periods of very little change. this observation is consistent with

It is consistent with Punctuated equilibrium. A theory that states that when a species show up in the fossil record they will turn into a stable record, showing almost zero evolutionary change through their geological history. When the species do change, this change is rapid and split the species into tow rather than make the original species evolve into another one.