Objectives: 1. Use Charnov’s dimensionless life history traits to visualize and quantify the life history strategies of amniotes. 2. Compare life history strategies of birds, mammals, reptiles, and smaller clades by using hypervolumes. 3. Investigate if these so-called invariant traits are actually invariant with body mass. 4. Analyze the macroevolutionary patterns of the dimensionless traits and their components between clades.