Internal causes of extinction are to be found in exaggeration of body size, in the hypertrophy or over-specialization of certain organs, in the irreversibility of evolution, and possibly, although this has not been demonstrated, in a progressive reduction of variability.
This is often read aloud and the irreversibility of the contract is symbolized by the breaking of a plate.
Gender constancy has been defined as children's understanding of the irreversibility of their sex, which develops in stages between about the ages of two and seven years.
This irreversibility is due to the work required to evolve bubbles of gas at the surface of bright platinum plates.
