The paper traces evolution through repeated execution of a system’s operational cycle — a morphodynamic cycle comprising exogenous effects of the environment on the system, endogenous changes in the system, and exosomatic system actions on the environment. Repetition of this cycle produces structural and functional changes in both the system and its environment. Accumulated changes give rise to persistence ratchets: cumulative reshaping of viable state space that becomes increasingly costly to reverse. This substrate-agnostic causal framework of morphodynamic cycle and persistence ratchet is applied to interpret eight evolutionary transitions across cellular and organismal scales, from extremophiles to humans. The paper sketches contours of future human evolution through continuing directional accumulation of system and environmental complexity via endosomatization and exosomatization.
Hari Harikrishnan (Sat,) studied this question.