Von Bertalanffy (1952) characterized the evolution of complex systems in terms of four major attributes:

Progressive integration (entails the development of integrative linkages between different species of biota and between biota, habitat, and climate)

Progressive differentiation (progressive specialization as systems evolve biotic diversity to take advantage of abilities to partition resources more finely, and so forth)

Progressive mechanization (covers the growing number of feedbacks and regulation mechanisms)

Progressive centralization (probably does not refer to a centralization in the political meaning, as ecosystems are characterized by short and fast feedbacks and decentralized control, but to the more developed cooperation among the organisms [the Gaia effect] and the growing adaptation to all other components in the ecosystem)