Spencer’s Reviews > Worlds Hidden in Plain Sight: The Evolving Idea of Complexity at the Santa Fe Institute, 1984–2019 > Status Update

Each of the systems interacts with its environment in a game-like way...The environment typically exhibits a range of regularities or niches, that can be exploited by different action sequences or strategies....At all levels, the competitive interactions give rise to counterparts of the familiar interactions of population biology—symbiosis, parasitism, competitive exclusion, and the like.