Structurally modern terrestrial ecosystems originated approximately 380–340 million years ago (Ma) from the Middle Devonian Period through the earliest Carboniferous. Although on different temporal and spatial scales, the evolutionary assembly of these ecosystems parallels the assembly of modern ecosystems following major disturbances or recovery from widespread physical and climatic disruptions, such as the end of the last glaciation. The deep evolutionary history of terrestrial ecosystems documents the emergence of constraints that would affect all subsequent ecological dynamics and dictate the nature of smaller-scale landscape and successional patterns. The fossil record is the sole source of information about the establishment of these basic patterns of species interaction and resource partitioning.