How to Build an Ecosystem: Early Animals of the Ediacaran and the Emergence of the Tangled Bank

The early animal communities of the Ediacaran (∼580–539 Mya) provide novel insights into how the modern biosphere operates by recording the initial ecological framework from which ecological interactions first built up. These Ediacaran communities do not have direct counterparts because they are soft-bodied, largely heterotrophic, and predator free. However, the exceptional preservation of immobile, benthic Ediacaran animals enables the resolution of their community dynamics to similar levels to those of extant benthic systems. While many of the key processes shaping the modern benthos were present in early benthic communities, the diversity of ecological interactions within communities, and the variability of these interactions through time and space, was notably simpler than that found today. In the Ediacaran, ecosystem dynamics and complexity started with reproduction and dispersal, with adaptations and responses to the environment a secondary effect, followed by direct biotic interactions. As these biotic interactions became dominant, coevolution established a tangled bank of complexity.