Ecological communities are very complex systems comprising species that interact with each other in spatially extensive settings. Understanding the rules that govern these systems and how they behave in time is fundamental, but it is also of practical importance since it concerns the maintenance of biodiversity in the face of global change. In this talk I combine results from experiments in manipulable communities of small animals and microorganisms with math modeling, and large scale analyses of functional trait information to advance our understanding of the organizational principles linking ecosystems across scales: from individuals’ traits, to the assembly of ecological networks, and the emergence of macroscopic spatial patterns. These findings contribute insights into how local and spatial dynamics interact to influence large scale properties of ecosystems. But they also lead to new questions about the rules of life, highlighting the strong need for a refinement of theoretical methods, more large scale field observations, and creative laboratory experiments that leverage modern technologies.