Grand challenges in population dynamics

Most multicellular organisms (either metazoan or plants) are grouped in contiguous spatial distributions, where they share genes and common environmental features. These aggregations—the size of which fluctuates in space and time— are called populations. Despite the fact that population dynamics has historically attracted the interest of many scientists, we are still far from understanding how and why populations fluctuate in natural ecosystems. The main reason is that populations are complex systems, with emergent properties that are impossible to determine by the sum of their parts. The components of population dynamics, including processes and patterns, are numerous and have multifaceted dimensions. Here, I will highlight some of them—unavoidably, in a subjective manner.