How do biological populations respond to the impacts that humans have on them? For example, what will happen when we start to fish for a particular species of fish? How much of the fish can we catch before the entire population disappears and will the population recover from too much fishing? These are questions about exploiting biological populations that can only be answered satisfactorily if we understand which processes are responsible for the dynamics of the populations, i.e. the changes in the number and types of individuals making up the population. Most of our current ideas about how populations respond to something like harvesting are based on an assumption that populations change because individuals give birth and die. However, in addition to reproducing and dying, individuals of most species also grow enormously during life. For example, marine fish may grow from a size at birth of around 1 cm to an ultimate size of several meters. Only recently, we have started to understand what the consequences are of this growth in body size during life for the dynamics of populations of such species. My project aims at synthesizing these recently derived insights with an aim to improve the way we manage populations and communities in the face of human impacts like harvesting.