Nature is a full of diverse life history strategies (demographic diversity); however, our understanding of its effects on community structure and dynamics is still limited. I compared a food web model with stage-structured populations with an equivalent model with unstructured populations. Both models included the maximum of 15 populations, incorporated energetic processes, and allowed existing populations to go extinct and new populations to invade over time. Although results from these two models shared some similarities, there were also clear differences between them. For example, reducing niche width led to an increased number of populations under the unstructured model, but led to a reduced number of populations under the structured model. Although the number of populations in both models was very similar after attaining stability, the average trophic level of consumers in the structured model was almost always higher than in the unstructured model. When the structured model reached stability, three distinct life history strategies emerged, corresponding to life history strategies observed in aquatic systems. These results compel the need for a re-evaluation of current understanding in community dynamics, developed mostly without considering population stage structures.