Experimental approaches in biology are often constrained logistically to study low levels of biological organization across small spatial and temporal scales. These constraints largely restrict experimental biologists working on species geographic ranges to study physiological response to climate-related factors, and to assume that geographic distributions reflect physiological tolerance. However, in the reality population-level processes, like ecological interactions and dispersal limitation, may severely narrow realized species distributions compared to physiological-tolerance envelopes. We will present why and how experimental mesocosms and mark-recapture techniques, by allowing population-level inference, may contribute to scale up the predictive power of experiments on the biology of species geographic ranges. We will provide an illustration with an experiment on the effects of temperature and population density on survival and dispersal in the Louisiana crayfish (Procambarus clarkii), a species of invasive concern in many freshwater ecosystems worldwide. We will also briefly discuss how mesocosms may integrate processes acting at higher levels of biological organization, such as the community level.