The paper analyzes research on the global latitudinal gradient of biodiversity, one of the fundamental patterns in ecology and biogeography. The evolution of ideas is traced from the early observations of nineteenth-century naturalists (Humboldt, Wallace) to contemporary quantitative and model approaches. It categorizes and critically analyzes the key hypotheses explaining the increase in species richness in the tropics, including time, climate stability, productivity, spatial heterogeneity, biotic interactions, and area-related hypotheses. It pays special attention to the dynamic nature of the latitudinal gradient of biodiversity through geological time, based on the analysis of paleontological evidence of “flat”, bimodal, and inverse gradients during periods of global warming and mass extinction events. The concepts of the tropics as a “cradle” (center of speciation) and “museum” (low-extinction zone) are integrated, along with the related ideas of “phytospreading” and the “equatorial pump”. The review suggests that the latitudinal gradient of biodiversity is a dynamic pattern formed by the complex interplay of ecological, evolutionary, and historical factors, whose relative roles vary by taxon, region, and geological period.
S.N. Sheremetyev (Wed,) studied this question.