1868-1944

German zoologist whose textbook Ecological Animal Geography (1924) set the standard for biogeography study, covering the distribution of animal life in terrestrial, freshwater, and marine ecosystems. Hesse recognized that the distribution patterns of animal life are correlated to the complex relationships that exist between all species of an ecosystem and all the nonliving factors of each ecosystem. Hesse emphasized the need for careful observation and experimentation to foster the young science of ecological animal geography.