Medina (Dr. Ack., U. of Hohenheim, 1964) has worked as senior researcher and head of the Lab. for Plant Physiological Ecology, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas. He also served as: Dir., Intl. Ctr. for Tropical Ecol., IVIC-UNESCO; member, Intl. Scientific Adv. Board, Max-Planck-Inst. f. Limnologie; member, Adv. Comm., Scientific Comm. on Problems of the Environ. (ICSU); FAO adviser, Environ. and Develop.; and member, Coord. Comm. for Research, Int. Union of Biol. Sciences. His honours include: Carnegie fellow; Andres Bello Order; Lorenzo Mendoza Fleury Prize; Guggenheim fellow; hon. member, Ecol. Soc. of America; for. assoc., Natl. Acad. of Sciences, USA; for. member, Am. Acad. of Sciences; Bacardi chair, Univ. of Florida; for. assoc., Natl. Acad. of Sciences, USA; for. fellow, Am. Acad. of Arts and Sciences; and for. member, Am. Acad. of Sciences. Adjunct Scientist at IITF-USDA Forest Service