Jesus Alberto León was born in La Victoria in the Aragua State of Venezuela on October 19 of the year 1940. Obviously, he is now in his 80s. Jesús Alberto, as many calls him, is now a retired but still active Associated Professor of the Universidad Central de Venezuela (UCV) in Caracas. He taught me the first subject of my doctorate in 2017, Population Ecology. Sorry to confess that his classes are quite complicated, other professors teach with simpler terms and stiles. However, Professor León is dispersed in a funny way. Although, the more important is how he explains the relation between mathematics and biology, especially with ecology and organic evolution. So, if you pay attention to his classes you get in love more with the “spooky” mathematics.

He started his career graduating in Biology at the UCV in 1963. The next year he received another title in Mathematics at the same university. Beginning to work and teach at the UCV almost for a decade before he went to study his doctorate at the University of Sussex in the United Kingdom, obtaining his PhD in 1975. Because I am also familiar with England, I asked him about life there, especially rock concerts. He told me that he was able to saw groups like Pink Floyd, Rolling Stones, Genesis and even Queen (some of my favorites). On the contrary, he prefers the oldest Beatles, and when the name of a pupil is Michelle - especially a girl - he sang that Beatle’s song at classes in perfect English… and also the French part of course.

Back in his first contributions as a researcher, he published several outstanding papers and documents in the 70s and 80s. The first two at the Journal of Theoretical Biology as part of his doctorate in the UK: Competition between Two Species for Two Complementary or Substitutable Resources in 1975 with his colleague Dr. Daniel Tumpsom, and Life Histories as Adaptative Strategies in 1976 published alone.

One of the main aims of the first article is that they describe mechanisms of competition of species in relation with the resources, explained them in geometrical views paired with his math equations and logic explanations of the outcomes: linear, for perfect substitutable resources; rectangular, for perfectly complementary resources; convex, for imperfectly substitutable resources, and perpendicular, for essential resources. The form of these lines has repercussions on the way the population growths using the available resources.

The second paper mentioned above, and his first English article published in The American Naturalist in 1974 had evolutionary implications. Early ecological ideas of community stability declared that: “As more species have a community, more relations occur, but stability and persistence decrease. Then as time passed, community complexity tends to decrease as well. Nevertheless, we observe the contrary”. León showed that genetic variability and natural selection gave origin to more stable communities that preserve complexity. This opened a new field of research called Evolutionary Ecology.

In total he wrote almost 30 scientific documents between papers for top magazines like Biometrics and Ecology, lectures, book chapters, and divulgation notes.

Another interesting feature of Professor León was that he performed exams during midday weekends and several times inviting his students to lunch. Nowadays, this courtesy is almost impossible due to the hyperinflation in Venezuela, but for more than 35 years, university professors earned very comfortable salaries at the local institutions. Jesús Alberto was politically active in the 60s. But after seeing what happened in the world and particularly in his country with the new century, he changed his ideas from the extreme left to a democratic and economically balanced center. He was a visiting professor at Harvard, Stanford, Trieste, Sao Paulo and Tokyo Universities.

He also plays cuatro, our local four-string guitar similar to the ukulele, and writes poetry, with almost ten books published and two prices awarded. In early 2001 he earned the national famous Polar Science Award given by Polar Enterprise Foundation.

If you meet him at the spaces of the UCV, he talks with you about different subjects with a big smile, invites you a coffee plus something more to share. He is humble in his dressing and his old car, named after the big predator, the white shark. He feels great proud, and almost with a healthy vanity, of his intellectual achievements especially in the biomathematics field. For me, and many of my colleagues, Jesús Alberto León can be considered among the greatest theoretical ecologists of the planet like Hutchinson, MacArthur, Paine, Gause, Tilman, Lotka and Volterra.


León, J.A. 1974. Selection in contexts of interspecific competition. The Amer. Nat. 108:739-757.
León, J.A. Y D.B. Tumpson. 1975. Competition between Two Species for Two Complementary or Substitutable Resources. J. Theor. Biol. 49:241-244.
León, J.A. 1976. Life Histories as Adaptative Strategies. J. Theor. Biol. 60:301-335.
Rodríguez, D. 2002. La obra intelectual y académica de Jesús Alberto León. Acta Biol. Venezuelica. 22(1-2):1-6.