Robert May, Baron May of Oxford, a physicist whose work pioneering theoretical ecology lead to the development of chaos theory, has passed away on April 28, 2020. One of the greats is gone!!! 

https://en.wikipedia.org/wiki/Robert_May,_Baron_May_of_Oxford

His paper "Simple mathematical models with very complicated dynamics" published in Nature in 1975 has been very influential for the development of chaos theory.