"Geoffrey Alan Parker" Fellow of the Royal Society/FRS is a Derby professor of biology at the University of Liverpool.

He has a particular interest in behavioural ecology and evolutionary biology, and is most noted for introducing the concept of sperm competition in 1970.

Much of his work from the 1970s onwards has related to the application of game theory (theory of games) to various biological problems, using the evolutionarily stable strategy (ESS) approach pioneered by John Maynard Smith and George Price.

With Dr Robin Baker/R. R. Baker and V. G. F. Smith in 1972, he proposed a leading theory for the evolution of anisogamy and two sexes, and in 1979 made the first theoretical analysis of sexual conflict in evolution. He has also investigated the evolution of competitive mate searching, animal distributions, animal fighting, coercion, intrafamilial conflict, complex life cycles, and several other topics.

More Geoff Parker on Wikipedia.