  Models of asexually reproducing populations in varying environments have
provided insights into the diversity of adaptive strategies, revealed deep
analogies with information theory and stochastic thermodynamics, and inspired
quantitative methods to analyze single-cell experiments. Here we show how these
models can be generalized to sexually reproducing populations. The resulting
framework is applied to two fundamental questions. First, what are the
conditions under which sexual reproduction is advantageous over asexual
reproduction? Second, what are the conditions under which sexual dimorphism,
the presence of two phenotypically distinct sexes, is advantageous? We study
these questions from the two standpoints of optimal information processing and
evolvability. Our analysis provides a new perspective on long-standing problems
as well as fresh insights into unexamined questions. More generally, it opens
the door to novel interdisciplinary approaches to a central problem of
evolutionary biology, the role of sex in adaptation.
