Data from: The evolutionary origins of modularity

A central biological question is how natural organisms are so evolvable
(capable of quickly adapting to new environments). A key driver of
evolvability is the widespread modularity of biological networks--their
organization as functional, sparsely connected subunits--but there is no
consensus regarding why modularity itself evolved. While most hypotheses
assume indirect selection for evolvability, here we demonstrate that the
ubiquitous, direct selection pressure to reduce the cost of connections
between network nodes causes the emergence of modular networks.
Computational evolution experiments with selection pressures to maximize
network performance and minimize connection costs yield networks that are
significantly more modular and more evolvable than control experiments
that only select for performance. These results will catalyze research in
numerous disciplines, including neuroscience, genetics and harnessing
evolution for engineering purposes.