The living world is made up of complex biological systems. At the level of the individual, the most complex of these systems is the human brain. But the process of evolution has produced even more complex systems, such as tropical reefs and rainforests, that are made up of millions of interacting species. UCSD Professor of Ecology Christopher Wills explores how this complexity evolved and what genetic and ecological processes complex systems have in common.  Series: "Evolution Matters" [Science] [Show ID: 13546]