Competition for resources has long been believed to be fundamental
to the evolution
of diversity. However, the
difficulty of working with natural ecosystems has meant that this
theory has rarely been tested. Here, we use the Avida
experimental platform to demonstrate the evolution of
ecosystems
composed of digital
organisms
. We show that stable ecosystems
are formed during evolution in an environment where organisms must
compete for limiting resources. Stable coexistence was not observed
in environments where resource levels were not limiting, suggesting
that competition for resources was responsible for coexistence. To
test this, we restarted populations evolved in the resource-limited
environment but increased resource levels to be non-limiting. In
this environment, ecosystems previously supporting multiple
genotypes could maintain only a single genotype. These results
demonstrate the utility of the Avida platform for addressing
ecological questions and demonstrate its potential in addressing
questions involving ecosystem-level processes.