  Biological systems reach hierarchical complexity that has no counterpart
outside the realm of biology. Undoubtedly, biological entities obey the
fundamental physical laws. Can today's physics provide an explanatory framework
for understanding the evolution of biological complexity? We argue here that
the physical foundation for understanding the origin and evolution of
complexity can be envisaged at the interface between the theory of frustrated
states resulting in pattern formation in glass-like media and the theory of
self-organized criticality (SOC). On the one hand, SOC has been shown to emerge
in spin glass systems of high dimensionality. On the other hand, SOC is often
viewed as the most appropriate physical description of evolutionary transitions
in biology. We unify these two faces of SOC by showing that emergence of
complex features in biological evolution typically if not always is triggered
by frustration that is caused by competing interactions at different
organizational levels. Competing interactions and frustrated states permeate
biology at all organizational levels and are tightly linked to the ubiquitous
competition for limiting resources. This perspective extends from the
comparatively simple phenomena occurring in glasses to large-scale events of
biological evolution, such as major evolutionary transitions. We therefore
submit that frustration caused by competing interactions in multidimensional
systems is the general driving force behind the emergence of complexity, within
and beyond the domain of biology.
