"A system does tend toward disorder, which is the lowest "energy state" of the system, so how could evolution go in the other direction? It's because the Sun is always injecting new energy into the system, and it does it in a way that is harnessed by biochemistry and the ecosystem. The Earth is an open system, not a closed one. New energy in the form of sunlight is the first step of an "energy gradient" that flows through the ecosystem of life at multiple levels. This energy gradient drives the biochemistry of evolution: sunlight -> photosynthesis -> ATP production -> complex molecule construction -> food -> growth and reproduction (+ mutation) -> evolution. If the Sun were to "turn off" tomorrow, then evolution would come to a stop and life on earth would freeze over and decay into a lifeless rock." --Paul King - Adriano