It's also worth noting that senses may actually take advantage of the inherent noise to improve sensitivity of low level signals using stochastic resonance -- r

It's also worth noting that senses may actually take advantage of the inherent noise to improve sensitivity of low level signals using stochastic resonance -- random resonances of noise and actual signal boosts the measured signal to a level that is detectable, thus permitting detection of signals that are actually below the (noise free) detection sensitivity. Such mechanisms have been observed in animal sensory systems, and is believed to have a role in mammalian visual processing.