The cell as a thermostat: how much does it know?

How does bacterial thermotaxis compare to a simple wall thermostat? Elements with similar function can be found in the two, including a temperature-sensing element, an output switch, and an external control. But they differ in their origins. A thermostat is designed and made by humans and embodies their understanding of seasonal fluctuations in temperature and how these affect room comfort. By contrast, the bacterial system is self-contained and assembles according to information in its genome acquired by evolution. This information is far richer than anything carried by a thermostat and closer to the 'knowledge' that higher animals have about the world.