[js1138]

If by "learning" you mean that an individual organism modifies its behavior as a result of stimuli, then perhaps bacteria do not learn. But the tribe consisting of any strain of bacteria learns through evolution, in a way that is functionally equivalent to the trial and error learning observed in organisms having nervous systems.

[general_re]

But the tribe consisting of any strain of bacteria learns through evolution, in a way that is functionally equivalent to the trial and error learning observed in organisms having nervous systems.

The entire species as a single organism, in effect?

[Right Wing Professor]

But the tribe consisting of any strain of bacteria learns through evolution, in a way that is functionally equivalent to the trial and error learning observed in organisms having nervous systems.

I think that's a unwarranted broadening of the word 'learning', which ususally means the long-lasting change of behavior of an individual in reponse to stimuli. In evolution; some die and some don't, and the population changes, but no individual changes.