Cellular Ethological Dynamics in Diorama Environments

How smart can cells behave under complicated environmental conditions in their natural habitat? Further, what physical mechanism brings about such smart behaviors? These two questions are closely related to each other and are to be studied in both cell biology and physics. Here, we focus on behavioral smartness and variability observed mainly in unicellular eukaryotic organisms. We review a few typical cases in which cell behavior seemed smart in a complex experimental condition and=or variable in a similar experimental condition. On each of these behaviors, a possible mechanism was considered by formulating and analyzing the model equations of cell motion. By revisiting the thought that cells might be simple machines that could repeat the same response to the same stimuli and conditions, we threw some light on the plausible mechanisms for behavioral smartness and variability in cellular movements.