Evolution of Microorganism Locomotion Induced by Starvation

G.J. SIBONA

Amsterdam, Holanda

Otro; Biolateral Triangle Meeting 2005.; 2005

Biolateral Triangle Meeting 2005.

The search strategies of many organisms play a fundamental role in their competition to survive in a given environment. In this context, the propulsion systems of microorganisms have evolved during life-history, to optimize the suitable use of energy they take from nutrients. Starting from a model for the motion of Brownian objects with internal energy depot, we show that organisms have an optimal regimen in their search of new sources of food. Bacteria with a too low or too high energy expenditure in propulsion, moving in a nutrient depleted environment, do not reach remote distances. In this sense, the mean square displacement has a maximum for a finite value of the propulsion rate. Then, species using the most efficient locomotion system have a considerable advantage to survive in hostile environments, a common situation in the ocean. Moreover, we found the existance of a lower size limit for usefull locomotion. Then, we can assure that for organisms smaller than a certainmechanism at all. A result that is in agreement with what it is observed in nature. threshold is convenient for its survival not to use any propulsion