Motility: Life in Syrup

All protozoa show some sort of motility: practically all forms move freely in the environment during at least some part of their life cycle. Even species that are normally sedentary show motility in the form of contraction or the ability to generate water currents from which food particles may be strained. All protozoa, of course, show a sort of motility during phagocytosis, during the process of “cyclosis” (the intracellular movement of food vacuoles and other organelles) and during cell division. These last-mentioned aspects of protozoan motility will receive little attention here. Instead, we will concentrate on swimming, the generation of feeding currents, creeping motility on surfaces, and, in a following chapter, motile behaviour that allows the organisms to orientate themselves with respect to environmental gradients of different sorts.