Taxis

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Taxis is when an organism moves because of a stimulus, like light or food. It’s an inborn behavior. Unlike tropism, taxis involves active, guided movement toward or away from the stimulus source. It can be positive (toward the stimulus) or negative (away from it). An example is Euglena moving toward light, called positive phototaxis.

Taxis can be classified by how the organism senses the stimulus. Klinotaxis means the organism continuously samples the environment to find the direction. Tropotaxis uses two sense organs to compare directions, and telotaxis uses a single organ to determine orientation. There are different taxis based on the type of stimulus as well.