Slime Mold

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Plasmodial Slime Mold

This Time Machine illustrates growth and movement in the plasmodial slime mold Physarum polycephalum. Despite its name, Physarum is not a real mold or fungus; it is a protist and more closely related to amoeba than to mold. The structure growing in the dish is a plasmodium, which does not have internal cell walls and contains a continuous and constantly streaming protoplasm. The plasmodium surrounds its food and secretes enzymes to break it down.

Thirty hours of single images taken with a Canon Rebel T2i were used to make this timelapse. The images were taken at the CREATE lab at Carnegie Mellon University in collaboration with Janet Steven from Sweet Briar College. The first few seconds of the timelapse use images that are 5 minutes apart; the remainder of the timelapse uses images taken ten seconds apart.

Physarum is easy to grow in culture, and is commonly used in biology courses. It is also a model organism in biological research. In the wild, it grows on dead plant matter in moist temperate forests. This culture was ordered from a biological supply company, and is growing on an agar medium with oat flakes as its food source.

Watch a time warp of plasmodial growth.

The ability of Physarum to develop efficient connections between food sources makes it a potential tool for planning networks of all kinds. In a Japanese study, Physarum generated a map for the Tokyo rail system comparable in efficiency and fault tolerance to the existing system. [1]

Regular changes in the direction of protoplasmic flow cause the plasmodium to pulse rythmically. Changes in protoplasmic flow aid in movement of substances throughout the plasmodium and play a role in net movement.

Watch a time warp of pulsing of the plasmodium.


  1. Tero, A. et al. 2010. Rules for biologically inspired adaptive network design. Science 327:439-442.