Biological complexity: protozoal movement, no brain (Introduction)

by David Turell , Saturday, October 15, 2022, 00:19 (771 days ago) @ David Turell

Pattern movement observed:

https://www.sciencealert.com/clockwork-like-computer-discovered-inside-brainless-micros...

"microscopic pond dwellers called Euplotes eurystomus have mastered a way to walk brainlessly – scurrying about like insects, with their 14 little appendages.

"They appear to move a bit like the Dutch-designed kinetic sculptures called Strandbeasts, with clockwork-like connections cycling them through a pattern of set states that can be adjusted in response to their environment.

"'There seemed to be this sequential logic happening with the movements," says biophysicist Ben Larson from the University of California, San Francisco (UCSF). "They weren't random, and we began to suspect there was some sort of information processing happening."

"These protozoans – single-celled organisms with animal-like characteristics – have 14 stingy bundles of cilia that work together as legs called cirri. They can use these cirri to swim and walk while actively hunting for prey.

***

"The cirri are made of tubulin fibers, like the rest of the cell's scaffolding structures (its cytoskeleton). These fibers also act as a support structure between the different cirri so they also function as a kind of mechanical communication.

"'Euplotes uses these connections to facilitate an elaborate walking motion, " explains UCSF biophysicist Wallace Marshall.

"Computer modeling revealed that tension and strain on the fibers dictated which set pattern of cirri positions was possible at each moment. Some cirri store stress at different stages of a gait; when that stress is released it propels the cell to move forward into the next state, causing a cyclic transition between these states."

Comment: programmed biochemical reactions can easily create this animal's movement. Other sngle-celled animals move their bodies, as amoba sith no legs.