We talked recently about robots used for a lunar simulation. Today’s story also involves robots, but for evolutionary biology – the study of how animals evolved over time.

A team from the University of Utah’s Department of Geology and Geophysics created robotic ammonites. Most closely related to modern squid and octopus, these animals used to fill oceans for hundreds of millions of years before dying out with the land dinosaurs at the end of the Cretaceous period.

Scientists are studying these animals as an example of natural selection. Based on their shell’s awkward shape and size they shouldn’t have been as successful as they were. Many different variants of shell shapes are preserved in the fossil record, in many different environments and times. The researchers picked three different shapes to represent a spectrum of possible shell types. One was cone-shaped, and another was almost spherical. The third was in the middle. The shells were then 3D printed, which required the 3D printed shell to be watertight, both to preserve the intended buoyancy of the test article and protect the electronics.

The researchers did a dozen runs of each shell type in a pool at the university, filming each run and plotting it in 3D coordinates. No single shape was good at everything. As researcher David Peterman noted, trying to find the best shape for all situations is not the right question, saying: The idea that one shape is better than another is meaningless without asking the question—‘better at what?’.

The narrower shell was faster and more stable, but could not change directions easily. The round shell was slower but could change directions more easily. Each animal likely evolved the shell shape needed for its specific environment.

More Information

The University of Utah press release

“Resurrecting extinct cephalopods with biomimetic robots to explore hydrodynamic stability, maneuverability, and physical constraints on life habits,” David J. Peterman and Kathleen A. Ritterbush, 2022 July 4, Scientific Reports