Unified physics theory explains animal locomotion


A single unifying physics theory describes how animals of every ilk, from flying insects to fish, get around. The team reports that all animals bear the same stamp of physics in their design.


A single unifying physics theory can essentially describe how animals of every ilk, from flying insects to fish, get around, researchers at Duke University's Pratt School of Engineering and Pennsylvania State University have found. The team reports that all animals bear the same stamp of physics in their design.

The researchers show that so-called "constructal theory" can explain basic characteristics of locomotion for every creature -- how fast they get from one place to another and how rapidly and forcefully they step, flap or paddle in relation to their mass. Constructal theory is a powerful analytical approach to describing movement, or flows, in nature.
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They said their findings have important implications for understanding factors that guide evolution by suggesting that many important functional characteristics of animal shape and locomotion are predictable from physics.

"From simple physics, based only on gravity, density and mass, you can explain within an order of magnitude many features of flying, swimming and running," added James Marden, professor of biology at Penn State. "It doesn't matter whether the animal has eight legs, four legs, two, even if it swims with no legs."
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The findings may have implications for understanding animal evolution, Marden said. One view of evolution holds that it is not a purely deterministic process; that history is full of chance and historical contingency. It is the idea purported by Steven Jay Gould and others that if you were to "rewind the tape" and run it again, evolution would proceed down a different path, Marden said.

"Our finding that animal locomotion adheres to constructal theory tells us that -- even though you couldn't predict exactly what animals would look like if you started evolution over on earth, or it happened on another planet -- with a given gravity and density of their tissues, the same basic patterns of their design would evolve again," Marden said.

Fascinating work. Don’t miss the logic and analysis required to figure out fish!

Posted: Fri - December 30, 2005 at 08:05 AM