A growing wealth of evidence from fossil records, modern genetics, biochemistry, and field biology is clarifying the picture of how life evolved on Earth over the last three billion years and how it continues to change.  Missing links are being filled in and evolution is being witnessed live in action.

Now researchers are beginning to discover how to leverage the power of modern computing simulations to explore pressing questions in the field of evolutionary biology.  Scientists at the University of Minnesota's Institute of Technology have just completed a study which uses hydrodynamic simulations of fish to help understand how their environment helped shape their evolution.

Civil Engineering Professor Fotis Sotiropoulos and postdoctoral researcher Iman Borazjani began the project over five years ago, looking to simulate the model fish in a massive parallel computer cluster.  The work was quite challenging.  Describes Professor Sotiropoulos, "It was a challenge because we had never simulated anything living before."

However, the pair were able to use their strong knowledge of hydrodynamics to develop a plan of attack.  They created four swimming fish -- two computational mackerels (one that beat its tail like a mackerel and a second that wriggled like an eel) and two eels (one that wriggled and another that beat its tail like a mackerel).  They then sent the digital fish out through a variety of water conditions, varying the fluid velocity-dependent viscosity.  They then examined the fish traveling at various tail-beat speeds and looked at the efficiency of the motion.

What they found was that fish with inappropriate tail motions or body shapes moved less efficiently, which in the real world would equate to tiring quicker.  Tiring quicker could lead to losing the chance to catch prey or, worse yet, being eaten.  In slow currents (such as a reef) the eel shape was preferred, while in fast currents (open sea) mackerel shape was preferred.

Thus the research shows important evidence of how selective pressures may have given rise to fish in their modern shape.  It also demonstrates how computer simulations can be used to better understand natural selection and the course of evolution.

Professor Sotiropoulos is quite pleased with the results.  He states, "From these experiments, we can deduce that real mackerel and eel's swimming styles are perfectly adapted to the hydrodynamic environments that they inhabit."

The study was published in the Journal of Experimental Biology.

The research not only offers insight into evolution, but could also be used to create more efficient swimming robots, according to the researchers.