Trackways show, animals 50 million years ago used Levy random walk to search for food
|July 17, 2014||Posted by News under Animal minds, News, stasis|
Still do today. Must’ve worked, like mathematicians say.
Animals have used the same technique to search for food that’s in short supply for at least 50 million years, a University of Southampton-led study suggests.
Researchers analysed fossilised sea urchin trails from northern Spain and found the tracks reflect a search pattern still used by a huge range of creatures today.
But this is the first example of extinct animals using such a strategy.
The findings could explain why so many modern animals use the technique, and suggest the pattern may have an even more ancient origin.
Actually, the findings don’t necessarily explain why modern animals use the technique. They don’t do the math either. It could be natural selection acting on random mutation (Darwinian evolution), it could be unrelated animals arriving at the same successful technique (convergent evolution), or for all we know, it could be horizontal gene transfer of genes that govern the initiation of such a search, or epigenetics (strategy arrived at in lifetime of individual gets encoded in the genes). All these processes sometimes occur.
Creatures including sharks, honeybees, albatrosses and penguins all search for food according to a mathematical pattern of movement called a Lévy walk — a random search strategy made up of many small steps combined with a few longer steps. Although a Lévy walk is random, it’s the most efficient way to find food when it’s scarce.
Even though a wide range of modern creatures search for food according to this pattern, scientists had no idea how the pattern came about, until now.
Professor Sims and colleagues from the University of Southampton, NERC’s National Oceanography Centre, Rothamsted Research, VU University Amsterdam and the Natural History Museum analysed the fossilised Eocene-era tracks that were made by sea urchins that lived on the deep sea floor around 50 million years ago. The long trails are preserved in rocky cliffs in a region called Zumaia in northern Spain.
“The patterns are striking, because they indicate optimal Lévy walk searches likely have a very ancient origin and may arise from simple behaviours observed in much older fossil trails from the Silurian period, around 440 million years ago,” he adds.
Now that will be interesting, if demonstrated.
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