Research Suggests a Known Physics Phenomenon Creates the Color Patterns on Animals' Skin

Scientists couldn't explain the sharp borders in color patterns seen throughout nature, but new research may have answers

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We stare in awe and wonder at the designs and vibrance of the color patterns plants and animals possess and naturally want to understand them. Researchers have identified several biological purposes these patterns serve, like camouflage and attracting mates, which are relatively common knowledge, but it only explains why these color patterns evolved.

How the patterns form is a whole other mystery that confounds researchers. After all, the patterns and colors on an animal’s skin or a flower’s petal must be distinctive for any evolutionary purpose to be effective. Yet, this seemingly small detail has been anything but simple to explain — but now researchers at the University of Colorado Boulder may bring us one step closer to solving the mystery.

A Bit of Physics

Revisiting a bit of physics will help us understand why the colored patterns in nature have baffled scientists and why the new research matters. Basically, though, it all comes down to a process you’re already familiar with — diffusion.

You know that if you add one drop of yellow and one drop of blue food coloring to a glass of water, the dyes will spread and ultimately mix to become green. This process is called diffusion and explains how molecules in high concentrations move into areas of lower concentration.

In the food dye example, the yellow and blue dyes disperse from the concentrated drops falling from the bottles into the less concentrated water in the cup. Eventually, both colors will once again become evenly concentrated within the water and become green.

Considering this well-known fact, the main question facing scientists is: How can distinct color patterns in nature form at all? Shouldn’t diffusion prevent this?

In 1952, The Royal Society published The Chemical Basis of Morphogenesis by Mathematician Alan Turing, which brought the scientific world a step toward answering these questions.

In his paper, Turing showed how, under certain conditions, the chemical reactions involved in producing color can counteract diffusion. These reactions allow for colors to self-organize and create areas with different colors. In other words, he said chemical reactions between different colors form the patterns. The result is what scientists now call Turing patterns.

Turing’s theory of chemical pattern formation, which has been thoroughly and repeatedly demonstrated, also helps explain other puzzles in biological development.

Such as the patterns on a plant’s leaves and flowers or the symmetry of leaves growing along a stem. Turing theory even extends beyond biology or chemistry, though; it also helps explain how ants dispose of dead bodies, why crime happens the most in ‘hotspots,’ and how sand ripples form.

While Turing’s theory has broad implications and plenty of promise, it doesn’t fully explain how color patterns in nature are so distinct. Mathematically, diffusion causes the color boundaries to blur rather than have distinct edges.

Try as they might, scientists have remained stumped for decades about what allows colors to form such distinct, non-blurry borders. But new research may finally have an answer.