HSCI-260: Pattern Formation in Nature

Why do similar patterns and forms appear in nature in instances that seem to bear no relationship to one another? The windblown ripples of desert sand have a sinuous pattern that resembles the stripes of a zebra or a marine fish. The three dimensional trellis-like skeletons of microscopic sea creatures contain the same angles and intersections as those in a wall of foam or bubbles. The stepped leaders of a lightning bolt mirror the branches of a tree, or the drainage basin of rivers. These are not mere coincidences. Are the sizes (and sometimes even the shapes) of 'creatures great and small' actually determined by the laws of physics and chemistry? Nature commonly weaves its tapestry by employing 'self-organization,' rather than relying upon some master plan or blueprint. Physical forces, such as gravity and surface tension, shape the form of all living things in ways both subtle and profound. Simple, local interactions between its component parts - be they grains of sand, living cells, or even diffusing molecules - are all that are necessary to produce a myriad of forms. The products of self-organization are typically universal patterns: spirals, spots, and stripes, branches or honeycombs.