Synchronous oscillatory activity is a universal phenomenon that occurs in biological systems.
“At the heart of the universe is a steady, insistent beat: the sound of cycles in sync. It pervades nature at every scale from the nucleus to the cosmos. Every night along the tidal rivers of Malaysia, thousands of fireflies congregate in the mangroves and flash in unison, without any leader or cue from the environment. Trillions of electrons march in lockstep in a superconductor, enabling electricity to flow through it with zero resistance. In the solar system, gravitational synchrony can eject huge boulders out of the asteroid belt and toward Earth; the cataclysmic impact of one such meteor is thought to have killed the dinosaurs. Even our bodies are symphonies of rhythm, kept alive by the relentless, coordinated firing of thousands of pacemaker cells in our hearts. In every case, these feats of synchrony occur spontaneously, almost as if nature has an eerie yearning for order.”
— A quote from Sync – The Emerging Science of Spontaneous Order by Steven Strogatz
Patterns in nature are connected systems that use complex networks as an internal means of carrying out their function. These networks have a structure that is usually composed of a small-world architecture. These networks also contain dynamic processes that are routed within the network’s architecture. The fireflies noted above can be thought of as network nodes that contain lighting mechanisms. The links between the nodes are the communication or signaling processes that go on continuously between individual fireflies. In this case, the links represent dynamic patterns in time. The Black Bear catching as Salmon is an example of synchrony in time. The bear has arrived at this river during that time of the year when Salmon are running.
This post addresses the subject of synchrony and how synchronous patterns at all levels provide clues as to how nature’s patterns are formed. How they are dynamically driven by processes occurring over time. A synchronous pattern is the relation that exists when things occur at the same time, the simultaneity of events or motions.
Synchrony at a local level can be the energy or force that ultimately results in self-organization at a system level. Two animate or inanimate individuals who operate as coupled oscillators in a synchronous mode at a local level can result in the emergent behavior that is characteristic of complex systems.
According to Wikipedia, “Oscillation is the repetitive variation, typically over time, of some measure about a central value (often a point of equilibrium) or between two or more different states.” Examples of oscillation include swinging pendulums, heartbeats, and tidal rhythms.
There is growing evidence that at the heart of every synchronous pattern in nature is a “coupled oscillator”. An oscillator is a device that causes oscillations to take place. To provide some form of energy that moves in a regular pattern or cycle. There are oscillators that are electrically driven, chemically driven, or behaviorally driven. It appears that any rhythmic pattern is based on an oscillator of some sort.
A coupled oscillator is a series of single oscillators that, with time, cause each other to act or synchronize to a rhythm. A coupled oscillator is a series of synchronized single oscillators. The fireflies noted earlier are an example of coupled oscillators in nature.
Many of nature’s coupled oscillators produce and drive unseen forces that are temporal in nature. These invisible forces are patterns themselves. They are many times the energy or connecting links between visible or more obvious patterns in nature. Sometimes these connecting patterns are the precise rhythms of natural clocks. Others are forces between objects that vary in intensity and period. Nature’s coupled oscillators include circadian clocks, inanimate clocks, human menstrual synchronization, the earth’s moon, and social behavior.
The Circadian Clock
The Greek work “circadian” means “about daily”. Intuitively, we are all familiar with our own biological clock and, at least in general terms, the rhythm of nature. Our own internal circadian pacemaker is a group of cells that act as a chronometer to keep us in synchrony with our world. That pacemaker is a chemically driven coupled oscillator.
One of the effects of a circadian clock is our internal cycle of sleeping and being awake. According to Strogatz, our body’s synchrony operates at three different levels. First, cells within an organ are mutually synchronized much like a coupled oscillator. Second, synchrony occurs between organs keeping the same periodicity even though function may vary. The third level of synchronization is between our body and the world around us.
Our body’s basic clock is a cycle of daily body temperatures. The mechanism within our body that varies body temperature is a coupled oscillator. It is our body temperature mechanism that has a direct effect on the amount and quality of sleep.
A common experiment in physics class involves two pendulums in close proximity. Each pendulum is started with its own periodicity. With time, the pendulums move in synchrony (sometimes called sympathy). The sympathy of pendulums was originally noted by Christian Huygens in 1665 when he found that the pendulums on his two clocks ultimately oscillate together.
Strogatz notes that “the sympathy of clocks taught us that the capacity for sync does not depend on intelligence, or life, or natural selection. It springs from the deepest source of all: the laws of physics”. From this recognition of inanimate sync, the laser was invented as was power grids and computer clocks.
Human Menstrual Synchronization
Extensively studied, human female menstrual cycles can become synchronized amongst women in close physical contact. Apparently this results from chemical communication between women. Strogatz describes an experiment by McClintock and Stern where they ” took swabs from the armpits of women at different points in their menstrual cycles and dabbed them on the upper lips of other women, the donor secretions shifted the phase of the recipient’s cycle in a systematic way”. These experiments imply that coupled biological oscillators are operating.
Our moon turns exactly on its own axis at the same rate as it orbits the earth. The consequence is that we always see only one side of the moon. This is an example of a gravitational/centrifugal coupling between two bodies.
Patterns and synchrony are not restricted to only simply explained phenomena. Strogatz asks: “Could the sudden emergence of a fad be analogous to the way that fireflies suddenly start blinking in unison?” Synchronization of social phenomena is not necessarily rhythmic.
The following 23 minute movie offers a wonderful talk by Steven Strogatz at on the ideas associated with synchrony.
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My name is Bill Graham. As a Marine Biologist who has worked in the US and Mexico for 30 years, I am a student of Nature, a teacher, a researcher, and a nature photographer. Through my work, I have acquired an ever growing passion for how everything in Nature is connected. Today, I travel extensively contemplating about, writing about, and photographing Nature’s connections. I also work with conservation projects in the USA and Mexico and mentor talented youth.