Chapter 29
Biosynchronicity
With Heav’nly touch of instrumental sounds In full harmonic
number joind.
(1667 Milton)
29.1 Firefly Model
We know from the observation of fireflies in India that whole trees containing tens of
thousands of these insects begin to blink in unison shortly after dusk [1]. Casual
observation of the sounds of nighttime insects around the common suburban home
shows us that audio-synchronous behavior occurs. We assume some group reproduction advantage is conferred by such synchrony. The pacemakers in the heart of every
mammal are really the synchronous pulsing of thousands of special cells, yielding
sufficient signal to cause a muscle action. What process allows such synchronization?
How can these organisms and even cells conform to each other’s signal?
Apparently, Charles Peskin of New York University first successfully formulated a model of this process. Nearly any electrical engineer would understand the
process immediately, as he began with an electrical analogy: a resistance and a
capacitor in parallel, subjected to a steady electrical current input. The voltage
builds on the capacitor to a limit when it suddenly discharges and the voltage drops
quickly to zero, only to repeat the process. This system is analogous to a weight
hanging on a damper, subjected to a constant extending force. When the damper
reaches its limiting extension the velocity of the weight becomes zero.
In the model, we represent four fireflies by four cells of a spatial model. The state
variable for each cell is the “voltage” V—or brightness—of the cell. We choose
different starting values for each cell in order to get the cells initially out of phase.
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_29,
© Springer International Publishing Switzerland 2014
241
Biosynchronicity
With Heav’nly touch of instrumental sounds In full harmonic
number joind.
(1667 Milton)
29.1 Firefly Model
We know from the observation of fireflies in India that whole trees containing tens of
thousands of these insects begin to blink in unison shortly after dusk [1]. Casual
observation of the sounds of nighttime insects around the common suburban home
shows us that audio-synchronous behavior occurs. We assume some group reproduction advantage is conferred by such synchrony. The pacemakers in the heart of every
mammal are really the synchronous pulsing of thousands of special cells, yielding
sufficient signal to cause a muscle action. What process allows such synchronization?
How can these organisms and even cells conform to each other’s signal?
Apparently, Charles Peskin of New York University first successfully formulated a model of this process. Nearly any electrical engineer would understand the
process immediately, as he began with an electrical analogy: a resistance and a
capacitor in parallel, subjected to a steady electrical current input. The voltage
builds on the capacitor to a limit when it suddenly discharges and the voltage drops
quickly to zero, only to repeat the process. This system is analogous to a weight
hanging on a damper, subjected to a constant extending force. When the damper
reaches its limiting extension the velocity of the weight becomes zero.
In the model, we represent four fireflies by four cells of a spatial model. The state
variable for each cell is the “voltage” V—or brightness—of the cell. We choose
different starting values for each cell in order to get the cells initially out of phase.
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_29,
© Springer International Publishing Switzerland 2014
241