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Figure 11: Graphic of Lotka-Volterra workflow
The Lotka-Volterra model was developed independently by Lotka (1925)2 and Volterra
(1926)3 and is made up of two differential equations. One describes how the prey
population changes (dn1/dt = r*n1 - a*n1*n2), and the second equation describes how the
predator population changes (dn2/dt = -d*n2 + b*n1*n2).
The Lotka-Volterra model is based on certain assumptions:
• the prey has unlimited resources;
• the prey's only threat is the predator;
• the predator is a specialist (i.e., the predator's only food supply is the prey); and
• the predator's growth depends on the prey it catches
The Lotka-Volterra model as represented in Kepler as a scientific workflow contains:
• six actors - two plotters, two equations, and two integral functions;
• one director; and
2
Lotka, Alfred J (1925). Elements of physical biology. Baltimore: Williams & Williams Co.
3
Volterra, Vito (1926) Fluctuations in the abundance of a species considered mathematically. Nature 118.
558-560.
21