Simulation of a chemostat bioreactor.

X = microbiological mass
S = substrate concentration
D = dilution rate
Y = yield of microbiological massfrom a unit of substrate
mu = maximum growth rate
Ks = Michaelis-Menten-constant

A damped, driven pendulum. The combination of damping and driving provokes a minimal case of chaos. The system is not in itself biological, however its chaotic behaviour arises from competing oscillatory influences - a situation which plays a role in many biological systems.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Este modelo presenta una modificación del proyecto 0409: Daisyworld, la cual consiste en agregar una especie gris de margaritas que compita con las otras dos especies por el espacio en el suelo.

This simple, generic biological integral-control component is used by E. coli to decide on an adaptive tumbling frequency.

1. If Ligand concentration stays constant, the bacterium tumbles at a low, exploratory rate of ~2 Hz.

2. If Ligand concentration rises (attractant), tumbling frequency falls to continue moving toward the source.

3. If Ligand concentration falls (repellant), tumbling frequency rises to avoid the source.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

A simple implementation of Koeslag & Saunders' IRC model of blood-glucose regulation.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

A damped, driven pendulum. The combination of damping and driving provokes a minimal case of chaos. The system is not in itself biological, however its chaotic behaviour arises from competing oscillatory influences - a situation which plays a role in many biological systems.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

This is an example of how to model populations involving recombination and mutation. The Hardy-Weinberg Law gives us the effects of recombination, and mutation is represented by a flux between alleles.

Possible extensions: Build in differential fitness of the three genotypes, have them differentially interact with an external environment, or have them interact with each other. (There is already an interaction term in the three 'die' flows.)

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.

Darwinian Daisyworld model from and Watson & Lovelock (1983), Robertson & Robinson (1998) and Lenton & Lovelock (2001).

Units of time are 40 Myr, giving R&R's span of 10 Gyr.

This model offers many opportunities for modification. Maybe the Black and White populations can mutate into each other? The role of q as a measure of segregation of the B and W populations is interesting, and while this model uses purely stigmergic communication between species, direct interaction would also be possible.