Published November 21, 2025 | Version Published
Journal Article Open

Analogies between the virial theorem and the Price equation

  • 1. ROR icon California Institute of Technology
  • 2. Flintridge Preparatory School, La Cañada, California

Abstract

We observe that the time-averaged continuous Price equation is identical to the positive momentum virial theorem, and we discuss the applications and implications of this connection. We also introduce ecological models using a maternal effect, which can describe arbitrary population size cycles and trait evolution across spatially separated populations. The virial theorem sheds light on the time-averaged behavior of these models.

Copyright and License

 ©2025 American Physical Society.

Acknowledgement

S.L. thanks Manoj Kaplinghat and Gopolang Mohlabeng for their introduction to the virial theorem. L.P. thanks Junhyong Kim for discussions on the connection of this work to ecological orbits. C.F. was partially supported by funding from Caltech's CI2 grant program.

Funding

C.F. was partially supported by funding from Caltech's CI2 grant program.

Contributions

S.L. and L.P. developed the connections between the virial theorem and the Price equation. C.F. identified and developed the connection to ecological orbits and simple harmonic motion via the maternal effect. S.L. and L.P. drafted the initial manuscript; C.F., S.L., and L.P. edited the final version and code.

Data Availability

The data and scripts for generating figures are available at [63].

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Additional details

Additional titles

Alternative title
The virial theorem and the Price equation

Related works

Is new version of
Discussion Paper: arXiv:2312.06114 (arXiv)
Is supplemented by
Dataset: https://github.com/pachterlab/FLP_2024 (URL)

Funding

California Institute of Technology
Caltech CI2 Grant Program

Dates

Submitted
2025-01-03
Accepted
2025-10-16

Caltech Custom Metadata

Caltech groups
Division of Biology and Biological Engineering (BBE), Division of Physics, Mathematics and Astronomy (PMA)
Publication Status
Published