on Malthusian relativity

Malthusian relativity is a natural selection theory that predicts the evolution of the major lifeforms on Earth from the origin of replicating molecules. It is based on a selection mechanism that was noted, but never explicitly formulated, by Darwin.

When Darwin read Malthus (1798) in 1838 he realised not only that 'a struggle for existence inevitably follows from the high rate at which all organic beings tend to increase' but also that 'the struggle almost invariably will be most severe between the individuals of the same species' (Darwin, 1859). Yet, instead of showing---by cause and effect---how the density-dependent interactive competition selects the biological diversity on Earth, Darwin argued that species evolve from common ancestors by natural selection.

The link---from population growth to selection by individual interactions---was not taken seriously as a necessary and sufficient mechanism for the natural selection of know lifeforms before I proposed Malthusian relativity in 1997. The name of the theory reflects its core mechanism, where interactive competition selects organised lifeforms by a density-frequency-dependent relativity in the Malthusian parameter (r) of the individuals in the population.

While mechanistically somewhat complex, the selection of Malthusian relativity is conceptually rather simple: Replicating molecules with no metabolism have selection for an internal metabolism that generates net energy for self-replication. The selected increase in self-replication generates a gradual unfolding of a feed-back selection between the resulting population growth and its associated interactive competition. The gradual unfolding of the feed-back selects for evolutionary transitions from replicating molecules over prokaryote and eukaryote like unicells to larger multicellular animals with sexual and eusocial reproduction.

Being based on the conservation of energy, population growth, and interaction this selection and evolution is predicted as a deterministic and inevitable unfolding from the origin of replicating molecules (given physical conditions suitable for life).

The original 1997 version of Malthusian relativity covered the natural selection transition from small asexual self-replicators to large sexually reproducing animals with body mass allometries, and eusocial reproduction in some instances. It took twenty additional years to account for the natural selection of metabolism, explaining evolutionary transitions from replicating molecules over prokaryote and eukaryote like unicells to multicellular animals. By 2024, I used the framework to estimate the life history diversity and population dynamics across the birds and mammals of the world.

The mrLife.org web-page describes the essential concepts, predictions, and evidence. It includes free downloads of the original scientific work and allows for population dynamic simulations of birds and mammals.

Please enjoy the wonders of unfolding life

Lars Witting / February 11, 2024, Nuuk