Does Gaia Play Dice? : Simple Models of non-Darwinian Selection

TL;DR

This paper introduces simple dice-based models to analyze non-Darwinian selection mechanisms affecting planetary habitability, revealing that some apparent improvements over time are due to sampling effects, while others show genuine tendencies.

Contribution

It provides analytically tractable models to distinguish between sampling effects and true selection trends in non-Darwinian processes affecting habitability.

Findings

Selection by Survival and Sequential Selection are influenced by sampling effects.

Sequential Selection with Memory shows a genuine tendency to improve over time.

Implications relate to the Inhabitance Paradox and Gaian bottleneck concepts.

Abstract

In this paper we introduce some simple models, based on rolling dice, to explore mechanisms proposed to explain planetary habitability. The idea is to study these selection mechanisms in an analytically tractable setting, isolating their consequences from other details which can confound or obscure their effect in more realistic models. We find that while the observable of interest, the face value shown on the die, `improves' over time in all models, for two of the more popular ideas, Selection by Survival and Sequential Selection, this is down to sampling effects. A modified version of Sequential Selection, Sequential Selection with Memory, implies a statistical tendency for systems to improve over time. We discuss the implications of this and its relationship to the ideas of the `Inhabitance Paradox' and the `Gaian bottleneck'.