Simple Bit-String Model for Lineage Branching

TL;DR

This paper presents a simple bit-string population model demonstrating how lineage branching and scale-free distributions emerge from mutation and selection dynamics, providing insights into paleoevolution patterns.

Contribution

Introduces a novel population dynamics model using bit-strings to simulate lineage branching and scale-free behaviors in evolution.

Findings

Lineage duration and size distributions follow scale-free patterns.

The model reproduces power-law behaviors observed in paleoevolution.

Simple mutation and selection rules can explain complex evolutionary phenomena.

Abstract

We introduce a population dynamics model, where individual genomes are represented by bit-strings. Selection is described by death probabilities which depend on these genomes, and new individuals continuously replace the ones that die, keeping the population constant. An offspring has the same genome as its (randomly chosen) parent, except for a small amount of (also random) mutations. Chance may thus generate a newborn with a genome that is better than that of its parent, and the newborn will have a smaller death probability. When this happens, this individual is a would-be founder of a new lineage. A new lineage is considered created if its alive descendence grows above a certain previously defined threshold. The time evolution of populations evolving under these rules is followed by computer simulations and the probability densities of lineage duration and size, among others, are computed. These densities show a scale-free behaviour, in accordance with some conjectures in paleoevolution, and suggesting a simple mechanism as explanation for the ubiquity of these power-laws.