Fig. 1

 A schematic of the Avida world and its constituent organisms. a The Avida world consists of a 2D grid of lattice sites where organisms can reside. Each organism (e.g. the white dot) has eight nearest neighbors (and corresponding lattice sites, denoted by green dots) to whom it can send messages or replace with its offspring. The world is periodic, with the horizontal and vertical boundaries coinciding with their opposites (red boundary on red, yellow boundary on yellow). b Each organism consists of a genome containing 120 genomic instructions which are read and executed by a “virtual CPU”. c This virtual CPU reads the genome instruction by instruction, gets inputs from the environment and processes them using the genomic instructions to generate an output. It can also read and write instructions using the read (R) and write (W) heads in order to copy the genome before division