Comparisons of 154 genomes from 21 animal phyla and outgroups have been used to reconstruct ancestral adaptation to life on land across 11 distinct terrestrialization events, revealing strong evidence for convergent genomic evolution across the animal kingdom and recurring periods of terrestrial colonization.

Vertebrate eyes first evolved in water, where spectral content rapidly fades with distance. Zebrafish exploit this loss by antagonizing cone signals to suppress the background, pointing to distance estimation—rather than color—as an ancestral cone function.