Citation
On the Evolution of Photoreceptors and Eyes
TL;DR
Eyes evolved independently at least 40 times across animal phyla
This landmark review estimated that eyes have evolved independently at least 40 times across animal phyla, documenting the diversity of eye types (compound, camera, pinhole) and their independent origins. It established the eye as the canonical example of convergent evolution.
The paper demonstrates that when functional constraints are strong (the physics of image formation), convergence is inevitable across vastly different lineages. This principle applies to business: when economic physics strongly constrain solutions, independent companies will arrive at similar models.
Key Findings from Salvini-Plawen & Mayr (1977)
- Eyes evolved independently at least 40 times across animal phyla
- Multiple eye types exist: compound, camera, pinhole
- Physical constraints of optics drive convergence on similar solutions
- Camera eyes evolved at least twice (vertebrates and cephalopods)