Jurvetson on Tadpole:

Frogs have binocular vision to catch flies. Tadpoles have eyes on the sides of their heads, a common difference between predator and prey.

The eyes move halfway through life, and so the visual system in the frog’s brain needs to be rewired. The nerves from half of the tadpole’s eyes must remap to the other half of the brain to properly process the new overlapping field of view.

The ephrin B gene modulates the axon’s growth cone in the optic chiasm (a crossroads junction of sorts) to achieve binocular vision. The same gene serves the same function in mice, but is silent in fish and chicken, which lack binocular vision.