The Eye - The engine of evolution and one of its masterpieces.
See History Channel's "Evolve" where the evolution of the eye is documented from jellyfish that respond to color changes to various animals with eyes evolved to suit their habitat:
Tarsier: Small mammal. Eye as big a brain! Eye is immoble but neck rotates more than 180 degrees! Saw it on the Evolve DVD. Amazing.
Over time eye sockets, channel to brain and skull size increased
Big cats: glowing eyes of cats - Tapedum lucidum
The tapetum lucidum is a reflecting layer immediately behind the retina of the eye of many vertebrates that serves to reflect light back to the retina, increasing the quantity of light caught by the retina 6 times better than human. Primarily found in nocturnal animals with good night vision, such as cats. bottlenose dolphins, dogs, and deer.
The tapetum lucidum is not present in the human eye, which is why humans have poor night vision. But... we have compensations.
One of few species to see full range of color.
Mammals took root after dinosaurs disappear. Can now become "day-active" with fear. Evolve to see "red" in their new world.
Why? What did early primates gain by evolving to see red? Red leaves in the jungle canopy are full of nutrition, younger, more tender.
Ability to see red gives primate ability to go directly to the best food.
Eyes in front of head gives depth perception - needed for jumping from tree to tree.
Gives up panoramic view to see predators. Makes them easy targets for birds of prey.
Formed social groups to improve safety - led to larger, more powerful brains.
Became sensitive to changes of expression in faces of companions.
Visual processing gave rise to intelligence.