Rattling Around

Ah, so where does Intelligent Design (ID) fit into all this? One of the arguments for ID is that the eye is too complex to have happened by chance. But not all eyes are designed alike! For example, the octopus eye is quite different from the usual eye of a mammal (such as humans). Both eyes are more or less round, with a retinal layer of receptors (rods and cones). Both have blood vessels nourishing the retina, and have nerve cells to connect the receptors to the brain. In the octopus, those vessels and nerves are in back of the receptors, out of the way, and the receptors point towards the light coming into the eye. But in mammals, it's backwards, with the blood vessels and nerves blocking some of the light from getting to the receptors. And since your brain is not inside your eyeball, the optic nerve has to leave the eyeball to get to the brain. That exit point can't have any receptors, which is why you have a blind spot in each eye. It certainly seems like that Intelligent Designer liked the octopus better than man, since its eye got a more intelligent design. Makes you wonder...

There are lots of animals with vision advantages compared to humans. Some can see into the infrared and some into the ultraviolet. Some can see light polarization (without wearing special sunglasses). And of course there are other senses that detect electric fields (sharks), magnetic fields (birds), temperature differences (rattlesnakes), pressure changes (fish), sonar echoes (bats and dolphins), seismic vibrations (antlions). Even plants have senses (light, gravity, etc.). I do have some ideas on why humans are special, though. Maybe in a later post I'll write about them.