Tuesday, September 23, 2014

Evolution and the Eye

I was watching a video in my biology class about Darwin and his ideas about evolution. The video described how creationists had tried to use the eye as evidence of a supreme creator, because how else could something so complex and perfect evolve from something so simple? This problem even stumped Darwin and in his book “Of the Origin of Species” he even outlined a few steps as to how he thought the eye might have evolved from a simpler form. Even scientists had trouble tracking the path that brought the eye to where it is today, because soft tissues such as the eye don’t usually fossilize. But evolutionists have since been able to challenge the creationists argument all thanks to the blind spot. The fact that there is a blind spot just proves that the eye is not a perfect organ. When something evolves it can only go off of what is already there and that is why it is not perfect. The video described some example of the imperfections in the eye. The optic nerve in our eye evolved to connect to the brain by a small hole in the retina, and this small hole is what causes a blind spot near the center of our eye sight. Another example of an imperfection is the fact that the blood vessels and nerves in the eye sit right in front of the retina, and this makes images less sharp, because it interferes with the way the light reaches the optic lense. The last example of how the eye did not evolve perfectly that the video described, was how there are two layers of the retina the top layer, which collects light, and the darker layer the lines the back of the eye. The imperfection here is that these two layers are not connected and so as we age we can actually have a retinal tear. This causes the liquid in the eye to fill the hole in between the two layers, this can cause retinal detachment and even blindness. I thought that this was a very interesting video and I liked how the eye was connected to an argument between creationism and evolution, and I liked learning that the eye really isn’t perfect and how it might have evolved from just a few light sensitive cells millions of years ago.
(This is the video but forward it to about four minutes in)

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