Originally posted by dorkus:
There must have been a point at which an animal that we call ape gave birth to an animal that we call man (primitive or whatever). Even more incredibly, this man had to mate and his offspring had to carry and express his genetic traits.
Not exactly correct. It would be more correct to say that at one point, an ape gave birth to an ape with different DNA. That ape had offspring which carried its modified genes. Then, after many, many generations, with
exactly these small steps along the way, one could call the offspring a different species. I see your point, and must agree that any genetic change which impairs the ability to produce offspring will in effect end the line of the host organism. I think you may not grasp the gradual change involved. It didn't go Ape>Human. It went Ape1(for a long, long time)>Ape2(which is only slightly different, and for a long, long time)>Ape3(slightly different)...repeat,repeat,repeat...>Ape"N". At any step, you could choose to compare an ape and the "original," Ape 1, and think "wow, they're so different." With humans, there is literally fossil evidence--you can see the progression from ape ancestor to modern human. You're just disregarding the immense time required, and the gradual nature of change.
Evolution is filled with these ludicrous steps. Consider, for example, the evolution of an eye. You have to have an eyeless animal give birth to an animal with a functional eye(s) to make any evolutionary sense. -The supporting skeletal structure and muscles, the lens, the retina, the optic nerve, the connection to the brain, etc. - the list is endless. Miss one of those parts and you just have an ugly blob on the face of an organism that no other organism is going to want to reproduce with. (I know, I know, they can't see it - but you get the point). When you consider the incalculable odds (easily statistically impossible), I'd say we've got a miracle.
The eye has been used as an example for years by those who wish to ignore the evidence showing that evolution occurs. It has been disproven time and time again. Please
see this webpage, which addresses a typical related misquotation of Darwin's own writing, and
watch this video from a PBS special which talks about experiments in modeling the evolution of the eye.
This site, written by a Stanford researcher , describes in detail the structures of the eye and the various forms of light-detecting organs in the world today.
Your argument is a bit flawed. You assume that all the structures peripheral (no pun intended) to the eye itself must be there for the eye to work. You're incorrect. Those structures simply
are there in human eyes. Consider the following:
The planet Earth is bathed in radiation from the sun. Much of this radiation reflects quite predictably from objects on Earth (specifically within the part of the spectrum called "visible light.") The first optic organs were most likely single cells which could only detect light or dark (there are still organisms with these organs). The ability to detect movement would have been next (this would involve only simple optic cells, and furthermore, would have given a great advantage to organisms who could detect predators). The formation of the lens would have occured next, beginning with a simple layer of enzyme to aid in focusing. We're still at a relatively simple stage in development. Next would come things like distance detection (which would require a more specialized lens) and color detection. The structures around these primitive eyes would have been equally primitive, but as detection of optical phenomena became more and more helpful to organisms, the structures supporting those eyes would also have evolved to become more robust.
As an aside, consider the flaws inherent in the human eye. Blood vessels run across its surface, making it delicate, and the location of the optic nerve within the eye itself causes a "blind spot." Haven't you ever done the optical trick with two dots which shows you quite clearly where your blind spot is? My point is that if the human eye was designed, it could have been designed better.
Here's one for you. If you look at a plot of sensitivity of the human eye to different colors, the human eye has the strongest sensitivity to a green-yellow color at a particular wavelength. If you then look at a spectral plot of the luminance of the sun, there is
exactly the same spike at that wavelength. The sun gives off visible radiation most strongly in the yellow-green region, and because our eyes evolved on this planet, the human eye shows greatest sensitivity to that color exactly.
Don't believe me? Buy two laser pens of exactly the same wattage--one red, one green. Despite the fact that they use the same batteries and draw the same power, the green one will appear "brighter." This is a direct result of the evolution of the eye on our planet.
Nick, I'd love to hear your several plausible theories of how life started. Aliens? So far I've seen evolution and something involving a higher power. I believe most choose evolution for the simple reason that they don't want to acknowledge a higher power. But isn't evolution just too incredible left alone? At least give me that you see my point.
And many choose the higher power out of a lack of understanding. Evolution occurs. You cannot dispute this. Bacteria develop resistance to medications, case in point. Where we can debate, however, is how life started. I admit, I am certainly no expert in organic chemistry, but there is evidence for the formation of replicating chains of amino acids from raw molecules. There is, however, no such evidence of aliens depositing a fully-functional cell on Earth. I choose to believe that which has been supported by evidence. That doesn't mean the theory of alien-depositing is
disproven, it just means it's less likely than abiogenesis.
Similarly, I don't think anything "disproves" the possibility of a "higher power." But I will not ignore evidence that suggests that evolution explains the origin of species. If another sentient being "caused" the beginning of our universe, I'd love to have a beer with them and talk.