The key in providing such an explanation, say evolutionists, is two-fold. First, they needed the detailed account of how vision works at the molecular level. These details have been increasingly elucidated in recent decades and they are crucial in understanding the evolutionary steps that led to the eye.
Second, they needed a better understanding of the evolutionary tree, telling them which species evolved from which. This provides the framework from which to derive the sequence of molecular changes that led to the eye.
With these two developments well in hand, evolutionists have now laid out what was once thought impossible. They have derived a detailed account, at the molecular level, of vision. They have discovered how chance mutations could spontaneously create the eye. They now have the holy grail.
And as is sometimes the case with the greatest scientific breakthroughs the answer turns out to be rather simple. Newton explained that F=ma and Einstein found that E=mc^2. Now we have an even more profound discovery. The incredible cellular signal transduction cascade at the heart of vision evolved from a similar system in yeast. Yes, believe it or not, it is that simple. As the evolutionists explain:
In yeast (a fungus), these receptors are sensitive to pheromones, and they even direct a signal through proteins homologous to non-opsin phototransduction proteins. As such, a signaling pathway exists outside animals, which is very similar to phototransduction, except that the receptor protein detects pheromones, not light. Receptors outside animals share some characteristics with opsin, like snaking through a cell membrane seven times. It is one of these serpentine proteins that served as the progenitor of the first opsin protein, as evidenced by the similarity of opsins and other serpentine proteins.
There you have it. The eye evolved from a signaling pathway outside of animals. The evolutionists triumphantly conclude that:
the gap in understanding of the molecular evolution of eye components is all but closed, highlighting the bankruptcy of the argument that design is required to explain the origins of biological features
What is perhaps most remarkable about this finding is the sheer genius of evolutionists. This is just the stuff of good solid scientific research and once again we’re reminded of why evolution is such an undeniable fact.
Now the evolutionists admit they haven’t figured out every last detail—such as how the yeast system arose in the first place or exactly which mutations morphed it to the animal vision system—but those are details. As you can see, they’ve answered the big questions.
The evolution of the eye, a problem that once made Darwin shudder, is now obviously solved.