In order to say that some function is understood, every relevant step in the process must be elucidated.

Although Darwin was able to persuade much of the world that a modern eye could be produced gradually from a much simpler structure, he did not even attempt to explain how the simple light sensitive spot that was his starting point actually worked.

Skin is made in large measure of a protein called collagen.

I find the idea of common descent (that all organisms share a common ancestor) fairly convincing, and have no particular reason to doubt it.

In many biological structures proteins are simply components of larger molecular machines.

Biology has progressed tremendously due to the model that Darwin put forth. But the black boxes Darwin accepted are now being opened, and our view of the world is again being shaken.

It is often said that science must avoid any conclusions which smack of the supernatural.