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

Proteins are the machinery of living tissue that builds the structures and carries out the chemical reactions necessary for life.

The basic structure of proteins is quite simple: they are formed by hooking together in a chain discrete subunits called amino acids.

Since natural selection requires a function to select, an irreducibly complex biological system, if there is such a thing, would have to arise as an integrated unit for natural selection to have anything to act on.

In Darwin's time all of biology was a black box: not only the cell, or the eye, or digestion, or immunity, but every biological structure and function because, ultimately, no one could explain how biological processes occurred.

I did my graduate research paper on the biochemistry of schizophrenia . Intellectually , I believe that most serious mental illness has a biological component and that the visible results are partly a personality reaction to a body that can’t be trusted .