The Watchmaker: my fav argument

[polymath257]

These days, the term 'theory' is mostly used for an attempt to unify a large collection of phenomena in a single system.

Right. Theories tend to either provide unification, or give a casual account of things. And perhaps the distinction is most notable across disciplines than within disciplines. Physics seems more interested in unification, thus you have things like the "theory of everything." But biology is more interested in casual theories. Thus why evolution explains the diversity of life on earth as resulting from changes in allele frequencies.

One difference is that biology uses the sciences of physics and chemistry in its explanations of how genes work.

Note: you should also include natural selection as one of the causal aspects of evolutionary theory.

I'm always a bit suspicious of the term 'cause'. For example, quantum mechanics isn't causal in any classical sense. But when it is averaged over Avogadro's number of atoms, the average is precisely predictable. I know, it's a quibble, but a descriptive theory need not be causal and causal theories tend to be based on more fundamental theories.