This is the first time I ask anything on this forum.

Does anyone know what the precise meaning of "biological role" is?

I recently was told that "performance" is the "ability to carry out a biological role".  So what is a biological role then?

Can things like "biting" or "walking" be a biological role?  Or is that a "performance"?

If these kind of things are "performances" then what are the "biological roles" that they are carrying out?

I am as puzzled as you Manabu.

As a molecular and cell biologist I think of a biological role in terms of the function of a gene, protein, cell, system etc. I can't think of a circumstance where I would term biting or walking as a biological role - they are to my mind functions or activities. Similarly, I am not at all clear what the word "performance" means or adds to the context we are discussing.

It's a new one on me and I try and keep up with the ecological and behavioural literature and I don't recall having seen anything like that there.

huh - so I guess it's a more biomechanics/functional morphology term.

I had a long thought about this and I am guessing that the "biological role" of jaws would be to "kill/process prey".  And the "ability to carry out this role" (performance) is the act of biting.  So biting is a performance.  Things like "bite force" or "mechanical advantage" quantify this performance so they would be a form of "performance measure" or "performance metric".  Or so I think...

I've always thought (I don't know how correctly) of "biological role" and "function" as more or less synonymous. So yes, the biological role of jaws is to kill and process prey. To me the phrase "a performance" has the connotation of a display intended to be perceived by others, whereas "performance" (without the indefinite article) is basically a synonym of "ability"; thus one can refer to "biting performance" or "running performance", either of which could indeed be quantified by various kinds of performance metric. I would refer to biting as an action, activity or behaviour.

I should make it clear that I'm only describing my subjective understanding of these various terms, not putting forward "THE correct definitions"!