"Co-option and exaptation refer to biological structures that supposedly evolved in a response to selective pressures for one function, and then were co-opted by evolutionary processes to have a different function.
For instance, one theory of bird-wing origins is that wings evolved in order to make birds seem larger and more ferocious, and these were subsequently ‘recruited’ by later evolutionary processes for flight.
We hear that irreducible complexity is not real because the components of a complex system can each have alternative functions.
We hear that irreducible complexity is not real because the components of a complex system can each have alternative functions.
This confuses the issue, which is not the function of a component itself, but how the function of the entire system could arise step by step.
---For instance, the spring in the mousetrap, acting alone, can be used
in many different devices.
Fair enough. However, the ‘springiness’ of the spring is not the essence of the mousetrap—it is the unique configuration of all the components of a mousetrap, including the spring, that enables it to function as a mousetrap.
That is what needs to be explained by evolution.
Bergman touches on some of the challenges facing a putative evolutionary explanation, for the origins of complex structures, resulting from the co-option of components originally having different functions. He comments:
“… the availability of these parts would have to be synchronized … the parts must be correctly and properly positioned in 3-D space so they can be properly assembled … . Even if all of the parts are available at the proper time, the vast majority of assembly variations will be non-functional or dysfunctional” (pp. 145–146).
So the irreducible complexity remains."
Bergman touches on some of the challenges facing a putative evolutionary explanation, for the origins of complex structures, resulting from the co-option of components originally having different functions. He comments:
“… the availability of these parts would have to be synchronized … the parts must be correctly and properly positioned in 3-D space so they can be properly assembled … . Even if all of the parts are available at the proper time, the vast majority of assembly variations will be non-functional or dysfunctional” (pp. 145–146).
So the irreducible complexity remains."
CMI