Larval flies (maggots) express the Ubx gene in all of their segments and thereby lack appendages. If this same gene continued to be expressed throughout subsequent developmental stages, except in the head region, and if the result was a fit, sexually mature organism that still strongly resembled a maggot, this would be an example of
A) exaptation.
B) homochrony.
C) paedomorphosis.
D) adaptive radiation.

Question

Quizplus · Accepted Answer

This is an example of paedomorphosis, which is the retention of juvenile traits in adults of a species. In this case, the continued expression of the Ubx gene results in the adult fly resembling a larval form, which is a juvenile trait. Exaptation refers to a structure or trait evolving for one function and later being co-opted for another function, homochrony refers to changes in the timing of developmental events, and adaptive radiation refers to the diversification of a group of organisms into different forms and functions to exploit different ecological niches. None of these concepts accurately describe the scenario presented in the question.

Larval Flies (Maggots) Express the Ubx Gene in All of Their