Question

Propose what specific cellular and/or genetic changes might have occurred in this extinct bat to create these phenotypic changes (longer body, 6 limbs, colored wings).

Answer 1

Phenotypic variation within a population or between closely related populations can be extrapolated to explain evolutionary trends over longer phylogenetic distances and especially the generation of novel structures.
Several morphological changes were required to derive the bat wing from its ancestral form, including increasing the membrane surface area between the digits and between the forelimb and flank, reducing thickness of cortical bone to decrease weight and torsional stresses increasing the strength and mass of anterior forelimb muscles and rerouting innervation to control powered flight. In addition, the ability of the bat’s wing to provide sufficient lift for flight requires the increased length of skeletal elements relative to ancestral forelimbs.
Molecular changes contributing to: the formation of the bat wing membrane, the elongation of skeletal elements of the bat wing and the reduction of the bat ulna. The general picture emerging from this research is that small changes in the expression of genes critical to many aspects of development have driven large changes in bat wing morphology.