Although birds and bats have a similar forearm, their wings are quite different. A bird wing is covered in feathers that are attached to the arm. A bat wing is made from skin that is attached to the arm and between each finger bone. The graphic shows the two wing types.

Question

The left illustration shows a bat wing with an arrow labeled 'skin' pointing to the middle of the wing. The right illustration shows a bird wing with an arrow labeled 'feathers' pointing to the middle of the wing.

Which option BEST describes the evolution of these features of bats and birds?

A. 
The forearms of birds and bats are similar in structure, so this feature did not come from a common ancestor. The wings of birds and bats are not similar in structure so this feature came from a common ancestor.

B. 
The forearms of birds and bats are similar in structure, so this feature came from a common ancestor. The wings of birds and bats are not similar in structure so this feature did not come from a common ancestor.

C. 
The forearms of birds and bats are similar in function, so this feature came from a common ancestor. The wings of birds and bats are not similar in function so this feature did not come from a common ancestor.

D. 
The forearms of birds and bats are not similar in function, so this feature did not come from a common ancestor. The wings of birds and bats are similar in function so this feature came from a common ancestor.

GPT-4o mini · Answer

The best option to describe the evolution of the forearms and wings of bats and birds is:

B. The forearms of birds and bats are similar in structure, so this feature came from a common ancestor. The wings of birds and bats are not similar in structure so this feature did not come from a common ancestor.

This option highlights the shared structural similarity of the forearms (which indicates a common ancestry) while recognizing that the wings themselves have evolved different structures (feathers in birds and skin membranes in bats) independently, which reflects convergent evolution rather than common ancestry for the wings.