Question

Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?
A) homologous; homologous
B) analogous; homologous
C) homologous; analogous
D) analogous; analogous

Answer 1

Answer:

C) homologous; analogous

Explanation:

The relationship between of the bones in the forelimbs of penguins and seals is a homology.  

Homology is the  shared ancestry between a pair of structures - in this case the forelimbs- in different taxa - in this case penguins and seals-. The forelimbs of vertebrates is a common example of homologous structures because they derived from the same ancestral tetrapod structure.

On the other hand, the relationship between the pinguins flippers and the seals flippers is an analogy.  

Structures of two different organisms with similar functionsare analogus if they are similar  in function  - in this case for swimming- due to convergent evolution but not due to common ancestry. Pinguins flippers and  seals flippers have similar function but different ancestry, therefore they are analogous structures.