Question

1 what is similar and different about the three forelimbs? what type of structures are represented above? (2pts)
2 to which of the three structures would a dragonfly wing be analogous?
3 define the terms homologous structure, analogous structure, and vestigial structure. (3pts)
4 what do the bone structures indicate about the ancestry of humans, whales and bats?

Explanation:

1. Similarities: All three forelimbs (human, whale, bat) have the same basic bone structure (humerus, radius, ulna, carpals, metacarpals, phalanges). They are homologous structures as they share a common evolutionary origin. Differences: Their functions are different - human for grasping, whale for swimming, bat for flying.
2. A dragonfly wing would be analogous to the bat's wing. Analogous structures have similar functions (flight) but different evolutionary origins.
3. - Homologous structure: Structures that have a common evolutionary origin but may have different functions (e.g., human arm, whale flipper, bat wing).

• Analogous structure: Structures that have similar functions but different evolutionary origins (e.g., dragonfly wing and bat wing).
• Vestigial structure: Structures that have lost most or all of their original function through evolution (e.g., appendix in humans).

1. The similar bone structures indicate that humans, whales, and bats share a common ancestor. Homologous structures suggest evolutionary relatedness.

Answer:

1. Similar: same basic bone structure. Different: functions. Homologous structures.
2. Bat's wing.
3. Homologous: common origin, different functions. Analogous: similar function, different origin. Vestigial: reduced/functionless.
4. Common ancestor.