Question 15

The shared characteristics are not all present in any single ancestor of these three arthropod groups.

The author suggests that the shared characteristics among insects, crustaceans, and other arthropods do not stem from a single common ancestor, indicating a more complex evolutionary relationship.

A) Insects and crustaceans each have unique limb form, musculature, and embryonic development.

This statement is incorrect because it implies that the unique features of insects and crustaceans negate the existence of shared characteristics. The passage indicates that, while they may have unique traits, they also share certain characteristics that do not originate from a single ancestor.

B) The shared characteristics are not all present in any single ancestor of these three arthropod groups.

This option accurately reflects the author's viewpoint. The author argues that the characteristics shared among the groups cannot be traced back to one common ancestor, suggesting that evolutionary pathways diverged in ways that do not support a singular lineage.

C) The shared characteristics are a good indication that all three groups of arthropods are most closely related.

This statement is misleading. The author implies that while there are shared characteristics, they do not necessarily indicate a close evolutionary relationship due to the absence of a singular ancestor that embodies all these traits.

D) The shared characteristics do not justify classifying all three animal groups as arthropods.

This option misrepresents the author's intent. The shared characteristics do play a role in classifying these groups as arthropods, but the author emphasizes the complexity of their evolutionary origins rather than outright dismissal of their classification.

E) The shared characteristics are the most compelling evidence to date for the theory of convergent evolution.

This statement is incorrect as it suggests that the shared characteristics support convergent evolution, which typically involves unrelated species developing similar traits. The passage implies that the shared traits arise from a more intricate evolutionary history rather than merely convergent evolution.

Conclusion

The correct answer, option B, effectively captures the author's argument that the shared characteristics among these arthropod groups do not derive from a single ancestor. This contrasts with the other options, which either misinterpret the relationship between the characteristics and classification or contradict the author's perspective on evolutionary lineage.