Question

mr. morales is teaching a lesson on classification. he says that spiders are classified as a different group than insects because they have eight legs instead of six legs. he explains that spiders evolved first. mr. morales also says that having eight legs is the derived trait that separates the two groups. antonio thinks mr. morales is wrong. which piece of information is antonio considering?
○ spiders do not have eight legs.
○ insects do not have six legs.
○ if spiders evolved first, six legs is the derived trait.
○ spiders do not have derived traits, since they evolved first.

Explanation:

To determine Antonio's consideration, we analyze the concepts of evolution and derived traits. A derived trait is a characteristic that appears in a descendant group and differs from the ancestral form. If spiders evolved first (as Mr. Morales claims), then the ancestral trait would be eight legs (spiders' trait), and the derived trait (newer trait) would be six legs (insects' trait). So Antonio is likely considering that if spiders evolved first, six legs (insects' trait) is the derived trait, which contradicts Mr. Morales' claim that eight legs (spiders' trait) is the derived trait.

• The first option is incorrect as spiders do have eight legs.
• The second option is incorrect as insects typically have six legs.
• The fourth option is incorrect because even if spiders evolved first, they can still have derived traits relative to their own ancestors (not just compared to insects).

Answer:

C. If spiders evolved first, six legs is the derived trait.