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.

Answer 1

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

Reason: a "derived" trait is one that evolved later relative to an ancestor. If spiders (eight legs) are ancestral, the six-legged condition in insects would be the derived change.