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:

• Option 1: Spiders do have eight legs. This is a well - known fact in biology, so this option is incorrect.
• Option 2: Insects are defined by having six legs. This is a fundamental characteristic of insects, so this option is incorrect.
• Option 3: In evolutionary terms, if spiders (with eight legs) evolved first, then the trait that is different (six legs in insects) is the derived trait. A derived trait is a trait that has evolved from an ancestral form. If the ancestor (spiders in this incorrect evolutionary assumption) had eight legs, then the six - legged condition in insects is the new (derived) trait.
• Option 4: Spiders do have derived traits. Derived traits are not exclusive to non - ancestral groups. For example, spiders have other unique characteristics (like spinnerets for making webs) that are derived traits.

Answer:

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