Question

When originally classified, whales and hippopotamuses were placed into different orders. Molecular analysis recently suggested that whales (order Cetacea) and hippopotamuses (order Artiodactyla) are extremely closely related, sharing a recent common ancestor.
This has led some taxonomists to create a new phylogenetic tree that puts the two orders together into a single clade. It is still unclear as to whether the whales diverged from Hippopotamuses before or after the divergence of other species in the order Artiodactyla.
An interesting physical feature of whales is the presence of vestigial pelvic bones.
If scientists determine that whales diverged from the artiodactyl order after llamas and giraffes, what should be true of the vestigial pelvic bones of whales?

• A. They are a shared ancestral feature of whales, llamas, and giraffes.
• B. They are a shared derived feature of whales, llamas, and giraffes.
• C. They are a shared ancestral feature of whales.
• D. They are a shared derived feature of whales.

Answer 1

The correct option is D They are a shared derived feature of whales.

The presence of vestigial pelvic bones is a characteristic of whales, even though pelvic bone was present in the species that diverged Hippopotamuses. It was not used in whales and hence vestigial. The bone being vestigial is characteristic of whales

So, the correct answer is 'They are a shared derived feature of whales'