Question

Evelyn is digging in a riverbank on the Peace River. She finds a fossil that looks like whalebone. After further digging, she finds the rest of the skeleton. While putting this skeleton together, she ends up with a few extra bones, including hip and leg bones that were too small for this animal. What would be the possible reason for these bones in this organism?

These bones give molecular evidence for relatedness to other organisms.

These bones are giving evidence to the geographical distribution of this organism.

These bones are vestigial structures showing relatedness to ancestral organisms.

These bones are analogous structures related to dolphin species.

Answer 1

Correct answer: These bones are vestigial structures showing relatedness to ancestral organisms.

Explanation: Small hip and leg bones in whales are vestigial — reduced remnants of structures that were functional in their terrestrial ancestors. This is morphological evidence of evolutionary relatedness (homology), not molecular data (choice 1) or biogeography (choice 2). They are homologous vestiges, not analogous structures (choice 4), since analogous structures arise independently for similar functions rather than from a common ancestor.