Comparative Vertebrate Anatomy Apr 2026

Some of the most compelling evidence for evolution comes from "evolutionary baggage." Vestigial structures are remnants of organs or bones that served a purpose in ancestors but are now useless. Examples include the pelvic bones in whales (remnants of legs) or the human tailbone. Why It Matters Today

These are parts that share a common ancestry but may look different or perform different tasks today. A classic example is the pentadactyl limb . The humerus, radius, and ulna found in a human arm are the exact same bones found in a whale’s flipper and a bat’s wing. They are "variations on a theme." Comparative Vertebrate Anatomy

Fish have a two-chambered heart, efficient for water-breathing. As vertebrates moved to land, hearts evolved into three chambers (amphibians/reptiles) and eventually four (mammals/birds) to keep oxygenated blood separate and support higher metabolic rates. 4. Vestigial Structures: The "Leftovers" Some of the most compelling evidence for evolution