Historical fallacy

Biological Parallel

Exaptation demonstrates that historical origins don't constrain current utility. Feathers evolved for thermoregulation in dinosaurs but modern birds use them for flight. Mammalian ear ossicles (malleus and incus) were exapted from dense reptilian jaw bones—fragile vibration transmitters repurposed from structural supports. Swim bladders evolved from respiratory organs into buoyancy control. A 2025 study found 6% of the human genome shows enhancer turnover, with 80% arising from repurposing existing enhancers for novel regulatory functions. The panda's 'thumb' is a wrist sesamoid bone originally for climbing that became a bamboo-grasping tool—exaptation, not original design. Natural selection optimizes for present fitness, indifferent to historical purpose. Function shifts constantly.