Evolution doesn’t build from scratch. It remodels. The technical term is neofunctionalization: taking a structure that already exists and repurposing it for a new job.
Examples:
- Lobe-finned fish already had radius, ulna, digits inside fleshy fins → bones thickened, muscle attachments evolved → legs
- Lungs evolved 420 million years ago as gut pouches for gulping air in low-oxygen water → repurposed for land breathing
- Swim bladders (fish buoyancy organs) are neofunctionalized lungs — not the other way around. Lungs came first. Fish that lost lungs repurposed them for buoyancy
- Keratin existed inside cells as structural scaffolding → cells stuffed more in to retain water → cells died filled with keratin → waterproof outer layer
The last one is remarkable: internal support beams became outer armor. The same molecule, same cell, radically different function.
Broader principle: Constraints breed creativity through constraint — when you can’t build from scratch, you work with what’s there. The resulting solution is often stranger and more elegant than anything designed from the ground up would be.
Sermon/theology connection: Restoration theology uses the same logic. God works with what’s there — broken human lineages, fallen cultures, flawed instruments — and repurposes them for providence. The cross itself is neofunctionalization: defeat repurposed as victory.
Air breathing re-evolved dozens of times independently — convergent evolution finding the same solution from different starting points.