The reverse claim that's actually correct
Most people who hear "DNA is code" assume it's a metaphor — programmers borrowing biological language to make their work sound deeper. The reverse is closer to true. Object-oriented programming is a tiny human discovery of a structural pattern that biology has been running for 3.8 billion years. The OO concepts (class, instance, inheritance, polymorphism, encapsulation) were named by computer scientists in the 1960s-1970s. The patterns themselves predate humans entirely.
The right framing isn't biology is like code. It's both biology and code are running the same architectural pattern, because the pattern is what works when you need to build complex systems out of replaceable parts. The universe figured it out in molecules; we re-figured it out in software.
What the words mean, in biology
- Class. A species. House cat (Felis catus) is a class. It defines the structure: four legs, claws, whiskers, certain DNA, certain instincts.
- Instance. A specific cat. Your neighbor's tabby is an instance of the house-cat class. So is mine. Both share the class structure; both have unique state (this cat is hungry, that cat is asleep).
- Inheritance. Cats inherit from Felidae (the cat family), which inherits from Carnivora, which inherits from Mammalia. Each level adds traits the previous level didn't have but kept the ones it had. Mammals have all Vertebrata traits plus mammary glands. Carnivores add meat-eating teeth. Cats add retractable claws.
- Encapsulation. A cell membrane is encapsulation. The internal state of the cell is hidden from the outside; you can only interact through the surface receptors (the public interface). Same with organs, organisms, ecosystems.
- Polymorphism. Different species solving the same problem with the same interface. Birds, bats, insects all fly — same method (flight), different implementations (feathered wing, leathery wing, chitinous wing). Coming up in lesson 4.
Why this is more than wordplay
Once you start seeing biology as OO, several things become clearer:
- Why is taxonomy hierarchical? Because inheritance produces hierarchies. The Linnean tree-of-life (kingdom → phylum → class → order → family → genus → species) is a class hierarchy, drawn from the inheritance pattern in DNA.
- Why do cells, organs, organisms, and ecosystems all show similar coupling-and-cohesion patterns? Because at every layer the universe is using the same architectural primitive — encapsulated objects with public interfaces.
- Why does AI architecture (especially modern neural networks) feel biology-shaped? Because we're using the same primitives: encapsulated layers, message passing, learned interfaces. The OO substrate is the same.
This whole track is one move: see biology with OO eyes. Once you do, evolution stops being a slogan and becomes a precise architectural process. The next four lessons sharpen each part.