Ribosome Evolution

The ribosome — life's universal protein factory — is itself a ribozyme. The peptidyl transferase center (PTC), a pure rRNA structure, catalyzes peptide bond formation. Proteins were added later.

Evolutionary Layers (Bokov-Steinberg Model)

Animation

What you're seeing:
Concentric rings = evolutionary age
Inner = ancient (>3.8 Gya)
Outer = modern additions

The PTC core (center) has changed almost nothing in 3.8 billion years.

Key insight: The ribosome proves RNA World. It's a machine made of RNA that makes proteins — including the proteins that eventually joined it. The ribozyme built its own successor.