Long before forests or mammals, the oceans were laboratories. From soft-bodied swimmers to armored giants, fish evolution traces the first great vertebrate experiment in movement, perception, and survival.
Fish Evolution
Vision Emerges: The Pre-fish Chordates
540 Mya
Vision Emerges; Proto-Simple Brains; Pre-vertebrate Cord.
Simple Sentience Settles: Haikouichthys
520 Million BCE
Simple Brains; Proto-Short-Term Memory; Simple Sentience.
Keratin Genes & the Rise of Scales in Fish
425 Million Years Ago
425 MYA (+/- 15 Million Years)
Lungs Evolve: Lobe-Finned Fish and the Lungfish Ancestor
400 Million BCE
The Senegal Bichir: A Living Fossil
~380 million years ago (± 15 million)
Air breathing lungs and lobed pectoral fins
Long-Term Memory Evolves: Tiktaalik
375 Mya
Complex Brains; Long-Term Memory; Simple Sentience.
Stem Selachians: Modern Sharks LCA
~300 million years ago (± 10 million years)