Ichthyosaurs

Physics dictates strategy. Three lineages separated by 350 million years of evolution—fish, reptiles, and mammals—converged on the same torpedo body shape. Not because they copied each other, but because hydrodynamics offers exactly one solution to the problem of fast swimming.

Ichthyosaurs dominated Mesozoic oceans for 160 million years, from 250 to 90 million years ago. These air-breathing reptiles evolved from land-dwelling ancestors, yet within 40 million years achieved a body form nearly identical to modern dolphins. Both groups developed dorsal fins for stability, lunate tail flukes for propulsion, and streamlined fusiform bodies to minimize drag. The convergence extends to physiology: isotope analysis suggests ichthyosaurs were warm-blooded, maintaining elevated body temperatures just as dolphins do.

The physics is unforgiving. Drag increases with the square of velocity. Any deviation from the optimal 4.5:1 length-to-width ratio measurably reduces speed and efficiency. Dolphins, tuna, and ichthyosaurs all cluster around this ratio. Evolution ran the same experiment multiple times across hundreds of millions of years and got the same answer.

The ichthyosaur phenomenon plays out wherever physics or economics creates tight constraints. Budget airlines from different continents—Ryanair in Europe, Southwest in America, AirAsia in Southeast Asia—converged on nearly identical operating models despite no coordination. All discovered the same optimal form: point-to-point routes, single aircraft types, no frills, maximum seat utilization. The economics of low-margin air travel imposes constraints as unforgiving as hydrodynamics.

The same logic explains why Aldi and Trader Joe's, founded independently on different continents, converged on the same 1,500-SKU format with private labels dominating shelf space. When margins are thin and competition intense, the selection pressure squeezes out variation. Silicon Valley and Shenzhen independently evolved similar startup ecosystem structures—accelerators, angel networks, venture capital staged financing—because the economics of high-risk technology investment creates a single-peak fitness landscape.

Convergent evolution reveals something profound about fitness landscapes. When constraints are strong and trade-offs few, all competitors converge on the same peak regardless of starting point. Ichthyosaurs started as land reptiles; dolphins started as land mammals. Neither had any knowledge of fish body plans. Yet both arrived at the same destination because physics left no alternative.

Selection pressure explains the precision. In environments where a 10% efficiency difference means the difference between catching prey and starvation, natural selection tolerates no deviation from optimal. The same pressure acts in commodity businesses—a grocery chain with 2% higher costs than Aldi simply cannot survive at Aldi's price points.

Ichthyosaurs teach the unsettling truth that many strategic choices aren't really choices at all. When constraints are tight and stakes are high, there's only one viable form—and every competitor will find it. The question isn't whether to converge, but whether you're converging fast enough.