Great Oxygenation Event
The Great Oxygenation Event represents punctuated pressure - sudden, dramatic environmental shifts that transform fitness landscapes overnight.
Selection pressure doesn't ask permission. It doesn't warn you. It doesn't care about your previous optimization.
2.4 billion years ago, cyanobacteria evolved photosynthesis. They consumed carbon dioxide and produced oxygen as waste. For hundreds of millions of years, oxygen levels rose slowly as dissolved iron and sulfur absorbed it.
Then the oxygen sinks saturated. Atmospheric oxygen spiked from near-zero to 10% - a transformation that unfolded over approximately 200 million years (geological instants relative to Earth's 4.5 billion year history). Every organism on Earth faced new selection pressure: adapt to oxygen or die.
Most organisms died. Oxygen was toxic to anaerobic life, which had evolved for 1.4 billion years in an oxygen-free world. The Great Oxygenation Event was a mass extinction.
But some organisms adapted. They evolved cellular machinery to tolerate oxygen, then to use it. Oxygen enables aerobic respiration, which produces 16 times more energy per glucose molecule than anaerobic respiration. Aerobic organisms could grow larger, move faster, and dominate new niches.
Business Application of Great Oxygenation Event
The Great Oxygenation Event represents punctuated pressure - sudden, dramatic environmental shifts that transform fitness landscapes overnight. COVID-19 was a business Great Oxygenation Event compressed into weeks. Selection pressure doesn't ask permission, warn you, or care about your previous optimization. When the environment shifts, the fitness landscape transforms. Last year's apex predator becomes this year's fossil.