Red Sea Urchin

Red sea urchins are the prey that sea otter keystone predation controls. Without otters, urchin populations explode and devour kelp forests, creating 'urchin barrens'—underwater deserts where nothing grows. The urchin itself isn't doing anything different when controlled by otters versus when running unchecked; it's the presence or absence of the keystone predator that determines ecosystem outcomes.

This creates a fascinating dynamic: urchins are simultaneously essential ecosystem components (controlled populations graze algae that might smother kelp) and ecosystem destroyers (uncontrolled populations eliminate kelp entirely). The same organism plays hero or villain depending on top-down control.

The business parallel is unchecked intermediaries that extract ecosystem value. Urchins are like toll-takers, aggregators, or middlemen whose activity is beneficial when moderated but destructive when unchecked. A payment processor that takes 2% facilitates commerce; one that takes 40% destroys it. Real estate brokers, talent agencies, and platform fees all follow similar dynamics. Sea otter predation shows that some ecosystem participants need external control—they lack internal regulation that prevents overexploitation.