Digital SAT Reading and Writing Practice Question #721

Ecologist G.E. Hutchinson’s "paradox of the plankton" addresses a core contradiction in evolutionary biology. According to the widely accepted competitive exclusion principle, two species competing for the exact same resources cannot coexist stably; eventually, the one with the slight edge will outcompete and drive the other to extinction. Yet, open-water ecosystems teem with dozens of phytoplankton species that share identical fundamental niches (light, water, and basic nutrients). Hutchinson hypothesized that these ecosystems are so highly dynamic—with chaotic seasonal shifts, turbulent currents, and fluctuating temperatures—that the environment never remains stable long enough for any single species to achieve total dominance. Thus, competitive exclusion is perpetually interrupted, paradoxically sustaining massive biodiversity. Which finding, if true, would most directly challenge Hutchinson's hypothesis?