| Popis: |
Regulation of population size is described for 2 protozoan species in environments that become progressively more variable in time. The ciliate, Colpidium campylum, rapidly adjusts pop- ulation levels to fixed equilibria set by bacterial food supply. As the equilibrium is varied more frequently, tracking populations of this species destabilize and eventually become extinct. A much larger species, Paramecium primaurelia, regulates slowly to fixed equilibria but assumes more even densities in variable environments. Effects of changing environments are determined here by the frequency and not the magnitude of changing equilibria. |
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