This lesson introduces the competitive exclusion principle, its historical development, and the classic experiments that helped establish it. Understanding the principle provides a foundation for explaining how competition can shape populations and ecological niches.
The competitive exclusion principle, sometimes called Gause's law, proposes that two species competing for the same limited resource cannot coexist indefinitely at constant population sizes when ecological conditions remain constant. If one species has even a small advantage, it may eventually dominate.
All flashcards
Competitive exclusion principle
The prediction that species competing for the same limiting resources cannot maintain stable coexistence indefinitely under constant conditions.
Complete competitors
Species with sufficiently overlapping resource use that they lack a meaningful difference permitting stable coexistence under the prevailing conditions.
Gause's Paramecium experiments
Laboratory competition experiments in which P. aurelia excluded P. caudatum under particular conditions.
Competition–colonization trade-off
A pattern in which strong competitive ability and effective colonization ability occur in different species.
Phylogenetic limiting similarity hypothesis
The prediction that species with similar functional traits and resource use may compete more strongly.
Quiz questions
What does the paradox of the plankton describe?Answer: Many plankton species coexist in small areas despite relying on an apparently limited set of resources.
What characterizes a competition–colonization trade-off?Answer: Strong competitors and effective colonizers are not necessarily the same species.
What does phylogenetic overdispersion describe?Answer: Co-occurring species are more distantly related than expected.
How can environmental filtering contribute to phylogenetic clustering?Answer: Conditions favor shared, conserved traits that occur among related species.
How can a time lag affect the apparent outcome of competition?Answer: Species may coexist temporarily before eventual exclusion becomes apparent.