EEB 2244 Competition Fall 2014 Competition is the ___exploitation__of a resource by an____individual____ that results in that resource being____less____available for another individual. Intraspecific competition is competition among individuals of______________________________ species. Interspecific competition is competition among individuals of______________________________ species. Some examples of competition: -growing a garden closely packed together doesn’t thrive as well as evenly spread apart -elephants Competition is a primary organizing ecological process that controls the composition of natural communities. Applications include____________management_________ of agriculture,________forests_________ , and_______wildlife and natural resources___________ . Competition Experiments Competition experiments using Paramecium aurelia, Paramecium caudatum, and Paramecium bursaria were conducted by Gause . When each Paramecium species was grown alone, they showed___________________________ growth to an ______________________________population size (________________________________________ ). When P. aurelia and P. caudatum were grown together, ________caudtum___________went extinct and _________P.aurelia___________ went to______________________ . This pattern of competition outcome is called _________competitive exclusion________________________ . P. aureliaP. caudatumP. bursaria200100NDays1020Each species grown alone10 20P. aureliaP. caudatum200100NDays1020P. aurelia and P. caudatum together10 20When P. aurelia and P. bursaria were grown together, both went to_____________________________ , but the population sizes were___________________________ than when grown alone. This pattern of competition outcome is called________competitive coexistance____________________________ . Limiting similarity: competitors are more likely to ____________________if they _____________________in one or more of their ecological requirements or preferences. Competitive exclusion or coexistence can vary with____________________ (abiotic and biotic) conditions. Potentially limiting resources include: 1. 2. 3. 4. 5. 6. Lotka-Volterra Competition Model Start with logistic growth for a single species: r: pre capita growth rate of population N: K: maximum (equilibrium) population size N: We create two equations, one for each species, and add a term to keep track of the other species. But, that doesn’t account for the EFFECT of each species on the other. Competition coefficients quantify the effect of _____________________________on the other.α12: the effect ____one additional individual______of species 2 on the resources used by species 1, measured in “species 1 equivalents” α21: the effect one additional individual of_____Species 1_______ on the resources used by species 2, measured in “species __2 equivalents_________ ” Full Lotka-Volterra Competition Model: Solving for equilibrium: set ______dN/dt =0___________ and solve. So then we can re-arrange to solve for equilibrium: Plotting Competitive Interactions Species 1 zero growth isocline plots the line: (notice what your axes labels are…)Species 2 zero growth isocline plots the line: Population Size of Sp2 Outcome expected (predicted) in this example: _________coexistence____________of both species. Four Possible Outcomes of CompetitionLabel each phase plane with the competitive outcome and stable/unstable equilibrium. In Gause’s L-V model for two competing species the zer-population-growth isocline for species 1 specifies C. the combinations of population density for the two species that allow competitive coexistence More Complex Competition A _______resource_______________is something that is used or consumed by an organism to grow or maintain itself. A ____________limiting resource___________________ is something that, as it is used or consumed by an organism, becomes _______less available_____________and thus slows the growth of that individual and/or other individuals present. If two species actively consume the same ______limited resource_________________, making it less available to one or the other, then interspecific competition occurs. The result of interspecific competition in this interaction is: Who is the winner of the competition?Competitive coexistence can be reached if 2 species are competing for ________________________________. This suggests in _______________________________ competitive abilities for different resources. What is Liebig’s Law of the Minimum? Leibig’s Law of the Minimum says that population will grow until ___________________________________. Usually, there is competition for _______________________________limiting resources and the availability of these resources can be ________________________ which will affect species performance or _____________. List some different examples of limiting resources for plants and animals: Niche Concept Habitat: ______________an organism lives Niche:____ -dimensional hypervolume of ____________________conditions in which a population has positive_______________________________ . Competitive exclusion hypothesis: no two species can share__________________________________ . Fundamental niche: the ______________________conditions in which a species can ______________and _____________in the ___________________________of biotic interactions. Realized niche: the conditions in which a species ________________________lives and reproduces in the _______________________of biotic interactions. Niche overlap: the areas of two species’ niches that ________________________________.If two species are competing for the same resources, the better competitor will ___________________the niche of the poorer competitor. Niche breadth: the __________________ of one__________________ used by a __________________ species. Climatic niches often determine____________________________________ . Field Studies: Competition and the Niche Connell Barnacle Study: a __________________ experiment to understand __________________ . __________________ limits the lower tidal distribution of Balanus, whereas __________________ limits it’s upper tidal distribution. __________________ limits the lower tidal distribution of Chthamalus, whereas__________________ limits it’s upper tidal distribution. Cattail study: in the__________________ of competition, both Typha species grow in areas with similar