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13 Cards in this Set

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  • Back
what is interspecific competition?
interspecific competition involves two or more species, individuals seek a common resource in short supply
What to forms are there of interspecific competition?
exploitation & interference
What are the 6 types of interactions to account for most instances of interspecific competition?
1) consumption: occurs when individuals of one species inhibit individuals of another by consuming a shared resource (acorns example)

2) Preemptive: occurs primarily among sessile organisms, such as barnacles, where the occupation by one individual precludes establishment by occurs.

3) overgrowth competition occurs when one organism literally grows other another (with or without physical contact) inhibiting access to some essential resource.

4) Chemical interactions : chemical growth inhibitors or toxins released by an individual inhibit or kill other species

5) territorial competition results from the behavioral exclusion of others from a specific space that is defended as a territory

6) encounter competition results when non territorial meeting between individuals negatively affect one or both of the participant species.
Define exploitation and interference. how do they differ from each other?
exploitative competing individuals do not directly interact with one another. instead individuals respond to the level of resource availability that is depressed by the presence and consumption of other individuals in the population.

interference: individuals interact directly with each other, preventing others from occupying a habitat or accessing resources with in .
what is the logistic equation for population growth?
America Alfred Lotka and Italian Vittora Volterra independently arrived at mathematical expressions to decribe the relationship between two species using the same resource. they both began with the logistic equation for population growth. How did they modify the logistic equation?
by adding to it a term to account for the competitive effect of one species on the population growth of the other.

For species 1, this term is alpha N2, where N2 is the population size of species 2, and alpha is the competition coefficient that quantifies the per capita effect of species 2 on species 1. Similarly, for species 2, the term is beta N1, where beta is the per capita competition coefficient that quantifies the per capita effect of species 1 on species 2.
what are the pair of equations that consider both intraspecific and interspecific competition.
species 1: dN1/dt=r1N1*[(K1-N1-alphaN2)/K1]

species 2: dN2/dt=r2N2[(K2-N2-betaN1)/K2]
what happens if alpha or N2 =0 for Lotka-Volterra equations
the population of each species grows logistically to equillibrium at K, the carrying capacity
what are the four possible outcomes of interspecific competition? ( when the two isoclines are combined)
1. as species 1 continues to increase, species 2 eventually becomes extinct.

2. the situation is reversed species 2 wins, leading to the exclusion of species 1

3. which species wins the competition depends on the initial populations of the two species

4.the result of competition differs in that neither species can exclude the other and the result is coexistence
in ___ of the four situations by the lotka volterra equations one species drives the other to extinction.
what is the "competitive exclusion principle"
which states that "complete competitors" cannot coexist.

Complete competitors are two species (non interbreeding populations) that live in the same place and have exactly the same ecological requirements. Under this set of conditions, if population A increases the least bit faster than population B then A will eventually outcompete B, eventually leading to its local extinction.
Competitive exclusion principle invokes compepition for a limited resource, what else does it involve? what are the assumptions of the principle?
the competitive exclusion principle involves assumptions about the species involved as well as the environment in which they exist.

1) this principle assumes that the competitors have exactly the same resource requirement.

2) it assumes that enironmental conditions remain constant. such conditions rarely exist
Competition is influenced by non resource factors, explain
enironment factors that directly influence a species survival, growth, and reproduction but are not consumable resources( such as temperature or pH)