chapter 13 Flashcards
has been regarded as the major force behind species divergence and specialization
competition
A relationship that affects the populations of two or more species adversely
interspecific competition
six types of interactions for most instances of interspecific
competition
(1) consumption, (2) preemption, (3) overgrowth,
(4) chemical interaction, (5) territorial, and (6) encounter
occurs when individuals of one species inhibit individuals of another by consuming a
shared resource, such as the competition among various animal
species for acorns
Consumption competition
occurs primarily
among sessile organisms, such as barnacles, in which the occupation by one individual precludes establishment (occupation)
by others
Preemptive competition
occurs when one organism literally grows over another (with or without physical
contact), inhibiting access to some essential resource
Overgrowth competition
chemical growth inhibitors or toxins released by an individual inhibit or
kill other species
chemical interactions
in plants, in which chemicals produced by some plants inhibit germination and establishment of other species
Allelopathy
results from the behavioral exclusion of others from a specific space that is defended as a territory
Territorial competition
results when nonterritorial meetings between individuals negatively affect one or both of the participant species
Encounter competition
states that “complete competitors” cannot coexist
competitive exclusion principle
two species (non-interbreeding populations) that live in the same place and have exactly the same ecological
requirements
complete competitors
Under this set of conditions, if population A increases the least bit faster than population B, then A will eventually outcompete B, leading to its local extinction
competitive exclusion principle
competitive exclusion principle assumptions
- exactly the same resource requirements
- environmental conditions remain constant
What ecological conditions are necessary for coexistence of species
that share a common resource base?
environmental factors
spatial and temporal variations in resource availability
competition for multiple limiting resources
resource partitioning
the range of physical and chemical conditions under which it
can persist (survive and reproduce) and the array of essential
resources it uses
ecological niche
the ecological niche in the absence of interactions with other species
fundamental niche
he portion of the fundamental niche that a species actually exploits as a result of interactions with other species
realized niche
when a species’ niche expands in response to the removal of a competitor
competitive
release
occur when a species invades an island that is free of potential competitors, moves
into habitats it never occupied on a mainland, and becomes more abundant
competitive
release
suggests
that if two species have identical resource requirements, then
one species will eventually displace the other
competitive exclusion principle
differences in the range of resources used or environmental tolerances
“niche differentiation”
a direct result of differences among co-occurring species
in specific physiological, morphological, or behavioral adaptations that allow individuals access to essential resources while at the same time function to reduce competition
resource partitioning
hypothesis of resource portioning as a product of coevolution between competing species
ghosts of competition
past
When the shift
involves features of the species’ morphology, behavior, or
physiology
character displacement
complex interaction that seldom involves the interaction between two species for a single limiting resource
competition
describe four possible outcomes of interspecific competition
Lotka–Volterra
four possible outcomes
of interspecific competition of the Lotka-Volterra model
Species 1 may outcompete species 2; species 2 may outcompete species 1; One is unstable equilibrium, in which the
species that was most abundant at the outset usually outcompetes the other. A final possible outcome is stable equilibrium, in which two species coexist but at a lower population level than if each existed without the other.
