1 | Page
ECOL111: Species Interactions Questions
and Correct Answers
Interspecific competition Ans: process by which individuals of
one species suffer reductions in fecundity, survivorship or growth
as a result of the presence of actives of a second species
Exploitation competition Ans: indirect competition through shared
resources, e.g. one species over exploring a resource effecting the
resources availability for other species relying on it.
Interference competition Ans: direct competition involving one
species actively preventing access to resources, or inhibiting
growth/survival of another species.
Functional responses to interspecific competition Ans: when
competition is introduced its expected that there will be a change
in one or both species behavior, in efforts to lessen the effects of
competition.
Numerical responses to interspecific competition Ans: competitors
are expected to have a population increase over time (until
carrying capacity is reached), further evidence of competition from
the introduction of both species is there should be a lower
equilibrium density with multiple species.
Lotka-Volterra equation Ans: calculates the rates of growth for two
competing species
Competitive exclusion Ans: Occurs when a superior competitor
causes the extinction of a weaker competitor, although this is rare
because competitive advantage depends on conditions,
environment stability, and niche adjustments.
© 2025 All rights reserved
, 2 | Page
Competitive non-exclusion Ans: Often occurs when the
environment is regularly disturbed resulting in area not being
colonized by superior competitors, therefore there is a gap for
weaker competitor to temporarily occupy.
Mechanisms that favor Coexistence Ans: environmental
heterogeneity, aggregated distributions, resource partitioning.
Competition effect on Evolution Ans: As competition reduces an
competitors fitness evolution will favor organisms that largely
avoid these effects, therefore organisms with niche that avoid
competition become dominant in a species.
Character Displacement Ans: characteristics and traits in an
organisms evolves to lessen the effects of competition as a result
of extreme competition, e.g. tropical birds beaks are hugely
variable because they evolved different diets, in order to reduce
competition for a resource.
Predation Ans: relationship between a predator and prey, where
one organism benefits and the other is harm (killed).
Predators Ans: organisms that rely on other organisms for
nutrients and energy, typically kill their victim.
Grazers Ans: organisms that rely on vegetation for nutrients and
energy, typically do not kill their victim (don't eat whole plant).
Parasites Ans: an organisms that relies on another species (host)
for survival.
Parasitoids Ans: an organisms that has young that develop within
another organism, typically smaller then host.
© 2025 All rights reserved
ECOL111: Species Interactions Questions
and Correct Answers
Interspecific competition Ans: process by which individuals of
one species suffer reductions in fecundity, survivorship or growth
as a result of the presence of actives of a second species
Exploitation competition Ans: indirect competition through shared
resources, e.g. one species over exploring a resource effecting the
resources availability for other species relying on it.
Interference competition Ans: direct competition involving one
species actively preventing access to resources, or inhibiting
growth/survival of another species.
Functional responses to interspecific competition Ans: when
competition is introduced its expected that there will be a change
in one or both species behavior, in efforts to lessen the effects of
competition.
Numerical responses to interspecific competition Ans: competitors
are expected to have a population increase over time (until
carrying capacity is reached), further evidence of competition from
the introduction of both species is there should be a lower
equilibrium density with multiple species.
Lotka-Volterra equation Ans: calculates the rates of growth for two
competing species
Competitive exclusion Ans: Occurs when a superior competitor
causes the extinction of a weaker competitor, although this is rare
because competitive advantage depends on conditions,
environment stability, and niche adjustments.
© 2025 All rights reserved
, 2 | Page
Competitive non-exclusion Ans: Often occurs when the
environment is regularly disturbed resulting in area not being
colonized by superior competitors, therefore there is a gap for
weaker competitor to temporarily occupy.
Mechanisms that favor Coexistence Ans: environmental
heterogeneity, aggregated distributions, resource partitioning.
Competition effect on Evolution Ans: As competition reduces an
competitors fitness evolution will favor organisms that largely
avoid these effects, therefore organisms with niche that avoid
competition become dominant in a species.
Character Displacement Ans: characteristics and traits in an
organisms evolves to lessen the effects of competition as a result
of extreme competition, e.g. tropical birds beaks are hugely
variable because they evolved different diets, in order to reduce
competition for a resource.
Predation Ans: relationship between a predator and prey, where
one organism benefits and the other is harm (killed).
Predators Ans: organisms that rely on other organisms for
nutrients and energy, typically kill their victim.
Grazers Ans: organisms that rely on vegetation for nutrients and
energy, typically do not kill their victim (don't eat whole plant).
Parasites Ans: an organisms that relies on another species (host)
for survival.
Parasitoids Ans: an organisms that has young that develop within
another organism, typically smaller then host.
© 2025 All rights reserved
