b50 midterm 2 Flashcards
a non-trophic interaction between individuals, in which each is negatively affected by their shared use of a resource that limits their growth, survival, and/or reproduction
competition
competition between individuals of the same species
intraspecific competition
competition between members of different species
interspecific competition
occurs when one species directly interferes with its competitor’s ability to access a limited resource
interference competition
occurs when one species reduces the availability of a limiting resource to another species, simply by using it (indirect competition)
exploitation competition/resource competition
the study of ecological interactions between individuals of two or more species
Community ecology
interactions among multiple species
community ecology
what are the two types of interspecific competition
resource/exploitative and interference competition
competition between two species for a shared resource; by consuming or exploiting that resource, individuals of each species make it less available for individuals of other species
resource/exploitative competition
the full range of conditions (biotic and abiotic) and resources within which individuals of a species can survive and reproduce
fundamental niche
in the context of interspecific competition, the niche space that individuals of a species can access in the presence of their competitors
realized niche
an alteration in the way individuals of a species use resources in the presence of a competitor species
niche shift
the splitting of limited resources among individuals of two competing species
resource partitioning
the situation where no more individuals of a population or species are present in a location or on Earth; a possible long-term outcome of competition or predation
Extinction
the idea that past competition between two or more species may have altered resource use and interaction sufficiently that the species no longer compete; the only lingering signs of their previous competition are non-overlapping but similar resource use
Ghost of competition past
the restriction or removal of individuals of one species from a location by another species; a possible long-term outcome of competition or predation
Exclusion
a change in gene frequency in a population in which two coevolved species respond to each other’s adaptations over time
Evolution
the coexistence of individuals of two species in the same spatial location
sympatry
the spatially disjunct existence of two or more groups- that is, the existence of groups in separate and unconnected locations
allopatry
interspecific competition requires what
a limited resource
the study of multispecies interactions
community ecology
where are there more predator-prey relationships?
in the arctic because there is less biodiversity
a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically. species
keystone species
most food chains are how many trophics high
4-5 (textbook says 6 but prof says its rare)
compared to lower trophic level organisms, top predators occur at higher densities or lower densities?
lower densities due to limits in energy transfer efficiency
where can we find humans on the food chain?
at the top
produced from within a system
endogenous
produced from outside a system
exogenous
Control of the energy flow in a food web by organisms at the basic tropic level (autotrophs). The abundance of autotrophs limits the amount of energy that is available to, and thus, the abundance of, species at higher trophic levels.
Bottom up control
Control of the energy flow in a food web by organisms at the upper trophic levels. By eating organisms at the lower trophic levels, the species at the upper trophic levels control the biomass and abundance of lower levels.
top down control
few primary producers, low biomass
oligotrophic
many primary producers, high biomass
eutrophic
adding phosphorous into the water, leads to algae production, why is this bad?
because algae deplete the water of oxygen, and fish die
what was the example of bottom up control used in lec 9
algae production in water, killing the fish because fertilizers use phosphorous and increase algae production but too much algae depletes the water of oxygen, so it is bottom up in the way that the lower levels (trophic level 1= algae) are affecting and limiting upper levels (ex. fish)
why do we need top predators such as wolves in an ecosystem?
because they keep herbivores and lower level consumers in check (brown world without wolves and green world with wolves)
food chains with odd numbers of trophic levels have _____ densities of primary producers
high (a green world)
food chains with even numbers of trophic levels have _____ densities of primary producers
low (a brown world)
something that feeds on dead organic material
detritivore
how can you determine a species diet
direct observation, gut content, and fecal analyses
variants of chemical elements that have differing numbers of neutrons in the atomic nucleus that do not decay radioactively over time
stable isotopes
ecologists use what to measure the ratio of different isotopes in tissue samples
mass spectrometer
species that have a disproportionally large effect on community structure, function, and/or diversity, relative to their own biomass and/or abundance
keystone species, occur in small numbers but have a large effect
species with a large effect on community structure, function, and/or diversity that is proportional to its biomass and/or abundance
foundation species, occur in large numbers and have a large effect
what is an example of a keystone species
mosquitos, you kill mosquitos, you kill a lot of other things as swell
bees, butterflies, a brick lol
species that create, modify, maintain, or destroy physical habitat
ecosystem engineer
both keystone and foundation species can be
ecosystem engineers
the overall effect of one species on a second species when both species interact with a third species or with a shared resource; the third species or shared resource mediates the interaction in such a way that the effect may even change in sign or direction.
indirect effect
an interaction between species in which the individuals of one species eat the individuals of the other.
trophic interaction
a feeding or eating level within a food chain or food web
trophic level
the direction in which nutrients and resources are moving up or down a food chain.
energy flow
a hierarchical linear set of interacting species depicting tropic interactions.
food chain
a representation of the flow of trophic energy up a food chain.
tropic pyramid
what are the different types of exploitative/consumer resource interactions
predation, herbivory, and paratism
covert the energy of sunlight (photosynthesis) or inorganic compounds (chemosynthesis) into chemical energy stored in the carbon-carbon bonds of organic compounds
autotrophs
obtain energy by consuming organic compounds from other organisms
heterotrophs
an interaction in which individuals of one species increase in fitness by consuming individuals (or parts of individuals) of another species, who experience a decrease in fitness
exploitation
what is an example of a non-exploitative interaction
detritivory (detritivores break down and consume non-living organic material)
roughly how many species on Earth are parasitic
50%
prevent being found by the consumer
primary defenses
deter consumers from attacking
secondary defenses
escape or fight back when attacked
tertiary defenses
what does alpha describe
alpha is the competition coefficient describing the effect of species 2 on species 1 on a per capita basis
an individual of species 2 affects the per capita population growth rate of species 1 by the SAME amount as an individual of species 1 would (the effects of interspecific and intraspecific competition are equal)
alpha = 1
an individual of species 2 decreases the per capita population growth of species 1 by a smaller amount than one individual of species 1 would
alpha < 1
an individual of species 2 decreases the per capita growth rate of species 1 by a larger amount than one individual of species 1 would
alpha > 1
what aims to describe the population growth of two competing species over time
Lotka-Volterra competition model
parasites that live inside
endoparasites
parasites that live outside their hosts
ectoparasites
a complex cycle between predator (exploiter) and prey in which the density or abundance of each species alters the density or abundance of the other species; predator density increases as prey density increases, but prey density decreases as predator density increases
exploiter prey cycle
a term in the Lotka-Volterra predator-prey model that represents the combination of the capture success and eating mode of an organism
Capture rate (f)
a population’s maximum per capita growth rate in a particular habitat
intrinsic rate of increase
a term in the Lotka-Volterra predator-prey model that translates consumed prey into an expected number of offspring for a focal species
Exploiter conversion factor (c):
lines of zero growth
isoclines
what are the long term outcomes of competition
extinction, exclusion, and evolution
if isoclines do not cross what occurs
competitive exclusion
when isoclines cross what occurs
competitive exclusion (one species eventually wins) or coexistence (with both species below their carrying capacity)
what did Gause study
competitive exclusion (two species competing for the same limited resources cannot coexist at constant population values; one species will typically outcompete and exclude the other)
- he studied Paramecium
species using a limiting resource in different ways
resource partitioning
past competition may explain many current ecological patterns, but in most cases, we will never know
Ghost of competition past
an adaptive shift in the population-level of a trait that is critical to resource acquisition and other competitive interactions
character development (ex. different beak sizes leads to different uses, eat different seeds)
what did Robert MacArthur study
resource partitioning in birds (different birds, use, live on, feed on different areas of trees) coexistence!
what is r
per capita growth rate
what is an example of a non-exploitative interaction
detritivory (detritivores break down and consume non-living organic matter)
are carnivores generalists or specialists?
generalists meaning that they have broad diets
are herbivores generalists or specialists?
specialists meaning that they feed on a relatively narrow range of plant species (or even parts of plant species)
are parasites generalists or specialists?
specialists
the stakes are higher for the resource species in a consumer-resource encounter: it might lose its life, while the consumer might just lose out on a meal if unsuccessful
life-lunch principle
describes the number of prey eaten per predator per unit time as a function of prey density, may stabilize or destabilize predator prey dynamics
functional responses (type I, II, III)
type WHAT functional response assumes that the number of prey eaten increases linearly with density, with no upper limit
type I
type WHAT functional response considers handling time and leads to destabilizing dynamics
II
type WHAT functional response considers prey refuges and prey switching by the predator at low densities and leads to stabilizing dynamics
type III
organisms that live in or on other organisms
symbionts
symbionts can be what 2 things
mutualists or parasites (majority are parasites)
consumes the tissues or body fluids of the organism on which it lives (the host)
parasite
parasites that cause disease
pathogens
parasites that can be seen with the naked eye or through a basic microscope
macroparasites
parasites that are too small to be seen with the naked eye
microparasites
parasites that live on the outer body surface of the host
ecoparasites
parasites that live inside their hosts, within cells, tissues, or the alimentary canal
endoparasites
parasitic worms are also called
helminths
what are the conditions for the Basic reproductive ratio (R0) for a disease to die out
R0 < 1
what are the conditions for the Basic reproductive ratio (R0) for a disease to spread
R0 >1
what SIR model has no recovery; appropriate for diseases that are (almost) always fatal
SI-model
what SIR model: infection does not guarantee immunity after recovery
SIS model
what SIR model: accounts for delays between infection and become infectious
SEIR model (e stands for exposed, but cannot transmit disease yet because incubation period has not passed)
what SIR mode: inclusion of chronic carriers that transmit at low rates for a long time
SICR model
what signs represent the shorthand for competition
(-,-)
what signs represent the shorthand for exploitation
(+,-)
an exploiter species that causes disease in its hosts
pathogens
a niche element that can be used up
resource
is detritivory exploitation or predation?
no
what are the four possible outcomes of exploitation
- prey extinction that leads to exploiter extinction
- exploiter extinction with surviving prey
- exploiter-prey cycles
- stable coexistence
the speed of a chemical reaction is dependent on the concentrations of the chemicals, because a higher concentration means the chemical elements are more likely to randomly bump into each other
mass action or the law of mass action (offers a good first estimate of exploiter-prey encounter rates, it seems reasonable that organisms bump into each other based on their density in a habitat)
population dynamics that cycle with decreasing amplitude through time
damped oscillations
the number of prey eaten per exploiter per unit of time
functional response
a pattern, observed in some species, in which there is a fitness decline as density declines
allee effect
combination of factors that leads to new individuals entering the next age class, used most frequently to refer to plants entering a new reproductive class
recruitment
an insect exploiter species that attacks other insects (hosts) and lays its eggs or larvae inside the host. These eggs or larvae will eventually develop, consume, and kill the host insect in the process.
parasitoids
- like predators, they kill their prey or hosts
- like parasites they tend to have just one prey or host in their lifetime
an organism that supports the adult form of a parasite
definitive host
an organism that supports the non-adult form of a parasite
intermediate host
the ability of an organism to conceal itself
crypsis
a colouration pattern found in prey organisms that signals danger (ex. poison) to a potential predator
aposematic coloration
mimicry is an example of what type of defense
secondary defense
a form of mimicry in which there is a selective advantage for both the mimic and the model to closely resemble each other, thereby gaining protection by reinforcing a cue sent by their similar trait
mullerian mimicry - reinforces a message
a form of interspecies mimicry in which the mimic sends a false signal to interacting species. ______ mimicry is common in prey species that do not actually have a mechanism to kill or harm the predator (ex. poison) but show the same signal or pattern as a species that does
Batesian mimicry - dilutes a message
playing dead-tertiary defense
thanatosis
a state of coexistence among prey species in a food web that is facilitated, indirectly, by a keystone or other predator that selectively consumes large numbers of a competitively dominant prey species, thus allowing other species to survive and increase the diversity of the community
predator-mediated coexistence
