Final Exam: Fall 23 Flashcards
Competition for a single resource
population dynamics of two competing species can be modeled by extending the logistic growth equation to multiple species
What is N1
the number of species 1
what is N2
the number of species 2
What is intraspecific
1/K or 1/K2
What is interspecific
lil fish thing/K1 or B/K2
Species Richness
often increases from the local to landscape scale because habitat diversity increases along this dimension
alpha (local) diversity
average number of species in a relatively small area of homogenous habitat
gamma (regional) diversity
number of species in all of the habitats that comprise a large geographical region
beta (turnover) diversity
number of species that differ in occurrence between regional and local habitats
regional species pool
collection of species that occurs within a geographical region
How to calculate gamma diversity
Add all of the numbers from the sites and the shared areas
how to calculate alpha diversity
add all from just the main sites (no shared areas) and then divide by the number of main sites
how to calculate beta diversity
gamma diversity - alpha diversity
intraspecific competition
competition among individuals of the same species
interspecific competition
competition among individuals of a different species
what is a resource
anything an organism consumes or uses that causes an increase in population growth rate when it becomes more available.
more resources means more population growth
renewable resources
resources that are regenerated at some rate
nonrenewable resources
resources that are not regenerated at an appreciable rate
liebigs law of the minimum
population sizes are limited by the most limiting resource
what are diatoms
silica for cell walls
suppose you have found that fertilizing grain fields with nitrogen increases crop yield
based on liebigs law of the minimum, how is crop yield most likely to respond as you add more and more nitrogen?
A. yield grows at a faster and faster rate
B. yield grows at a constant rate
C. yield grows but growth slows and eventually stops
C. yield grows but growth slows and eventually stops
competitive exclusion principle
two species cannot coexist indefinitely when they are both limited by the same resource. extinction of population
competition among related species
darwin suggested competition is most intense between related species because they have similar traits and consume similar resources
competition among distant species
competition can also be intense among distantly related species that consume a common resource
given the tremendous diversity in tropical forests and the principle of competitive exclusion, what might explain why so many species coexist there?
A. each species inhabits its own niche and therefore doesn’t share limiting resources
B. Each species depends on the density of at least one other species (mutualism)
C. Competition may not actually drive species to extinction
D. Any of the above
D. Any of the above
abiotic conditions
the ability to compete well may be countered by the ability to persist in harsh abiotic conditions
exploitative competition
competition in which individuals consume and drive down the abundance of a resource so that other individuals survive and reproduce more poorly
interference competition
competitors directly defend resources
apparent competition
two species have a negative effect on each other through an enemy, such as a predator, parasite ,or herbivore
allelopathy
a type of interference competition that occurs when organisms use chemicals to harm their competitors
apex predators eats mesopredators and herbivores, and mesopredators only eat herbivores.
herbivores and meso predators are
1. prey and predator
2. competitors
3. mutualists
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 1, 2, and 3
A. 1 and 2
What is mutualism
mutualism is a positive interaction between two species in which one species receives benefits that only the other species can provide
what is a generalist
species that interact with many other species
what is a specialist
species that interacts with one or a few closely related species
what is an obligate mutualists
species that require each other to persist
what is a facultative mutualist
species where the interaction is not critical to the persistence of either species
what are lichens
fungus + algae/cyanobacteria
mycorrhizal fungi
fungi surround plant roots and help plants get water and minerals
endomycorrhizal fungi
hyphal penetrate root cells between cell walls and the cell membrane
ectomycorrhizal fungi
hyphae surround plant roots and enter between root cells but rarely into the cells
arbuscular mycorrhizal fungi
endomycorrhizal fungi that infect many plants including apple trees, peach trees, coffee trees, and grasses. includes 70-90% of land plant species
mutualistic interactions between plants and bacteria
help plants convert unusable forms of minerals into forms that they can use
suppose that some humans decide to eat all the honeycomb, wax, grubs, etc leaving nothing for the honeyguide. ecologically, the humans and honeyguides are
A. mutualists and mutualists
B. predators and prey
C. parasites and hosts
D. assholes and unlucky
C. parasites and hosts
suppose that apex predators only eat mesopredators and mesopredators only eat herbivores
apex predators and herbivores are
A. prey and predator
B. competitors
C. mutualists
D. none of the above
C. mutualists
negative interactions
when a species in a mutualism provides a benefit to another species, but no longer receives a benefit in return
what is cheating
occurs when one species receives a benefit but does not provide one in return
a cheating mycorrhizal fungus is most unlike
A. a civet that digests coffee beans instead of pooping them out
B. a cancer cell that ignores signals to stop dividing
C. a honey bee that eats nectar but doesn’t transfer pollen
B. a cancer cell that ignores signals to stop dividing
effects on species distributions
the disruption of a mutualism may cause a decline of the species involved and a reduction in their distribution and abundance
communities and mutualism
mutualism can also change the abundance of species through a chain of interactions
the effcts of mutualism on ecosystem function
mutualisms can also have effects at the level of the ecosystem. more nutrients and more productivity
mutualism and convervation
loss of disperses can result in a reduction in plant abundance
zonation meaning
distribution of species into different zones. there are unique or different communities at each zone
ecotone
boundary created by sharp changes in environmentally conditions over a relatively short distance, accompanied by a major change in the composition.
`interdependent communities
communities in which species abundances are positively linked
independent communities
communities in which species abundances are not positively linked
interdependence
removing a species should cause other species to decline in abundance
independence
removing a species should cause negligible or positive changes in abundance of other species
assuming a model of species independence, which ecological relationships are not possible
1. competition
2. predation
3. mutualism
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 1, 2, and 3
C. 2 and 3
species richness meaning
number of species in a community
relative abundance
proportion of individuals in a community represented by each species
rank-abundance curves
curve that plots relative abundance of each species in rank order from most abundant to least abundant
species evenness
measure the different in relative abundance of species
effect of resources on diversity
experiments that manipulate productivity by adding nutrients to an ecosystem commonly cause a decline in the species richness of producers.
effect of habitat diversity
communities with a higher diversity of habitats should offer more potential niches and a higher diversity of species
keystone species
species whose presence substantially affects the abundance of other species in the community
ecosystem engineers
keystones species that affect communities by influencing the structure of a habitat
intermediate disturbance hypothesis
low disturbance: slow growth, competitive, dominant
high disturbance: specialist on disturbance dominant
food chain
a series of organisms each dependent on the next as a source of food
food web
consists of all the food chains in a single ecosystem
what is a guild
within a level, species that feeds on similar items
direct effect meaning
interaction between two species that does not involve other species
indirect effect meaning
interaction between two species that involves one or more intermediate species
trophic cascade meaning
indirect effects in a community by:
a predator (top-down cascade_
a producer (bottom-up cascade)
density-mediated indirect effect
indirect effect caused by changes in density of an intermediate species
trait-mediated indirect effect
indirect effect caused by changes in traits of an intermediate species
bottom-up control
abundances of trophic groups determined by the amount of energy available from producers
top-down control
abundances of trophic groups determined by the existence of predators at the top of the food web
succession meanin
species composition of a community changes over time
pioneer species meaning
earliest species to arrive at a site
climax community (metastable)
“final” seral stage in succession
observing succession
direct observation of changes over time is the clearest way to record succession in a community
chronosequence meaning
a sequence of communities that exist over time at a given location
primary succession
the development of communities in habitats that are initially devoid of plants and organic soil, such as dunes, lava flow, and bare rock
secondary succession
development of communities in disturbed habitats that contain no plants but still contain organic soil
glacier retreat often leads to ______ succession and wildfire lead to _____ succession
A. primary; primary
B. primary; secondary
C. secondary; primary
D. secondary; secondary
B. primary; secondary
terrestrial succession meaning
sequence of seral stages before a climax community can differ depending on variation in historic abiotic conditions, soil, fertility, and disturbances
animal succession meaning
changes in the plant community change the habitats available to animals, which causes changes in the animal community
succession in intertidal communities meaning
can occur rapidly after a disturbance due to the short generation time of dominant species
stream succession meaning
streams undergo rapid succession because organisms can move downstream from sites less disturbed to sites and recently disturbed
lake succession meaning
helps us to understand timescale of ecosystem change that effects carbon stage
the changes in species diversity
during succession, species richness increases rapidly at first, followed by a plateau and a small decline
facilitation meaning
one species increases the probability that a second species can become established
inhibition meaning
one species decreases the probability that a second species will become established
tolerance meaning
species do not alter the environment in ways that either facilitate or inhibit other species
priority effect meaning
when the arrival of species at a site affects the colonization of other species
you can determine which mechanisms drive succession by adding or removing a species. suppose that you add a grass species and a tree species.
under facilitation, subtracting grass _____ the chance tress establish. under inhibition, subtracting grass ____ the chance trees establish.
A. decreases; decreases
B. decreases; increases
C. increases; decreases
D. increases; increases
B. decreases; increases
what is a transient community
a climax community that is not persistent
gaps in a climax community
small-scale disturbances in an area with a climax community can allow growth of species that are not considered climax species
fire-maintained climax community
successional stage that persists as the final seral stage due to periodic fires
grazer-maintained climax community
successional stage that persists as the final seral stage due to intense grazing
gross primary productivity (gpp)
rate of solar or chemical energy capture and assimilation by producers into chemical bonds in an area
net primary productivity (npp)
rate of energy assimilation by producers and conversion into producer biomass in an area
measuring primary productivity, in aquatic systems
measuring CO2 does not provide a good estimate of NPP because CO2 is rapidly converted into bicarbonate ions. O2 change measured instead
Remote sensing
how productivity across large spatial scales is measured
suppose that youre measuring the gross primary product of an aquatic plant. when transferring the plant to your light-dark chamber, you have accidentally moved some plankton along with the plant.
You perform the day/night measurements to determine NPP and respiration rate of the plant . which kind of plankton in the chamber will most skew your calculation of GPP?
A. zooplankton
B. phytoplankton
C. both
D. neither
B. phytoplankton
egested energy
consumed energy that is excreted or regurgitated
assimilated energy
energy consumers digest and absorb
respired energy
assimilated energy a consumer uses for respiration
net secondary productivity
rate of consumer biomass accumulation in a given area
productivity in terrestrial ecosystems
nutrients- particularly nitrogen and phosphorus- can strongly affect NPP in terrestrial ecosystems
aquatic ecosystems are limited by ______ in addition to temperature, precipitation, and nutrients
light
what can limit NPP of aquatic ecosystems
nitrogen and phosphorus
what elements limit productivity in the ocean
silicon and iron
trophic pyramid meaning
a chart composed of stacked rectangles representing the rate of energy transfer amount of biomass in each trophic group
consumption efficiency meaning
the percentage of energy or biomass in a trophic level is consumed by the next higher trophic level
assimilation efficiency
the percentage of consumed energy that is assimilated
net production efficiency
the percentage of assimilated energy that is used for growth and reproduction; the percentage of assimilated energy that remains after respiration
ecological efficiency (food chain efficiency)
the percentage of ent production from one trophic level compared to the next lower trophic level
do aquatic ecosystems or terrestrial ecosystems have more trophic levels?
aquatic ecosystems because of differences in the ecological efficiencies
aquatic (often five)
terrestrial (three to four)
energy residence time
the length of time that energy spends in a given trophic level
biomass residence time
the length of time that biomass spends in a given trophic level
how else can energy and biomass times be used
can be calculated for dead organic matter consumed by scavengers, detritivores, and decomposers.
ecological stoichiometry
the study of the balance of nutrients in ecological interactions, such as between an herbivore and a plant
landscape ecology meaning
the field that considers the spatial arrangement of habitats at different scales and examines how they influence individuals, populations, communities, and ecosystems
legacy effects meaning
long-lasting influence of historical processes on the current ecology of an area
effects of fragment size
more fragments = decreased fragment size = lower species richness
equilibrium theory of island biogeography
number of species on an island reflects a balance between the colonization of new species and the extinction of existing species. rate of colonization balanced by rule of extinction
where is total species richness the highest and lowest?
highest near the tropics and declines toward the poles
oceans have ______ species richness at lower latitudes
increased
at any given latitude, there are _____ species where there is greater ecological heterogeneity
more
energy diversity hypothesis
sites with higher amounts of energy are able to support more species and higher abundances of individual species
potential evapotranspiration (PET)
amount of water that could be evaporated from the soil and transpired by plants given the average temperature and humidity
continental drift
movement of landmasses across earths surface
pangaea
single landmass that existed on earth about 250 mya
laurasia
northern landmass that separated from pangaea about 150 mya
gondwana
southern landmass that separated from pangaea
instrumental value of biodiversity
the economic value a species can provide
intrinsic value of biodiversity
the inherent value of a species, not tied to any economic benefit
ecosystem services
ecological characteristics, functions, or processes that directly or indirectly contribute to human wellbeing
provisioning services
ecosystem services that produce food, timber, fibre, etc
regulating services
flood control, storm protection, water regulation, human disease regulation, water purification, air quality maintenance, pollination, pest control, and climate control
cultural services
recreating, aesthetic, scientific, cultural identity, sense of place, or other ‘cultural’ beliefs
supporting services
basic ecosystem processes such as soil fermentation, primary productivity, nutrient cycling and the existence of habitat
mass extinction
significant increase in extinction rate relative to speciation rate.
climate change, volcanism, asteroid impacts are to blame
how have humans impacted extinction
rapidly accelerated extinction rates since the industrial revolution. potential “sixth” mass extinction
International union for conservation of nature categories to describe extinction risk:
extinct
extinct in the wild
threatened
what happens if there is a decline in genetic diversity
it reduces the probability that a population is able to survive changing conditions
what is the largest cause of declining biodiversity
destruction and degradation of habitat
biotic homogenization
the process by which unique species compositions originally found in different regions slowly become more similar due to the movement of people, cargo, and species
biomagnification
process by which the concentration of a containment increases as it moves up the food chain
what has happened due to global warming
reduction in ice mass in the arctic and antarctica
where is global warming the highest
global warming will be the highest at the poles and heterogenous elsewhere
