Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
131 Cards in this Set
- Front
- Back
|
What is Ecology?
|
the study of the distribution and abundance of organisms and the factors and interactions that determine distribution and abundance
(where are they? how many are there? why?) |
|
|
Where do the roots of modern ecology lie?
|
natural history, human demography, biometry, and applied problems of ag and medicine
-hunters & gatherers -Aristotle -Herodotus & Plato |
|
|
What is Farr's Rule?
|
as the population density increases the death rate increases.
|
|
|
What are abiotic factors?
|
non-living chemcial and physical factors (temp, light, nutrients, water)
|
|
|
What are biotic factors?
|
living biological factors (other organisms, competition, predation)
|
|
|
What is an organism?
|
a single individual of a single species
|
|
|
What is a population?
|
individuals of the same species living in the same geological area
|
|
|
What is a community?
|
2 or more populations living in the same geological area
|
|
|
What is an ecosystem?
|
comprising the community together with with its physical enviornment
|
|
|
What is the mechanism for studying an ecosystem?
|
energy flow and cycling of nutrients among abiotic and biotic components
|
|
|
What is the mechanism for studying a community?
|
interactions among organisms
|
|
|
What is the mechanism for studying a population?
|
factors that affect population size and composition
|
|
|
What is the mechanism for studying an organism?
|
behaviors, environmental physiology, morphology
|
|
|
What is the mechanism for studying a tissue, cell, organelle, and/or molecule?
|
cell physiology, biochemistry
|
|
|
What are examples of ecological evidence?
|
-observation and monitoring in the natural environment
-manipulated field experiments -controlled lab experiments -math models |
|
|
What is the goal of ecology?
|
to observe patterns, describe processes, and use this information to predict, manage, and control
|
|
|
What is a p-value?
|
(probability levels)
-measures the strength of conclusions being drawn |
|
|
What is the null hypothesis?
|
assumes that there is no association between the two variables
|
|
|
Why does a species occupy a specific area?
|
-it evolved there
-it evolved somewhere else and dispersed to that area |
|
|
Why does a species not occupy a specific area?
|
-it evolved elsewhere and never dispersed there
-it was once present but is no longer there |
|
|
What are large scale distribution patterns (bio-geographic regions)?
|
-based on taxonomic similarities of organisms living there
-boundaries are set where species composition changes dramatically over short distances |
|
|
What are large scale distribution patterns (climate)?
|
-average atmospheric conditions found over time (temperature, precipitation, wind velocity)
-varies because of differences in the amount of solar energy |
|
|
What are large scale distribution patterns (biomes)?
|
-climate determines the distribution of biomes
-terrestrial biomes are based on the structure of their dominant vegetation -aquatic biomes are based on their physical/chemical differences -in each biome, vegetation has similar traits, but may not be evolutionarily closely related |
|
|
What is a transplant experiment?
|
-the major conceptual techniques used to determine the factors limiting distribution
-move organism and see if it can survive and reproduce in the new environment -follow through at least one generation |
|
|
What does it mean if the transplant is successful?
|
the potential range of a species is larger than its actual range
|
|
|
What does it mean if the transplant is unsuccessful?
|
potential range of a species is the same as the actual range
|
|
|
If the transplant is successful, why might the species not live there?
|
-lack means of transport (dispersal)
-can move but choose not to (habitat selection- area is inaccessible or unrecognizable as living space) |
|
|
If the transplant is unsuccessful, why can't the species survive there?
|
-limits imposed by other species (predators, competitors, parasites, disease)
-positive effects of interdependent species -some other chemical/physical factor |
|
|
What is dispersal?
|
the movement of organisms from one geographical location to another
|
|
|
What is the Southern California Intertidal Community example?
|
**dispersal**
hypothesis: -barnacles can get south but die -point conception is a barrier to larval dispersal results -barnacles survive in control and transplant. *point conception is a barrier |
|
|
What happened in the Tasmanian Blue Gum (Eucalyptus) example?
|
**dispersal**
-introduced in CA for railroad ties -no native predators, out competes natives -favorable abiotic enviornment *barrier to dispersal: breached by human introduction |
|
|
What happened in the Black rat and Mongoose example?
|
**dispersal**
-human introduction of black rats to hawaii (destroyed crops, native plants and native bird eggs) -Mongoose introduced from India to eat rats (both nocturnal: eat birds and eggs) *barrier to dispersal: breached by human introduction |
|
|
What is habitat selection?
|
(factors limiting distribution)
-organisms can move but choose not to live in certain habitats -distribution may be limited by the behavior of individuals in selecting their habitat |
|
|
What happened in the Dragonfly example?
|
**habitat selection**
-males occupy territories they can defend -determines where females will oviposit -smaller than available reproductive habitats *behaviorally contained habitats |
|
|
What happened in the Tree Pipit and Meadow Pipit example?
|
**habitat selection**
-both are ground feeders and feed on the same organisms -tree pipit is absent from treeless areas that the meadow pipit inhabits -tree pipits breed only in areas having one or more tall trees -meadow pipit has a similar song but it ends on the ground *behaviorally constrained habitats |
|
|
How are biotic interactions a factor limiting distribution?
|
-the local distributions of many organisms are limited by the presence of other organisms (competition, predation, parasites, disease)
|
|
|
What is competition?
|
(-,-) interaction
-can occur between 2 or more organisms or species that exploit the same types of limited resources and live in the same geological area -intraspecific: competition within species -interspecific: competition between 2 different species |
|
|
What is interference competition?
|
direct physical interaction over resources
|
|
|
What is exploitative competition?
|
indirect interaction over resources
|
|
|
What are natural patterns indicating competition?
|
1. When species B is absent, species A lives in a wider range of habitats (competitive release)
2. If competition is strong, the geographic ranges of the two competitors may not overlap but have sharp boundaries. |
|
|
What is predation?
|
(+,-) interaction
predation can limit the distribution of organisms: -direct consumption of prey -behavioral modifications of prey in the presence of predators |
|
|
What are abiotic factors (physical/chemical) limiting distribution?
|
-temperature and availability of water
-organisms have an upper and lower lethal limits to physical and chemical factors -solutions are either acclimination or adaption |
|
|
What are abiotic factors (temperature) limiting distribution?
|
-cells freeze at 0 C and proteins denature at 45 C
|
|
|
What are abiotic factors (water) limiting distribution?
|
-water is essential for life
-availability varies greatly among habitats -osmoregulation problems (lose or gain water) |
|
|
What are abiotic factors (light) limiting distribution?
|
-provides the energy that fuels nearly all ecosystems (photosynthesis)
-the intensity and quality of light limit the distribution of photosynthetic organisms -important to the development and behavior of many plants and animals that are sensitive to photo period |
|
|
What are abiotic factors (soil) limiting distribution?
|
-the physical structure and nutrient content of soils (limits the distribution of plants and animals that feed on them)
-the composition of substrate (affect water chemistry of streams and rivers which influences the residence of plants and animals) -in marine systems (soil structure in the intertidal zone and seafloors determine the types of organisms that can attach or burrow in those habitats |
|
|
What are abiotic factors (periodic disturbance) limiting distribution?
|
-catastrophic disturbances (fires, hurricanes, tornadoes and volcanoes) can devastate organisms and limit distribution
-frequent disturbance: may be predictable and organisms may be evolutionary adapted to the disturbance -infrequent disturbance: may be unpredictable and organisms will not have acquired the evolutionary adaption to them |
|
|
What are abiotic factors (pH and salinity) limiting distribution?
|
-affects the distribution of marine and freshwater organisms
-distribution is limited by high and low pH |
|
|
What are abiotic factors (currents and oxygen) limiting distribution?
|
-many organisms are dependent on wind and water currents to disperse their propagules or young
-oxygen can limit the distribution of organisms in lake |
|
|
What happened in the large and small barnacle example?
|
-as adults, barnacles are found in discrete zones (but larvae are spread everywhere)
-move large high (upper limit= dessication) -move small low (small lives if large is removed=competition) |
|
|
What happened in the predatory snail and large barnacle example?
|
-snail and barnacle are found in discrete zones as adults (barnacle larvae settle in all regions)
-cage experiment: in cage=barnacles lived outside cage= barnacles consumed (predation) |
|
|
What happened in the serpentine soil and goldfield flowers example?
|
-goldfield flowers are only found on serpentine soil and other plants are not found there
-other plants to serpentine=died (soil toxicity) -goldfield to sandstone soil=died when there were competitor but lived when other plants were removed |
|
|
What drives population dynamics (the change in population density through time and space)?
|
natality, morality, immigration and emigration
|
|
|
What is density?
|
the number of individuals per unit area or volume
|
|
|
What is density measured by?
|
-total counts (count all the individuals in the population)
-sub-sampling methods (estimate densities and total population size ex. mark and recapture) -indirect indicators (number of nests, fecal droppings, tracks, ect) |
|
|
What is the mark and recapture formula?
|
marked animals (2nd)=marked (1st)
total captured (2nd)=total population(N) |
|
|
What is natality?
|
birth rate= number of offspring produced per unit time
-depends on organism -birthrate= number of births/ size of reproductive population |
|
|
What is morality?
|
death rate= number of offspring dying per unit time
-death rate= number of deaths/ size of population at risk |
|
|
What is the immigration rate?
|
the number of individuals moving into an area per unit time
|
|
|
What is the emigration rate?
|
the number of individuals moving out of an area per unit time
|
|
|
Immigration and emigration are more important with....
|
smaller temporal/spacial scale
|
|
|
Birth/death rate are more important with...
|
larger temporal/ spacial scale
|
|
|
What drives population dynamics (the change in population density through time and space)?
|
natality, morality, immigration and emigration
|
|
|
What is density?
|
the number of individuals per unit area or volume
|
|
|
What is density measured by?
|
-total counts (count all the individuals in the population)
-sub-sampling methods (estimate densities and total population size ex. mark and recapture) -indirect indicators (number of nests, fecal droppings, tracks, ect) |
|
|
What is the mark and recapture formula?
|
marked animals (2nd)=marked (1st)
total captured (2nd)=total population(N) |
|
|
What is natality?
|
birth rate= number of offspring produced per unit time
-depends on organism -birthrate= number of births/ size of reproductive population |
|
|
What is morality?
|
death rate= number of offspring dying per unit time
-death rate= number of deaths/ size of population at risk |
|
|
What is the immigration rate?
|
the number of individuals moving into an area per unit time
|
|
|
What is the emigration rate?
|
the number of individuals moving out of an area per unit time
|
|
|
Immigration and emigration are more important with....
|
smaller temporal/spacial scale
|
|
|
Birth/death rate are more important with...
|
larger temporal/ spacial scale
|
|
|
What methods are used to identify how population size changes (dynamics)?
|
-direct observations (not always practical)
-view age structures (life tables and survivorship curves) -math models ( |
|
|
What is the formula for the simple population growth model?
|
Nt=No+B-D+I-E
|
|
|
What is needed for exponential growth?
|
unlimited resources!
dN/dt =rN (r=b-d) |
|
|
What happened in the Northern Elephant seal example?
|
**exponential growth model**
-close to extinction -hunting stopped: habitat and resources were abundant -exponential growth |
|
|
What happened in the European Rabbits example?
|
**exponential growth model**
-rabbits from England introduced to South Australia -each female can produce 6 liters of 10 rabbits each year -population increased exponentially -largest fence ever built failed |
|
|
What is the carrying capacity(K)?
|
the maximum population size that an environment can support
-varies over space and time |
|
|
What is the logistic growth model?
|
dN/dt=rN((K-N)/K)
|
|
|
How well does the logistic model fit the growth of natural populations?
|
-populations of very small organisms fit fairly well
-many populations do not stabilize at K and deviate from curve -predictions are only correct when: environment is constant, no predators, and no competition from other species |
|
|
Why does the logistic curve not fit well for most natural population growth patterns?
|
because it assumes that:
-each individual added to population has the same negative effect on population growth (ex. flamingos and isolated plants) -population approaches K smoothly (time lag) -populations are large and density is important in regulation (ex. insects and microorganisms) |
|
|
What is density dependent control?
|
factors that alter per capita birth/death rate in a population are dependent on population density (can stabilize population density)
-ex. parasitism, predation, competition can be density dependent |
|
|
What was the bubonic plague example?
|
**density dependent control**
-blood pathogen that exists in rats.. transmitted by fleas |
|
|
What is density independent control?
|
factors that alter per capita birth/death rates in a population are independent of population density (does not stabilize density)
-ex. physical/chemical factors: weather, drought, freezes, flood and fire |
|
|
What happened in the monarch butterfly example?
|
**density independent control**
-migrate from canada to mexico -logging removed temperature buffer -freeze killed millions of monarchs |
|
|
What is a stable population?
|
(birth rate=death rate)
-if perturbed population will return to initial density -stabilizing forces dampen population fluctuations -density dependent control |
|
|
What is an unstable population?
|
-if perturbed population may not return to initial density
-destabilizing forces enhance population fluctuations -inverse density dependents (long time lags) |
|
|
What are metapopulations?
|
population is divided into discrete sub-populations which are connected by immigration and emigration
-growth and reproduction within patches -migration between patches or colonization of empty patches |
|
|
What happens to metapopulation when migration increases, decreases and remains constant?
|
-increases: local population fluctuations are dampened
-decreases: local population fluctuations are enhanced (increases probability of extinction) -intermediate: shifting mosaic of occupied and unoccupied patches (persistence) |
|
|
What is the metapopulation dynamics model?
|
(how does the fraction of occupied sites (f) change with time?)
f=fraction of sites occupied (proportion of patches that contain populations) if f=1 all sites are occupied if f=0 all sites are unoccupied (extinct) df/dt=(probability of local colonization)(1-f) - (probability of local extinction)(f) I>E then f increases |
|
|
What happened in the Bay checker spot butterfly example?
|
**metapopulations**
-caterpillar larvae feed on specialized plants that grow on serpentine soil -in drought years, most of these plants die, kills larvae -one drought, 3 metapopulations became extinct -largest subpopulation became new colonists |
|
|
What is mutualism?
|
(+,+) both species benefit from the association
-ex. large African mammals & tick birds and sea anemone & zooxanthellae |
|
|
What is commensalism?
|
(+,0) one species benefits from the association, the other is unaffected
-ex. shark & remora and cockroach & human |
|
|
What is competition?
|
(-,-) both species are harmed from the association
-ex. lion and hyena |
|
|
What is predation?
|
(+,-) one species benefits from the association and the other is harmed
-ex. humans & parasites (parasitism), tapeworms, and intestinal round worms |
|
|
What is the Lotka-Volterra competition model?
|
dN1/dt1=r1*N1((K1-N-alpha*N2)/K1)
this gives the population growth of species one in competition with species 2 |
|
|
What are possible outcomes of competition?
|
1. both species coexist (stable or unstable equilibrium)
2. species one becomes extinct 3. species two becomes extinct |
|
|
How do theoretical models for competition apply to natural systems?
|
ex. Gause
-competition between 2 species of yeast -grew populations in isolation (logistic growth) -then grew 2 populations together -species 1 growth unchanged (logistic) and species 2 went extinct *fit data to lotka-volterra equations -species one had a higher competitive effect (beta>1) -species 1 produced more alcohol and waste then species 2 |
|
|
What is the competition exclusion principle?
|
no two species can occupy the same ecological niche simultaneously (complete competitors can not coexist)
|
|
|
What is a niche?
|
the biological role of an organism within an environment
|
|
|
What is a fundamental niche?
|
the multitude of conditions in which an organism can survive and multiply
|
|
|
What is a realized niche?
|
where an organism actually exists due to ecological constraints
|
|
|
What happened in the parasitic wasps example?
|
**competition- competitive exclusive**
-competitive exclusion displaced prior species of wasps but now 2 species coexists but in different habitats in So Cal |
|
|
Why doesn't competitive exclusion occur?
|
1. unstable environments (never reach equilibrium, low density of organisms)
2. environments in which species do not compete 3. fluctuating enviornments that reverse the direction of competition before extinction occurs |
|
|
What are the four types of predation?
|
-herbivory
-cannibalism (KESHA) -parasitism -carnivory |
|
|
What is the formula for the Lotka-Volterra Predator-Prey model?
|
prey population growth:
dN/dt=rN-(aPN) predator population growth: dP/dt=faPN-qP |
|
|
What are the predicted outcomes of the Lotka-Volterra Predator-Prey model?
|
-equilibrium
-oscillations -extinction |
|
|
What happened in Gause's Laboratory Predator Prey example?
|
D(predator) and P(prey)
-D exterminated P and D died of starvation -no oscillations |
|
|
What happened in Utida's laboratory predator prey example?
|
azuki bean weevils (host) and parasitic wasps (parasite)
-interaction produced cycles (112 generations and 14 complete oscillations) -oscillations converged and wasps died out |
|
|
What happened in the Sea Lamprey example?
|
-canal linked Great Lakes to Niagara Falls
-first lamprey discovered in Great Lakes -decimated lake trout -lamprey control efforts (dams) -trout population increased |
|
|
What happened in the snow shoe hare and lynx example?
|
-hare decline due to decrease in birth/growth rate and increase in morality (predation)
-increased number of hares decreases food supply, increases exposure and predation -as predation increases, increases growth/birth rate and decreases hare population |
|
|
What are community characteristics?
|
-trophic structure
-species diversity -dominance -growth form and structure |
|
|
What is the individualistic hypothesis (community)?
|
communities are chance assemblages of species with similar abiotic requirements
|
|
|
What is the interactive hypothesis (community)?
|
communities are assemblages of dependent closely linked species
|
|
|
What is species diversity?
|
richness(number of species in a community) + evenness(relative abundance of species in a community)
|
|
|
What is the Shannon Weaver (Wiener) Diversity Index?
|
H= -sum(Pi*ln(Pi))
Pi= proportion of individuals contributed to total abundance |
|
|
The wider the average niche breadth, the...
|
fewer the number of species in the community (extinction via competitive exclusion)
|
|
|
The narrower the average niche breadth, the....
|
more species in the community (coexistence via resource partitioning)
|
|
|
How does intraspecific competition affect the short and long run?
|
short- decreases diversity (ecological)
long- increases diversity (evolutionary) |
|
|
What is a keystone species (competitor)?
|
a species influences on the community is greater than expected that would be expected on the basis of its abundance
|
|
|
What happened in the keystone Starfish example?
|
-removed starfish from patches for 5 years
-space is a limiting resource (28 species coexist) -in year 3: only barnacles and mussels left -in year 5: only mussels present -mussels are competitive dominant (excludes others from space) *predator mediated coexistence |
|
|
What is a disturbance?
|
an event that removes organisms that alters resource availability
-small scale (tree falls, rock flipped over) -large scale (volcano, fire) |
|
|
What is the intermediate disturbance theory?
|
1. When a disturbance is severe and frequent community is exposed of good colonizers with high reproductive rates
2. When a disturbance is mild and rare community is composed of good competitors |
|
|
Species diversity is highest when disturbance is....
|
intermediate
-allows both colonizers and competitors to co exist |
|
|
What happened in the Ellwood Boulder Field example?
|
-boulders of intermediate size had more species than small or large boulders
-glued small boulders in place (reduced disturbance) -glued small boulders had higher species richness than loose small boulders |
|
|
What is succession and what are the two types?
|
-transition in species composition over time
-primary succession=(bare soil, no organisms) -secondary succession=(soil, some organisms) |
|
|
What is the succession pathway?
|
1. early successional communities (r selection)
-good dispersers and high reproductive rates 2. late successional communities (K selection) -good competitors and exist near carrying capacity |
|
|
What is the equilibrium theory of island biogeography?
|
species richness is positively correlated with island size and negatively correlated with distance from mainland
|
|
|
What happened in the island biogeography example?
|
Flordia- 6 islands killed anthropods
-equilibrium within a year -furthest island from mainland had fewest species -equilibrium numbers similar between pre and post fumigation but species composition was different |
|
|
What is the equilibrium view?
|
1. communities are structured by biotic interactions (competition, ect)
2. communites display global stability 3. niche diversification determine species diversity |
|
|
What is the non-equilibrium view?
|
1. communities composition is always changing and is never in balance
2. no global stability 3. communities are patch works of disturbance. colonization and dispersal determine species diversity |
