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75 Cards in this Set
- Front
- Back
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interspecific interactions are ____ based. |
genetically |
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what are the 6 types of interactions? |
-predation -herbivory -competition -commensalism -mutualism -parasitism |
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what are the effects on interacting populations? |
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explain predation: |
interaction between predatory animals and the animal prey they consume |
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explain herbivory: |
interaction between herbivorous animals and the plants they eat |
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explain the difference between generalists and specialists: |
generalists: prey on a lot of things
specialists: only prey on one specific thing |
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why do we have diverse adaptions? |
to select, locate, capture, and ingest an appropriate diet |
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what is the optimal foraging theory? |
-mathematical models that predict an animal's diet |
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what do you need to balance? |
cost and benefits |
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what is the relationship between prey density and predator food choice? |
low prey density-- less selective
high prey density-- more selective |
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what are the 9 modes of defence: |
1) size 2) eternal vigilance 3) avoiding detection 4) thwarting attacks 5) spines and amour 6) chemical defence 7) warnings 8) mimicry 9) no perfect defence |
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explain size: |
-too small to be considered food -so big that few, if any, predators can suceed in attaching and killing prey |
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explain eternal vigilance: |
dont move and keep a sharp lookout |
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explain avoid detection: |
many animals are cryptic, camouflaged so that a predator does NOT distinguish them from the background |
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explain thwarting attacks: |
-defensive -run fast -hide -offence |
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explain spines and armor: |
-physical defense |
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explain chemical defense: |
-plants and animals make themselves chemically unattractive
-smelling or tasting bad -dangerous toxins |
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explain warnings: |
-poisonous or repellant species may advertise their unpalatability--> aposematic |
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what are the 2 types of mimicry: |
bastien and mullerian |
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explain bastien mimicry: |
-appearance resembling a poisonous species -mimic-model
-a bee has a stinger and a drone fly will mimic its color to look like it |
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explain mullerian mimicry: |
-two unpalatable (poisonous, dangerous) species with similar appearance
-reinforces the fact to stay away |
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explain perfect defence: give example |
-predators may evolve adaptations to counter prey defense
ex.) a rat will grab a beetle from the head bc there is poison in the back
THIS IS WHY NO DEFENCE IS PERFECT |
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def of interspecific competition: |
two or more populations using SAME limiting resources |
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what are 2 types of interspecific competition? |
1) interference competition 2) exploitative competition |
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def of interference compeition: |
one species HARMS another species directly |
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def of exploitative competition: |
-equal or greater than 2 populations use SAME limiting resource -one species REDUCES resource availability to others |
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describe the interspecific competition model: |
-individual species are logistic (s shape)
-Together, one population INCREASES and the other population DECREASES -they both grow less than what they did on their own |
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what is the competitive exclusion principle? |
populations GREATER than or EQUAL to 2 cannot coexist indefinitely if they rely on same limiting resources in the same manner
therefore, one species will outcompete the other |
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What is the difference between a fundamental and realized niche of a species? |
fundamental niche: the range of conditions and resources it could tolerate and use
realized niche: the range of conditions and resources it actually uses
-realized is less than fundamental because there is competition (overlap) -ASYMMETRICAL COMPETITION |
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what is resource partitioning? |
-use of different resources or in in different ways -coexistence
ex.) plants using water and nutrients at different levels of soil so there is no competition although they are sympatric (live in the same place) |
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what is character displacement? |
-characteristics to be more divergent in sympatric populations than in allopatric populations of 2 species -allows closely related species to coexist in societies without creating different species, breeds or overgrowing the population of a species. -allows for co-existence w/o competition |
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def of endoparasites: |
live WITHIN host |
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def of ectoparasites: |
live on EXTERIOR of host |
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def of parasitoids: |
-a feeding habit of insects -between true parasitism and predation |
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what are the 2 hypotheses regarding the nature of ecological communities:
how does interspecific competition affect nature of ecological communities? |
1) interactive hypothesis
2) individualistic hypothesis |
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explain interactive hypothesis: |
in mature communities, species are at equilibrium and, if disturbed, will return to the pre-disturbed state |
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explain individualistic hypothesis: |
communities do NOT achieve equilibrium but rather are in a steady state of flux (change) in individual responses to environmental change
-each response will be up to the individual |
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does data support interactive (curve alignment) or individualistic (no alignment) hypothesis? |
individualistic |
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what are ECOTONES? |
borders between adjacent communities, they are sometimes wide transition zones (species rich--> a lot of resources from both sides) -also may have sharp boundaries if critical resource/factor is discontinous |
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what kind of environment would tall vegation with complex physical strcture> |
WARM, MOIST |
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where would short vegetation and simple physical structure grow? |
stressful environments |
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what 2 things does species diversity reflect? |
1) species richness 2) relative abundances of species |
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what are the levels of trophic structure? |
-primary producers (autotrophs) -consumers (heterotrophs)
-detritivores (animals) |
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explain primary producers (autotrophs): |
capture sunlight and convert it to chemical energy |
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explain consumers (heterotrophs) |
-primary consumers are herbivores -secondary and tertiary consumers are carnivores or omnivores (animals/ plants) |
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explain detritivores (animals): |
-scavengers -decomposers (bacteria and fungi) -feed on dead or dying organic matter |
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why is food chain better than a food web? |
in a chain, if u remove one thing, the chain will collapse in a web, if u remove one thing, the web still still stand **the more complex web, the more stable it is** |
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how do predators increase species richness?
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by REDUCING pop. size of most successful prey, this makes room for other species to grow and become the "new" prey
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what is a keystone species?
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they have a greater effect on community structure than their number suggest |
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How do disturbances affect the characteristics of a community?
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-frequent disturbances keep some ecological communities in a constant state of flux -moderate levels of disturbance may foster high species richness -the more diverse you are, the higher chance you'll survive distubances |
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what is the intermediate disturbance hypothesis? |
-disturbances at intermediate intensity and frequency allow r-selected (to arrive) and K-selected (to survive) species to occupy a site -increase species richness -increases growth and recruitment |
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explain environmental disturbances: |
-may eliminate populations from the community -some communities experience so many disturbances that their species never reaches equilibrium |
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what is succession? predictability? |
-change in ecosystem over time -somewhat predicatable
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what are the types of succession? |
primary and secondary
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explain primary sucession: give example |
begins on habitats without soil
ex.) volcanoes and glaciers
-ecologists document primary succession on newly exposed rocks and soil (from ice, ice melting, grass and trees |
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explain secondary sucession: |
occurs where a community existed in past
-existing vegatation was destroyed or disrupted |
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what is a climax community in early succession ? |
-species richness rises rapidly, changes quickly -includes short lived r-selected species |
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what is a climax community in late sucession? |
-includes long lived K-selected species -some communities eventually achieve a relatively stable climax state |
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How does species interactions affect succession? |
the more species that interact, the faster and sooner succession will occur |
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what are the 3 hypothesis that explain how species interactions affect succession? |
1) facilitation hypothesis 2) inhibition hypothesis 3) tolerance hypothesis |
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explain facilitation hypothesis: |
-species modify local environment, making it less suitable for themselves BUT more suitable for NEW colonizers
-leads to next successional stage -ONE SPECIES MAKE CHANGES THAT HELP OTHERS |
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explain inhibition hypotheses: |
-each successional stage dominated by first colonizers -new species are prevented from occupying community by species already present -eventually dominant species die of old age or a disturbance reduces their numbers and are replaced - ONE SPECIES NEGATIVELY AFFECTS OTHERS
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explain tolerance hypothesis: |
-as more species arrive, resources become limiting and competition increases -competitively superior species replace competitively inferior species -SPECIES TOLERATE ONE ANOTHER |
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patchiness in environmental conditions and small-scale disturbances may result in _________ of relatively undisturbed and recently disturbed sites |
MIXTURES |
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what 2 patterns/variances of species richness? |
1) latitudinal trends 2) island patterns-- Equilibrium Theory of Island Biogeography |
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explain Latitudinal Gradients in Species Richness? |
communities near the equator have higher species richness than those near poles |
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what are the historical explanation for latitudinal gradients? |
-benign climate in tropics allows more generations per year -less migration leads to less gene flow between isolated population -higher speciation rates -less severe disturbance in tropics |
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what are the ecological explanation for latitudinal gradients? |
-more abundant, predictable, and diverse resources in tropics (carrying capacity increases) -longer and more favourable growing season leads to higher productivity -greater complexity supports greater diversity (more stable, can withstand more disturbances) |
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what is the prediction of the equilibrium theory of island biogeogrpahy? |
-number of species on an island balanced between immigration of new species and extinction of species already present
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what are factors influencing species richness? |
-large islands have more species than small islands -islands near mainland source have more species than distant islands (the further ur from the mainland, its harder for new species to migrate) |
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what is the relationship between size of island and equilibrium #? |
as size of island increases, equilibrium # increases
-larger island can support more diverse species |
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relationship between distance from mainland and equilibrium #? |
increase distance, decrease equilibrium #
-organisms closer to island are more likely to immigrate to the island |
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relationship between distance and immigration |
as distance increase, immigration decreases |
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relationship between species richness and immigration |
as species richness decreases, immigration increases |
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relationship between size and species richness |
as size increases, species richness increases |
