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62 Cards in this Set
- Front
- Back
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define succession
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change in species composition in communities over time
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define disturbance
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Events that injure/kill some individuals and create opportunities for other individuals
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define stress
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Abiotic factors that reduce growth, reproduction, or survival of individuals
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what are some things that influence community change?
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biotic and abiotic factors such as diseases, ecosystem engineers, and keystone species
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define ecosystem engineers
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Create, modify or Maintain physical habitat for themselves and other species
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describe the graph Intensity vs. frequency
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define primary succession
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Colonization of habitats devoid of life after a large disturbance
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give an example of primary succession.
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volcanic rock after a volcano eruption
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define secondary succesion
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Reestablishment of a community in which some, but not all, organisms have been destroyed.- after small disturbances
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define facilitation
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Earlier species modify the environment in ways that benefit later species
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define inhibition
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Earlier species modify the environment in ways that hinder colonization of later species
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define alternative stable states
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Sometimes different communities develop in the same area under similar environmental conditions
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when is a community considered stable?
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whent it returns to its original state after perturbation
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what did Sutherland do in his experiment in 1974?
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-suspended ceramic tiles from a dock to allow them to be colonized by invertebrates
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what were the results of the Sutherland experiment in 1974?
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the domination of the ceramic tiles depended on the time of year; was seasonal
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define hysteresis
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an inability to shift back to the original community type, even when original conditions are restored
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what do the traits of stable communities include?
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resistance to perturbation and resilience
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define resilience
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the ability to recover after a perturbation
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Why do we care about the factors that influence diversity and productivity?
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-production of food/water -water filtration and nutrient/waste cycling -flood control -pollination, fisheries |
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why do species occur when and where they do? (aka what does a membership in a community depend on?)
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variation in regional species pools, abiotic conditions, and species interactions
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what are some ways that species overcome regional dispersal limitations?
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-brown tree snakes on Guam would get into airplanes and get a ride to America -organisms would get introduced into new areas via ballast water that ships take on |
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what are some ways that species overcome abiotic dispersal limitations?
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-A species may be able to get to a community but be unable to tolerate the abiotic conditions -a lake might not support organisms that require fast-flowing water. |
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what are some ways that species overcome species interaction dispersal limitations?
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Coexistence with other species is required for t his -Species may be excluded by competition, predation, parasitism, or disease. |
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when does biotic resistance occur?
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when interactions with the native species exclude the invader
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why are some communities more diverse than others?
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Resource partitioning is theorized to reduce competition and increase species diversity
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what leads to competitive displacement?
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high resource overlap
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define competitive displacement
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The best competitor uses the limiting resources, reducing the weaker competitor’s population growth to the point of extinction
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define resource partitioning
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Competing species are more likely to coexist if they use resources in different ways
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define resource ratio hypothesis
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species coexist by using resources in different proportions
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what happens if disturbance, stress, or predation keeps the dominant competitor from reaching carrying capacity?
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competitive exclusion cannot occur, and coexistence will be maintained
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define intermediate disturbance hypothesis
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there will be more species diversity when there is an intermediate level of disturbance, stress, or predation; THIS IS NO LONGER TRUE
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Does increased diversity = increased community function?
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yes
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define redundancy hypotheses/rivet model
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as species richness increases, so does community function until it reaches a threshold
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define complementarity hypothesis
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as species richness increases, community function increases *Species can be continually added without saturation and Strength and breadth of functions don’t vary |
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example of functional redundancy
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Until a disease wiped out all urchins within a year, then coral cover significantly and drastically declined
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what are driver and passengers?
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Drivers have large ecological impacts and passengers few impacts
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What are some types of species that ecologist would consider “drivers”?
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define biogeography
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the study of patterns of species composition and diversity across geographic locations
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define endemic species
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Those that occur in a particular geographic location, and nowhere else on earth
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what are the spatial scales?
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-global -regional -landscape -local scale |
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define local scale
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equivalent to a dommunity -interacting group of various species in a common location |
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what is alpha diversity?
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this is how many species are within this local site
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what is beta diversity?
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this is the change in species number on landscape scale -connects local and regional scales |
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define landscape scale
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topographic and environmental features of a region
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what is the "equation" for beta diversity?
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Beta=(total # of species)/(mean alpha) |
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define mean alpha
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number of species divided by number of sites
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define regional scale
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areas with uniform climate
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define gamma diversity
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total number of species at large spatial scales
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continental drift and biogeographic regions
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-pangaea -laurasia -gondwana |
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define pangaea
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all landmasses made up as one large continent
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define laurasia
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north America, Europe, and asia
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define gondwana
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south America, Africa, India, Antarctica, and australia
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define vicariance
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evolutionary separation of species by barriers such as those formed by continental drift
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what happens between species diversity and latitudes? |
Species diversity often increases towards decreased latitudes
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the larger the area...?
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the higher the species richness
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the larger the distance between area...?
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the lower the richness in the sink area
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Is species diversity (positively/negatively) related to latitude?
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negatively
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what are patterns of diversity controlled by?
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-speciation -extinction -dispersal |
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species diversification rate=?
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speciation-extinction
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where is speciation rate higher?
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in the tropics
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why is the speciation rate higher in the tropics?
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-Low SA/V ratios at the poles facilitate heat retention -High SA/V ratios in the tropics facilitate heat loss |
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