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84 Cards in this Set
- Front
- Back
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Biodiversity
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the degree in variation in life forms...or the number of biological elements in a defined area
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Local (alpha) richness
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number of species in a small area of uniform habitat
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Regional (gamma) richness
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total number of species within the region, minus two species common to two or more patches (avoid double count of species)
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Beta Diversity
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degree of difference in species ("turnover") among patches, compares number of species unique to each patch
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Large Scale Patterns in Diversity
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Latitudinal gradient, topogrpahical relief, fronts of abrupt change, peninsular decreases, larger area
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History as Diversity Gradient
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more time and bigger area= (most likely) more species
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Spatial Heterogenity as Diversity Gradient
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physically and biologically complex habitats usually result in more species
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Biotic Interactions as Diversity Gradient
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interactions in the tropics generally more intense ie competition, predation, mutualistic relations
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Climate and Variability as Diversity Gradient
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fewer species can tolerate climatically unfavorable or climatically variable environments
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Habitat Islands
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isolated bits of favourable habitat in a "sea" of different or unfavorable habitat
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Species-Area Relationship (E.O. Wilson)
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convergence at large area sizes ie slope of the species-area line is higher for islands
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Equilibrium Theory of Island Biogeography
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MacArthur & Wilson: species richness is a balance between immigration and extinction
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Rate of Immigration
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rate of immigration of new species decreases as the number of species on the island increases
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Rate of Extinction
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rate of species extinction goes up as the number of species on the island increases
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Area Effect of Equ. Theory
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larger islands have more species than smaller islands (<extinction)
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Distance Effect of Equ. Theory
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more remote islands have fewer species (<immigration)
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Landscape Ecology
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the study of the relationship between spatial pattern and ecological process
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Landscape structure
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size, shape, composition, number, and position of different elements (patches, communities, ecosystems) in a landscape mosaic
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Landscape Processes
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the flow of organisms, energym and materials among landscape elements --> influenced by landscape structure
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Metapopulation
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a set of spatially distinct sub-populations in patches linked through occasional dispersal
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Source-Sink Model
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all patches are not equal (size, isolation, quality)
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Source
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usually hgih quality patches with abundant resource; births> deaths, and extras to disperse other patches
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Sink
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usually low quality patches with few resources; births > deaths and the populations only survives due to immigration elsewhere
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Landscape Model
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considers spatial and ecological relations of patches to each other, but alse the habitat quality of the matrix
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Matrix
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the dominant, connected ecosystem on the landscape
-quality of matrix influences movement -neighboring patches may provide complementary resources |
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Corridors
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actual value of corridors is highly-variable; effectiveness varies with species and habitat, and may have side-effects, can also act as filter
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Succession
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primary and secondary succession
sequential, directional, and relatively predictable change thru time in community composition, and associated abiotic properties, following disturbance |
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Climax Community
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the ultimate association of species after succession
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Disclimax Community
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require continual disturbance to persist
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Primary Succession
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succession on newly formed or exposed sites, which lack previous biotic influences --> no organic matter, typically no soil
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Secondary Succession
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succession after an existing ecosystem is disturbed -->previous ecosystem influences subsequent processes
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Autogenic Changes
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environmental changes brought about by organism within the community --> a common feature of terrestrial succession
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Hubbard Brook Ecosystem Study
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BACI design (before, after, control, impact) study to measure a ecosystem before and after a change
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Outcome of Succession
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not predictable; dependent on local interactions and conditions, may not result in same climax community even under similar conditions
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Facilitation
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-only certain pioneer species can survive in early succession
-modify environment for others -earliest pioneer species die to make room for mid species |
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Tolerance
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-any species can colonize in succession
-early species simply change environment -later species tolerate environment better -climax community reached when species tolerance is equal |
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Inhibition
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-any species can colonize in early succession
-early species inhibit colonization by later species -later only colonize if space opens -climax community is dominant species |
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Ecosystem Changes during Succession
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1.Change in species composition
2. Increased structure complexity 3. Increased food web and energy flow complexity 4. Increased biomass 5. Increased nutrient conservation 6. Ecosystem reaches stability |
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Stability
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absence of change b/c no disturbance to cause change
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Resistance
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aspect of stability, ability to maintain community structure/function in the face of disturbance
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Resilience
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aspect of stability, ability t return to original structure/function after disturbance
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Invasion Resistance
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less available niche space and more effective use of resources
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Averaging Effect
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averaged responses of many species will act as a buffer against disturbances
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Insurance Effect
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many species mean more redundancy in the community
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Disease/pest resistance
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harder for the disease/pest to specialize
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Components of an Ecosystem
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biogeochemistry, energy, organisms
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Linear Food Chain
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simplest abstraction of trophic relationships within a community
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Energetic Hypothesis
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length is limited by inefficiency of energy transfer
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Primary Productivity
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rate of primary production, supplies carbohydrates needed to build tissues, function, and reproduce (usually is photosynthesis)
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Gross Primary Production (GPP)
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total assimilation of energy by autotrophs, regardless of costs
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Net Primary Production (NPP)
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energy available after respiration, amount of energy left over after the autotrophs have met their own needs NPP= GPP- respiration
(NPP= Photosynthesis- respiration) |
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Controls of Productivity
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Light, climate, nutrients, trophic cascade, bottom-up control, top-down control
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Trophic Cascade
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when effects of predation extend (indirectly) to lower trophic levels
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Bottom-up Control
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when lower trophic levels (or nutrients) determine "size" of level above
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Top-down Control
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when higher trophic levels determine "size" of levels below
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Efficiency of Energy Transfer
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fixation and transfer of energy thru the ecosystem is governed by the laws of thermodynamics (when energy is transferred, some is lost)
(NPP/GPP) x 100 |
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Fates of NPP
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consumption by herbivores
death and degradation |
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I
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Ingested NPP (I)
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A
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Assimilated NPP (A)
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W
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Egested NPP (W)
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R
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Respired NPP (R)
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Secondary Production P
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I-W-R= P
remaining NPP is used for growth or reproduction |
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Gross Product Efficiency
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represents overall energetic efficient of biomass production within a trophic level
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Detrital Food Chain
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source of energy is dead organic matter (decomposers)
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Assimilation Efficiency
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the proportion of consumed energy that is actually assimilated (can actually be used)
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Net Product Efficiency
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the efficiency with which assimilated energy is incorporated into growth, storage, reproductive
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Gross Production Efficiency
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the overall efficiency of biomass production within a trophic level
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Ecological Efficiency
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the % of energy actually transferred from one trophic level to the next
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Residence Time
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how long does it take for energy to move through trophic levels
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Biogeochemistry
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biotic and abiotic components of the ecosystem are linked
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Nutrient Inputs
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-nutrients with a gaseous cycle enter via atmosphere
-nutrients with a sedimentary cycle enter via weathering og rocks-->soil formation |
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Nutrient Ouputs
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loss to atmopshere via respiration, transport via biota, leaching from soil/sediment/detritus, erosion/harvesting/fire
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Global H2O Cycle
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-main process is evaporation, transpiration and perciptation
-driven by solar radiation -major pools ocean (97%), glaciers (2%), groundwater (0.6%) |
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Nutrient Cycles
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phopshorus, nitrogen, and carbon most important cycles
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Phosphorus Cycle
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-not common but needed
-major pools are mineral |
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Nitrogen Cycle
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-not common but highly needed
-fixation of N2 into usable forms -major pool is atmospheric |
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Carbon Cycle
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-major pools: carbonate rocks, ocean, hydrocarbons, organic material in sediment, plants
-3 main processes: assimilation, diffusion, dissolution, combustion |
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Assimilation
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usually by photosynthesis from the respiration of other organisms
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Diffusion
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exchange between atmosphere and ocean
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Dissolution
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Dissolution and sedimentation in aquatics
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Combustion
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burning of fossil fuels
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Bioturbation
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prevents stratification of nutrients, more vertical homogenity
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Nutrient Spiralling
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in streams and rivers, some aspects of the ecosystem itself are moving downstream
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Spiralling length
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velocity x cycle time
short spiralling: high retentiveness long spiralling: low retentiveness |
