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82 Cards in this Set
- Front
- Back
open community
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edges blend into adjacent communities
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closed communities
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borders are sharp and defined
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keystones species are usually located at the ____________ of the food chain.
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top
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alpha diversity
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compared within one system
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beta diversity
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compared between 2 different sites in the same region
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gamma diversity
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compared between different regions
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community
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an assemblage of interacting populations of different species that forms an identifiable group. They can be open or closed, autotrophic or heterotrophic.
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species composition
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the most basic property of any community. includes the kinds and types of each species present, as well as the numbers and relative abundance of each species
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dominant species
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most common species in any community
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keystone species
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those that are not extrememly common, but which exert a large amount of control over the entire community
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dominance
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a measure of numbers in any community
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relative abundance
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a measure of the proportion of each species relative to the whole community
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species diversity (biodiversity)
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a combination of dominance and relative abundance. takes into account species richness and and species eveness
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species richness
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the number of species present
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species evenness
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the degree to which the individuals are allocated among the different species
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`diversity is a measure of _______________ on the community
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variation
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factors that promote diversity in a community
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1. complexity and size (unsaturated vs saturated)
2. proximity to the equator 3. strong resource diversity 4. level and kind of competition- narrow niches |
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disturbance
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a change in environmental conditions that causes a change in the component species within a community. communities that receive a moderate amount of disturbance are actually benefited. Raise complexity, raise diversity.
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diversity is important because . . . .
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it promotes health, vigor, productivity, and stability within and community
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stability
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the ability of a community to handle disturbance, includes both resistance and resilience. High diversity will bring about stablilty because the loss of any one component can be compensated for by another component.
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resilience
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how well a community can bounce back
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resistance
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how well a community can resist change
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all communities possess a _______________ structure.
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physical (spatial)
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strata
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most communities are organized into vertical layers. This is known as stratification.
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in terrestrial communities, the strata themselves are caused by the ____________
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vegetation. note that grasslands have less strata than forests
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in aquatic communities, the strata are causesd by teh level of ____________
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of light penetration, as well as oxtgen and temperature gradients.
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zone of decomposition and regeneration
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the bottom strata
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zone of energy fixation
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upper stratum
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degree of vertical layering
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has a pronounced effect on the diversity of animal life in any community
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zonation
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the horizontal pattern of change in a community
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gaps
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openings in the canopy caused by teh death of a canopy tree
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horizontal patchiness
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adds to habitat complexity
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fragmented habitat
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severely clumped distribution of vegetation can lead to ...
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turnover rate
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the rate at which one species is lost and a replacement is gained
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equilibrium theory of island biogeography
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relates teh rate of colonization to the rate of extinction
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corridors
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can help fragmented habitats develpop better, although many species require a minimum critical size of habitat
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edge
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is a region where two or more communities meet. some species prefer edge, others prefer the interior of the habitat, and still others have no preference. edges can be induced or inherent, abrupt or gradual.
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ecotone
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a region where two or more communities not opnly meet, but integrate and blend together. they are usually areas of high diversity and complex relationships
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edge effect
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almost all edges are very rich regions with much diversity. in general, large, high cointrast edges that are adcancing into each other are of greatest value; however,too much edge effect can be detrimental to the ecosystem.
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scale-dependent community classification
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differences in community structure increase as we consider larger and larger areas
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temporal structure
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refers to daily and seasonal sycles of activity within the community. the most striking example of this is seasonal change.
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hopkin's bioclimactic law
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relates the occurence of spring events to latitude, elevation, and longitude.
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trophic (feeding) levels
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food chains, food webs. (this is known as trophic structure)
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chemical ecology
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the study of the production of chemical compounds by organisms and the uptake or reception of these chemical compounds by other organisms.
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open community
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edges blend into adjacent communities
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closed community
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borders of edges are sharp and defined
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saturated community
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most/all niches are full. This is good for diversity.
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unsaturated community
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many unfilled niches
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extreme regions have ___________ diversity
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low
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layers of an aquatic ecoysystem
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epilimnion, hypolimnion, metalimnion
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emergent trees
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grow above the canopy
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light based layers of an aquatic ecosystem
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littoral, limnetic, profundal zones
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thermocline
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rapid decline in temp
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four factors that contribute to diversity
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complexity and size (saturated vs unsaturated), proximaty to the equator, strong resource diversity, level and kind of competition (narrow niches)
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communities
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groups of interacting population of different plant and animal species
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integrated (organismal) concept
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community composition is predictable. community is a while, stable, and orderly. coactions are classified.
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individualistic concept
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community composition is not predictable. coexistance is the result of similar requirements and tolerances
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non-directional changes
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do not alter community permanently. short term and cyclic. ex: daily, seasonal changes.
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directional changes
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alter the community permanently. long-term, non-cyclic. ex: extinction, succession.
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replacement changes
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are those involving the replacemtnt of one individual by another of the same or different species
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cyclic replacement
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involves any kind of replacement activity that occurs in a continuous cycle, such as canopy replacement.
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fluctuations
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alterations in community structure or composition that occur as a result of shifts in habitat factors. habitats in whihc fluctuations occurs often experience "species shifts" CLIMATE IS A MAJOR FACTOR
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ecological succession
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the orde3rly change in community structure, composition, and dynamics over time. includes both change and devvelopment. can be though of as teh orderly and preofressive replaement of one community by another unil a relatively stable community (climax community) occupies the area.
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three factors used to predict thej outcome of succession in a community
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particular traits of species involved, how the species interact, and the environmental conditions
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successional series or sere
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whole sequence of communities that terminates in a climax community
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seral stage
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intermediate community existing at different points in time
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microseres
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minor successional sequences that occur within the framework of a larger community
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paleoecology
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the study of past relationships of ancient flora and fauna in the environment
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succession is initiated by _____________
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disturbance. with the net result being that the community is forced to change. Such changes can be due to the behavior of species already present in the community (autogenic) or due to outside forces (allogenic.)
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aquatic succession
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th edevelopment of a pond or other aquatic system into a mesic forest.
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eutrophication
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the mineralization of a pond until it builds up and becomes a marsh and eventually a forest.
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terrestrial succession
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the development of a field or new region in to a forest system
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primary succession
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is the establishment of a community where none previously existed, or where an area had its soil seriously depleted
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secondary succession
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is the reestablishment of a community where a preexisting community was disturbed in some way
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autotrophic succession
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available energy INCREASES throughout the process
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heterotrophic succession
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availbale energy DECREASES thoughout the process
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eutrophic systems
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are those rich in nutrients
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oligiotrophic systems
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are those with limited nutrients and productivity
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pioneer species
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are the first to inhabit a new area. once established, they form a pioneer community
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pioneer community
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which begins to break down rock to build up soil. fast growing grasses, shrubs, water tolerant trees, trees with intermediate water tolerance, and, finally water intolerant trees then inhabit the area.
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animal species move into an area in parallel with )_________________
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vegetation
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heterotrophic succession
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occurs in communitites involved in decompositions. it is characterized by early dominance of fungi and explainingg how much each stage is dependent upon the previous one
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