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54 Cards in this Set
- Front
- Back
What term defines a group of different species that occupy a given area, interacting either directly or indirectly?
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community
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What term describes the count of the number of species occurring within a community, represented by the symbol (S)?
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species richness
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What represents the percentage each species contributes to the total number of individuals of all species?
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relative abundance
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What depends on the number of species as well as relative abundance?
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species diversity
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What is species richness?
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number of species in a community
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What term describes how close in numbers the different species in an environment are (relative abundance)?
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species evenness
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What provide a way to quantify the relationship between species number and relative abundance?
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diversity indexes
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In reference to the Shannon-Weiner Index, when there is an absence of diversity and only one species is present, what does H equal?
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0
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When a single or few species predominate within a community, these species are referred to as __________.
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dominants
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What is the converse of diversity?
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dominance
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Which species has a disproportionate impact on the community relative to its abundance?
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keystone species
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What would occur if a keystone species was removed from a community?
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changes in community structure
significant loss of diversity |
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How are the form and structure of terrestrial ecosystems primarily defined?
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by their vegetation
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How are the physical structures of aquatic communities primarily defined?
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features of the abiotic environment (e.g. salinity, water depth)
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What is the upper layer of the forest, which is primary site of energy fixation through photosynthesis?
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canopy
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Which layer of the forest is situated underneath the canopy and will only form if enough sunlight reaches the lower layers?
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understory
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Which layer of the forest depends on various abiotic conditions (e.g. soil, moisture) and density of the canopy and understory?
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herb layer
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Which layer of the forest is where decomposition takes place and nutrients and minerals are recycled?
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forest floor
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How is the vertical structure of terrestrial environments determined?
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by the growth form of plants
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How is the vertical structure of aquatic environments determined?
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by light penetration through the water column
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Which zone of water is where the availability of light supports photosynthesis?
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photic zone
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Which zone of water is an area without light?
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aphotic zone
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Which zone of water is where decomposition is most active?
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benthic zone
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What term describes the changes in the physical and biological structures of communities as one moves across the landscape?
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zonation
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__________ is spatial change in community structure.
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Zonation
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What term describes the differences in environmental conditions from one area to the next?
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environmental heterogeneity
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Environmental heterogeneity influences ________ _________.
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community diversity
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Who was the first to quantify the relationship between structural heterogeneity of vegetation and diversity of animals?
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Robert MacArthur
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What term encompasses the idea that the niche is the role a species plays in a community?
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Eltonian niche
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What is the term that describes a group of organisms (usually animals) that all "make their living" in the same way or exploit a common resource in a similar fashion?
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guild
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What are some examples of a guild?
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seed-eating organisms in a desert
fruit-eating birds in a tropical rainforest |
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What is the term used for plants, which is a combination of structure and growth dynamics?
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life-form
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What is a descriptive diagram that represents the flow of energy from prey (the consumed) to predator (the consumer)?
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food chain
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What are highly interwoven diagrams with linkages representing a wide variety of species interactions?
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food webs
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In a food chain, how do arrows flow?
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Arrows flow from prey (consumed) to predator (consumer).
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What is the term that describes the arrows from one species to another that indicate the consumed and the consumer?
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links
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Which species feed on no other species but are fed upon by others?
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basal species
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Which species feed on other species, and they themselves are prey of other species?
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intermediate species
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Which species prey on intermediate and basal species?
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top predators
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What is a trophic level?
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position in a food web
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How do ecologists often simplify species into broader categories that represent general feeding groups based on the source of which they derive energy?
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trophic levels
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What is the trophic level of primary producers?
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autotrophs
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What is the trophic level of herbivores, carnivores, and omnivores?
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heterotrophs
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What is the first trophic level?
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primary producers (autotrophs)
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What is the second trophic level?
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primary consumers
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What is the third trophic level?
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secondary consumers
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What is the fourth trophic level?
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tertiary consumers
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What occur when one species does not interact with a second species directly, but instead influences a third species that does directly interact with the second?
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indirect interactions
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What is the indirect interaction where the predator enhances one or more inferior competitors by reducing the abundance of the superior competitors?
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keystone predation
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Name the term.
influence of chemical and physical factors on ecosystems the structure of food chains and food webs is controlled (limited) by the productivity and abundance of populations in the trophic level below |
bottom-up control
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Name the term.
influence on consumers on ecosystems the predator populations control the abundance of prey species, and the prey of the prey, and so on |
top-down control
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Name the term.
may involve indirect interactions linked through intermediary species effects of predators on prey--alterations in abundance, biomass, or productivity can be top-down or bottom-up |
trophic cascade
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What describes the scenario in which the food chain/food web is disrupted by the removal of a top predator, or a third or fourth level consumer?
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top-down cascade
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What describes the scenario in which a primary producer, or primary consumer is removed, and there is a diminishment of population size throughout the community?
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bottom-up cascade
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