Exam 3 Flashcards
What is an ecological community?
A group of interacting species living in a particular area.
What is physical structure defined by?
Species composition, abundance, and spatial distribution.
What factors cause vertical stratification in terrestrial environments?
Light, Moisture, and Temperature
What factors cause vertical stratification in aquatic environments?
Light availability, temperature, and nutrient distribution.
What effect does vertical structure have on diversity?
It increases niche diversity and supports more species.
What are properties of zonation?
Changes in altitude, latitude, tidal level, or distance from shore.
What is species richness?
The number of species
What is species evenness?
Relative abundance of species.
What does a rank abundance curve show?
Species abundance distribution.
What is a keystone species?
Has an extremely disproportionate impact on community structure.
What is a dominant species?
The most abundant species, but not necessarily influential.
What is ecological succession?
Gradual, predictable changes in community composition.
What communities are associated with initial and final stages of succession?
Initial: Pioneer Species
Final: Climax community
What is primary succession?
It starts on a new community.
What is secondary succession?
It starts from a disturbance (eg. forest fire)
What is the discrete succession process?
Discrete suggests distinct stages.
What is the continuum succession process?
Continuum envisions a gradient.
What are the three models used to explain successional changes?
Facilitation, Inhibition, and Tolerance models.
What is heterotrophic succession?
The process by which decomposers break down dead organic matter.
What is plant succession?
The process by which different plant species colonize and replace each other over time.
What is autogenic environmental change?
Changes cause by the community.
What is Allogenic environmental change?
External factors drive change.
How does species diversity change during succession?
Increases initially, stabilizes, may decrease with time.
What is the intermediate disturbance hypothesis?
Intermediate levels of disturbance are necessary to maintain high levels of species diversity in ecosystems.
What is a landscape?
Heterogeneous area composed of interacting ecosystems.
What factors influence dynamics within a habitat patch?
Patch size, shape, and connectivity,
What role does a patch perimeter and area play in patch composition?
They affect the movement and dispersal of organisms, the availability of resources, and the interactions between species.
What are the effects of habitat fragmentation on plants and animals?
Reduced population size, increased edge effects, changes in species compositon, disruption of ecological processes.
How does fragmentation affect animal movement?
It can create movement barriers and change movement patterns.
What is edge affect?
Changes in population or community structures at the boundary of two habitats.
What is an ecotone?
A transitional area between two ecosystems exhibiting characteristics of both.
What is the equilibrium theory of island biogeography?
It explains species richnees on islands considering immigration and extinction rates.
What factors determine the expected number of species on an island?
Immigration and extinction rates.
If given spatial information about two different islands, what determines the relative equilibrium species number of each island?
Larger islands and closer islands typically have more species.
What is a metapopulation?
A population of populations linked by migration.
What factors influence the distribution of a metapopulation among habitat patches?
Habitat quality, patch size, and isolation.
What is an ecosystem?
A biological community and its abiotic environment interacting as a functional unit.
What are ecosystems components?
Biotic and abiotic
Are ecosystems open or closed?
They are open systems that exchange energy and matter with their surroundings.
What are major inputs of ecosystems?
Solar energy and nutrients
What are major outputs of ecosystems?
Heat and Waste
What is primary productivity?
The rate of biomass production by autotrophs.
How do GPP and NPP differ?
GPP is total photosynthesis and NPP is GPP minus respiration.
How do we measure primary production and standing crop biomass?
Satellite data for primary production and biomass sampling for standing crop
What are some of the large-scale trends in productivity in terrestrial and aquatic ecosystems?
Terrestrial productivity tends to decrease with increasing latitude. Aquatic productivity varies with nutrient availability.
What limits productivity in various terrestrial and aquatic ecosystems?
Nutrient availability, temperature, and water availability.
How do producers allocate productivity to biomass?
Plants allocate due to environmental conditions and nutrient availability.
How does biomass allocation vary with age and with plant type?
Young plants allocate more to growth and older plants allocate more to reproduction.
What are the patterns in root-to-shoot ratios and biomass distribution?
Varies among plant species and environmental condition.
What is secondary production?
The generation of biomass by heterotrophic organisms
What are the different ways in which energy is used by secondary producers?
Metabolism, growth, and reproduction.
What is assimilation efficiency?
Proportion of ingested food that is assimilated.
What is production efficency?
Proportion of assimilated energy converted into biomass.
What is consumption efficiency?
Maximizing value of consumption with the least amount of energy used.
How does energy flow through different kinds of ecosystems?
Through trophic levels. (eg. Producers, primary consumers, secondary consumers)
What is trophic transfer efficiency?
The percentage of energy transferred from one trophic level to the next.
What is the 10% rule?
Only 10% of energy is passed from one trophic level to the next, with the rest lost as heat or used for metabolic processes.
How do biomass pyramids differ in various ecosystems?
Biomass pyramids can be upright, inverted, or pyramid-shaped, reflecting variations in energy transfer efficiency and the structure of ecosystems.
What is meant by Human appropriation of NPP?
Human use of earth’s NPP.
What are the major types of decomposer organisms?
Bacteria, fungi, and insects/earthworms
What factors affect rates of decomposition of plant material?
Temperature, moisture, nutrient availability, and the composition of the plant material.
What is immobilization?
The conversion of inorganic nutrients into organic forms by microbes, making them temporarily unavailable.
What is mineralization?
converting organic nutrients into inorganic forms, making them available for plant uptake.
How do plants, bacteria/fungi, and other consumers in soil impact rates of nutrient cycling?
Plants contribute organic material to the soil through litter, bacteria decompose organic matter releasing nutrients, and other consumers can further influence nutrient cycling by excreting waste.
How does nutrient movement differ from energy movement in ecosystems?
Nutrients are recycled within ecosystems, while energy is a one-way flow.
How do nutrient dynamics differ in a tropical forest from a temperate forest?
Nutrient cycling is often more rapid in tropical forests due to higher temperatures and decomposition rates.
How is nutrient cycling in aquatic ecosystems similar to and different from nutrient cycling in terrestrial ecosystems?
Similarities include the basic nutrient cycles, but aquatic ecosystems may have unique processes due to water movement and the absence of some terrestrial features.
What is the river continuum?
Changes in physical and biological characteristics of a river ecosystems along its length.
What is nutrient spiraling?
The cycling of nutrients down stream in a flowing water system.
What are the general pools and fluxes in the global carbon cycle?
Pools include the atmospshere, oceans, soil and living organisms. Fluxes involve processes like photosynthesis, respiration, and decomposition.
What are the major pools and fluxes in the global nitrogen cycle?
Pools: atmosphere, soil, living organisms
Fluxes: nitrogen fixation, nitrification, denitrification.
What is Nitrogen fixation?
Nitrogen gas to ammonia, bacteria responsible
What is nitrogen mineralization?
Organic nitrogen to ammonium; decomposer microbes responsible.
What is nitrogen immobilization?
Ammonium to organic nitrogen; microbes responsible.
What is nitrogen ammonification?
Organic nitrogen to ammonium; decomposers responsible
What is nitrogen nitrification?
ammonium to nitrite; bacteria responsible.
What is nitrogen denitrification?
Nitrate to nitrogen gas; bacteria responsible.
What is leaching?
movement of nutrients through soil often into water bodies.
What are the largest pools and fluxes of the global sulfur cycle?
Pools: oceans, sedimentary rocks, living organisms.
Fluxes: Weathering, volcanic emissions, human activity.
What are the largest pools and fluxes of the global phosphorous cycle?
Pools: sedimentary rocks, oceans, living organisms.
Fluxes: Weathering, erosion, runoff.
How have humans affected these biogeochemical cycles?
Burning fossil fuels, deforestation, and industrial processes have altered these cycles by releasing large amounts of stored nutrients into the environment.
