OpenStax Biology 2e Chapter 46 Ecosystems

analytical model

ecosystem model that is created with mathematical formulas to predict the effects of environmental disturbances on ecosystem structure and dynamics

apex consumer

organism at the top of the food chain

assimilation

biomass consumed and assimilated from the previous trophic level after accounting for the energy lost due to incomplete ingestion of food, energy used for respiration, and energy lost as waste

biogeochemical cycle

cycling of mineral nutrients through ecosystems and through the nonliving world

biomagnification

increasing concentrations of persistent, toxic substances in organisms at each trophic level, from the primary producers to the apex consumers

biomass

total weight, at the time of measurement, of living or previously living organisms in a unit area within a trophic level

chemoautotroph

organism capable of synthesizing its own food using energy from inorganic molecules

conceptual model (also compartment model)

ecosystem model that consists of flow charts that show the interactions of different compartments of the living and nonliving components of the ecosystem

dead zone

area within an ecosystem in lakes and near the mouths of rivers where large areas of ecosystems are depleted of their normal flora and fauna; these zones can be caused by eutrophication, oil spills, dumping of toxic chemicals, and other human activities

detrital food web

type of food web in which the primary consumers consist of decomposers; these are often associated with grazing food webs within the same ecosystem

ecological pyramid (also Eltonian pyramid)

graphical representation of different trophic levels in an ecosystem based of organism numbers, biomass, or energy content

ecosystem

community of living organisms and their interactions with their abiotic environment

ecosystem dynamics

study of the changes in ecosystem structure caused by changes in the environment or internal forces

eutrophication

process whereby nutrient runoff causes the excess growth of microorganisms, depleting dissolved oxygen levels and killing ecosystem fauna

fallout

direct deposit of solid minerals on land or in the ocean from the atmosphere

food chain

linear representation of a chain of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics

food web

graphic representation of a holistic, nonlinear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics

grazing food web

type of food web in which the primary producers are either plants on land or phytoplankton in the water; often associated with a detrital food web within the same ecosystem

gross primary productivity

rate at which photosynthetic primary producers incorporate energy from the sun

holistic ecosystem model

study that attempts to quantify the composition, interactions, and dynamics of entire ecosystems; often limited by economic and logistical difficulties, depending on the ecosystem

hydrosphere

area of the Earth where water movement and storage occurs

microcosm

re-creation of natural ecosystems entirely in a laboratory environment to be used for experiments

net consumer productivity

energy content available to the organisms of the next trophic level

net primary productivity

energy that remains in the primary producers after accounting for the organisms' respiration and heat loss

net production efficiency (NPE)

measure of the ability of a trophic level to convert the energy it receives from the previous trophic level into biomass

primary consumer

trophic level that obtains its energy from the primary producers of an ecosystem

primary producer

trophic level that obtains its energy from sunlight, inorganic chemicals, or dead and/or decaying organic material

residence time

measure of the average time an individual water molecule stays in a particular reservoir

resilience (ecological)

speed at which an ecosystem recovers equilibrium after being disturbed

resistance (ecological)

ability of an ecosystem to remain at equilibrium in spite of disturbances

secondary consumer

usually a carnivore that eats primary consumers

simulation model

ecosystem model that is created with computer programs to holistically model ecosystems and to predict the effects of environmental disturbances on ecosystem structure and dynamics

subduction

movement of one tectonic plate beneath another

tertiary consumer

carnivore that eats other carnivores

trophic level

position of a species or group of species in a food chain or a food web

trophic level transfer efficiency (TLTE)

energy transfer efficiency between two successive trophic levels