Term
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Definition
consists of all the organisms in a community as well as all the abiotic factors with which they interact
-range from a microcosm such as an aquarium to a large area such as a lake or forest |
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Term
| Ecosystem ecology emphasizes |
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Definition
| energy flow and chemical cycling |
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Term
| Ecosystem ecologists view ecosystems as |
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Definition
transformers of energy and processors of matter
-this view de-emphasizes the particular species in an ecosystem in favor of studying nutrient cycles and energy flows |
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Term
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Definition
-energy flows through an ecosystem
-nutrients cycle within an ecosystem |
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Term
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Definition
-Is the percentage of production transferred from
one trophic level to the next
-Usually ranges from 5% to 20% |
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Term
| Secondary production of an ecosystem |
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Definition
| amount of chemical energy in consumers’ food that is converted to their own new biomass during a given period of time |
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Definition
| show a sharp decrease at successively higher trophic levels |
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Term
| Certain aquatic ecosystems have |
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Definition
| inverted biomass pyramids |
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Term
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Definition
| Represents the number of individual organisms in each trophic level |
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Term
| The dynamics of energy flow through ecosystems |
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Definition
| have important implications for the human population |
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Term
| A relatively inefficient way of tapping photosynthetic production |
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Definition
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Term
| Most terrestrial ecosystems |
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Definition
| Have large standing crops of primary producers despite the large numbers of herbivores |
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Term
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Definition
proposes factors that keep herbivores in check:
-Plants have defenses against herbivores
-Nutrients, not energy supply, usually limit herbivores
-Abiotic factors limit herbivores
-Competition and Predator-prey interactions check herbivore densities |
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Term
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Definition
| Biological and geochemical processes that move nutrients between organic and inorganic parts of the ecosystem |
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Term
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Definition
the recycling of essential chemical elements
-Includes the main reservoirs of elements and the processes that transfer elements between reservoirs |
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Term
| Nutrient circuits that cycle matter through an ecosystem |
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Definition
| Involve both biotic and abiotic components and are often called biogeochemical cycles |
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Term
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Definition
mostly bacteria and fungi that are essential components of nutrient cycles
-decompose organic material and return elements to inorganic reservoirs |
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Term
| Gross Primary Production(GPP) |
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Definition
| equivalent to total photosynthesis or carbon fixation in an ecosystem |
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Term
| Net Primary production(NPP) |
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Definition
equal to GPP minus the energy used by the primary producers for respiration
-only available to consumers |
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Term
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Definition
-Dominated by open ocean
-Most productive acquatic biomes are estuaries, reefs, and algal beds |
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Term
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Definition
| Climate has a great impact on the distribution of organisms, and on productivity |
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Term
| Actual evapotranspiration |
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Definition
the amount of water annually transpired by plants and evaporated from a landscape
-Is related to net primary production |
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Term
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Definition
-Contribute about two-thirds of global NPP and marine ecosystems about one-third
-Much of the ocean is as unproductive as the Sahara Desert |
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Term
| Experiments in an ocean region showed that iron |
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Definition
| limited primary production |
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Term
| Hubbard Brook Experimental Forest |
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Definition
-research team constructed a dam on the site to monitor water and mineral loss
-In one experiment, the trees in one valley were cut down and the valley was sprayed with herbicides
-Net losses of water and minerals were studied and found to be greater than in an undisturbed area
-These results showed how human activity can affect ecosystems |
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Term
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Definition
-The human population is disrupting chemical cycles throughout the biosphere
-About 1/3rd of nitrogen fixation is by humans (for fertilizers, etc.)
-Carbon emissions causing increase in atmospheric C02 concentrations
-As the human population has grown in size our activities have disrupted the trophic structure, energy flow, and chemical cycling of ecosystems in most parts of the world |
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Term
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Definition
The addition oflarge amounts of nutrients to aquatic ecosystems such as lakes and near-shore oceans
-Has a wide range of ecological impacts including eutrophication |
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Term
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Definition
excessive algal production caused by increased nutrient availability
-This has several effects including loss of light in deeper waters, and loss of dissolved oxygen in water due to respiration by alga and decomposers.
-Anoxic conditions kill fish and other aquatic life |
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Term
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Definition
| has caused eutrophication of lakes which can lead to the eventual loss of most fish species from lakes |
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Term
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Definition
caused by combustion of fossil fuels which release sulfur
-North American and European ecosystems downwind from industrial regions have been damaged by rain and snow containing nitric and sulfuric acid |
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Term
| Toxins in the Environment |
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Definition
Humans release an immense variety of toxic chemicals including thousands of synthetics previously unknown to nature
-One of the reasons such toxins are so harmful is that they become more concentrated in successive trophic levels of a food web |
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Term
| In Biological magnification |
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Definition
| Toxins concentrate at higher trophic levels because at these levels biomass tends to be lower |
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Term
| Atmospheric Carbon Dioxide |
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Definition
Due to the increased burning of fossil fuels and other human activities the concentration of atmospheric CO2 has
been steadily increasing |
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Term
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Definition
| testing how elevated CO2 Influences tree growth, carbon concentration in soils, and other factors over a ten-year period |
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Term
| Green House Effect an Global Warming |
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Definition
The greenhouse effect is caused by atmospheric CO2 but is necessary to keep the surface of the Earth at a habitable temperature
-Increased levels of atmospheric CO2 are magnifying the greenhouse effect causing global warming |
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Term
| Depletion of Atmospheric Ozone |
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Definition
Life on Earth is protected from the damaging effects of UV radiation by a protective layer or ozone molecules present in the atmosphere
-destruction of atmospheric ozone probably results from chlorine-releasing pollutants produced by human activity |
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Term
| Scientists first described an ozone hole |
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Definition
| Over Antarctica in 1985; it has increased in size as ozone depletion has increased |
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