range of tolerance
Range of chemical and physical conditions that must be maintained for populations of a particular species to stay alive and grow, develop, and function normally. See law of tolerance.
Subject:
Chapter 4 - Ecosystems: Components, Energy Flow, and Matter Cycling
pyramid of numbers
Diagram representing the number of organisms of a particular type that can be supported at each trophic level from a given input of solar energy at the producer trophic level in a food chain or food web. Compare pyramid of biomass, pyramid of energy flow.
Subject:
pyramid of energy flow
Diagram representing the flow of energy through each trophic level in a food chain or food web. With each energy transfer, only a small part (typically 10%) of the usable energy entering one trophic level is transferred to the organisms at the next trophic level. Compare pyramid of biomass, pyramid of numbers.
Subject:
pyramid of biomass
Diagram representing the biomass, or total dry weight of all living organisms, that can be supported at each trophic level in a food chain or food web. See pyramid of energy flow, pyramid of numbers.
Subject:
protists (protista)
Eukaryotic, mostly single-celled organisms such as diatoms, amoebas, some algae (golden brown and yellow-green), protozoans, and slime molds. Some protists produce their own organic nutrients through photosynthesis. Others are decomposers and some feed on bacteria, other protists, or cells of multicellular organisms.
Subject:
prokaryotic cell
Cell that does not have a distinct nucleus. Other internal parts are also not enclosed by membranes. Compare eukaryotic cell.
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producer
Organism that uses solar energy (green plant) or chemical energy (some bacteria) to manufacture the organic compounds it needs as nutrients from simple inorganic compounds obtained from its environment. Compare consumer, decomposer.
Subject:
primary productivity
See gross primary productivity, net primary productivity.
Subject:
primary consumer
Organism that feeds on all or part of plants (herbivore) or on other producers. Compare detritivore, omnivore, secondary consumer.
Subject:
precipitation
Water in the form of rain, sleet, hail, and snow that falls from the atmosphere onto the land and bodies of water.
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