OFL Biology Unit 7 – Flashcards
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Producer
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organisms that get their energy from nonliving resources and make their own food; a.k.a. autotrophs. They provide the energy in an ecosystem. Most producers use sunlight
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heterotrophs
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consumers. organisms that get their energy by eating other living or once-living resources
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chemosynthesis
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process by which an organism forms carbohydrates using chemicals, rather than light, as an energy source
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food chain
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a single sequence that links species by their feeding relationships
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decomposers
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organisms that eat dead organic matter and break it down into simpler compounds. They are important in an ecosystem because they return important nutrients back into the environment
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food webs
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model that shows the complex network of feeding relationships and the flow of energy within and sometimes beyond an ecosystem.
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hydrologic cycle
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water cycle; circular pathway of water on Earth from the atmosphere, to the surface, below the ground, and back.
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similarity between oxygen cycle and carbon cycle
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cycles that depend on photosynthesis
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carbon cycle
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the circular pathway of carbon flowing from the environment to living organisms and back again.
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nitrogen fixation
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process in which certain types of bacteria convert gaseous nitrogen into ammonia
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primary consumers
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herbivores; first consumer above the producer trophic level
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secondary consumer
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carnivores that eat herbivores
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trophic level
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levels of nourishment in a food chain; carnivores are at the highest level, herbivores are at the second level, producers are at the bottom first level.
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Energy pyramid
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diagram that compares energy used by producers, primary consumers, and other trophic levels. the pyramid shows how available energy is distributed among trophic levels; energy levels on the bottom is largest, and energy is progressively lost as it moves up the pyramid
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competitive exclusion
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competition of two species competing for the same resources; one will be pushed into another ecological niche, die out, or experience divergent evolution
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ecological equivalents
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species that occupy similar ecological niches but live in different geographical regions
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predation
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process by which one organism captures and feeds upon another organism
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commensalism
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a symbiotic relationship in which one organism receives an ecological benefit from another organism that neither benefits nor is harmed from the relationship.
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parasitism
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relationship in which one organism benefits while the other is harmed; the host is kept alive for days or years
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survivorship curve
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generalized diagram showing the number of surviving members over time from a measured set of births; gives information about the life history of a species
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immigration
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movement of individuals into population from another population
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carrying capacity
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the maximum number of individuals of a particular species that the environment can normally and consistently support; changes in the environment can lead to changes in the carrying capacity
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density-dependent limiting factor
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limiting factors that are affected by the number of individuals in a given area; competition, predation, parasitism, and disease are DDLF
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density-independent limiting factor
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factor in the environment that limit a population's growth regardless of the density of the population
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pioneer species
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the first organisms that live in a previously uninhabited area; typical examples are lichens and some mosses
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secondary succession
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reestablishment of a damaged ecosystem in an area where the soil was left intact
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population density
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measurement of the number of individuals living in a given space. Population density=number of individuals/area of the space
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uniform dispersion
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species will live at specific distances from one another due to territoriality and competition for limited resources
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factors that affect population size
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immigration, births, emigration, deaths
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exponential growth
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type of growth in population that occurs when a population size increases dramatically over a period of time
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logistical grwoth
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a population begins with a period of slow growth followed by a brief period of exponential growth before leveling off at a stable size
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mutualism
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interspecies interaction in which both organisms benefit from one another
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