Unit 9 (Ecology) Test

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population
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A group of individuals that belong to the same species and live in the same area
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population density
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Number of individuals per unit area
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exponential growth
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Growth pattern in which the individuals in a population reproduce at a constant rate due to ideal conditions and unlimited resources (J shape)
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limiting factors
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Anything that limits (restricts) the size of a population
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logistic growth
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A model describing population growth that levels off as population size approaches carrying capacity (S shape)
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carrying capacity
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Largest number of individuals of a population that a environment can support
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density-dependent factors
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limiting factors only when a population reaches a certain density. ex) disease
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density-independent factors
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limiting factor that affects all populations in similar ways, regardless of population size. ex) weather related events
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death rate
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The number of deaths in a population in a certain amount of time
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birth rate
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The number of births in a population in a certain amount of time
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boom-and-bust cycles
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Populations repeatedly overshoot the carrying capacity of their habitat and crash catastrophically ex) hare and lynx
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community
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(ecology) a group of interdependent organisms inhabiting the same region and interacting with each other
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biodiversity
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Number and variety of species in a given area
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disturbance
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An abiotic event that kills or damages some organisms and thereby creates opportunities for other organisms to grow and reproduce.
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trophic structure
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The feeding relationships between organisms.
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competition
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Interaction in which two or more species use the same limited resource
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competitive exclusion principle
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Ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time
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niche
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the specific role of an organism in its environment. The sum total of how it uses its abiotic and biotic resources.
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predation
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An interaction in which one organism captures and feeds on another organism
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predator
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An animal that hunts other animals for food
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prey
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An animal that is hunted for food
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keystone species
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A species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche.
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symbiotic relationship
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close association between two organisms
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commensalism
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A relationship between two organisms of different species where one benefits and the other is neither harmed nor benefited
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mutualism
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A relationship between two species in which both species benefit
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parasitism
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A relationship between two organisms of different species where one benefits and the other is harmed
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ecological succession
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Gradual change in living communities that follows a disturbance
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primary succession
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Succession that occurs on surfaces where no soil or life exists
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secondary succession
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Succession following a disturbance that destroys a community without destroying the soil
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ecosystem
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A community of organisms and their abiotic enviornment.
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energy flow
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One-way movement of energy up the trophic levels in an ecosystem.
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chemical cycling
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The use and reuse of chemical elements within an ecosystem. (carbon, nitrogen, phosphorus…)
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food chain
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A series of steps in which organisms transfer energy by eating and being eaten
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producers
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An organism that can make its own food
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primary consumers
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An organism that eats producers
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secondary consumers
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Carnivores that eat herbivores.
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tertiary consumers
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Carnivores that eat other carnivores
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quaternary consumers
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consumers that consume tertiary consumers (killer whale).
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detritovore
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Organisms that eat dead and decaying organic matter
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decomposition
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A chemical reaction that breaks down compounds into simpler products
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food web
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a complex diagram representing the many energy pathways in a real ecosystem
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water cycle
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Cycle of water through the atmosphere and biosphere. (precipitation and evaporation over the sea -> moves over land -> precipitation over land -> surface and ground water -> flow to sea) (evaporation and transpiration on land)
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evaporation
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water vapor to liquid water
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transpiration
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water moving up and exiting plant xylem through adhesion and cohesion.
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condensation
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The change from water vapor to liquid water
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precipitation
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Any form of water that falls from the clouds
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carbon cycle
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Cycle of carbon in the atmosphere and biosphere. (CO₂ -> photosynthesis/ plants -> primary consumers -> higher consumers -> cellular respiration -> CO₂) (CO₂ -> photosynthesis/ plants -> detritus/ decomposition -> CO₂) (wood and fossil fuels -> CO₂)
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nitrogen cycle
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Cycle of nitrogen through the atmosphere and biosphere. (N₂ -> nitrogen fixation in legume root nodules -> NH₄⁺ -> nitrification -> NO₃⁻ -> N₂ or plants -> animals -> detritus and decomposition -> NH₄⁺)
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nitrogen fixation
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bacteria convert N₂ to ammonium (NH₄⁺).
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nitrification
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bacteria convert ammonium (NH₄⁺) to nitrate (NO₃⁻).
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denitrification
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bacteria convert nitrate back to nitrogen gas (N₂)
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nitrate
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NO₃⁻. Nitrified form of nitrogen from NH₄⁺ that is usable by plants.
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ammonium
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NH₄⁺. Nitrogen-fixed form of nitrogen that is usable by plants
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phosphorus cycle
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Cyclic movement of phosphorus in different chemical forms from environment to organisms to the environment again. (rock -> inorganic soil -> plants -> animals ->soil -> water -> precipitated soil form -> rock -> uplifting)
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weathering
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Breaking down of rocks
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biological magnification
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Increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain
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global warming
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An increase in average temperature of the Earth’s atmosphere.
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ecology
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Study of how organisms interact with each other and with their environment
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abiotic factor
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nonliving parts of an ecosystem
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biotic factor
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living parts of an ecosystem
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biosphere
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Composed of all living organisms on Earth.
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10% rule
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90% of the energy in one topic level is lost before it reaches the next level.
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invasive specie
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specie immigrated to an environment it is not native to and has no natural predators.
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movement of energy
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flows THRU an ecosystem. Much is lost as heat.
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movement of matter
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cycles within an ecosystem in different forms. Never lost.

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