Chapter 13: The Principles of Ecology Study Guide

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ecology
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the study of interactions among living things, and between living things and their surroundings
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levels of organization
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organism –> population –> community –> ecosystem –> biome
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observation
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the act of carefully watching something over time, key part of a scientist’s toolkit because most environmental changes happen over a long peroid of time, monitor populations through direct (species that are easy to follow) and indirect (species difficult to track) surveys. examples: quadrat sampling, mark and recapture
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experimentation
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performing experiments in the lab or in the field, lab experiments gives the researcher more control however the artificial setting does not reflect the complex interactions that occur in nature, field experiments allow scientists to interact with organisms in a natural setting
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modeling
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scientists use computer and mathematical models to describe and model nature, can manipulate different model variables to learn about organisms or whole ecosystems
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biotic factors
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living things, i.e. plants, animals, fungi, bacteria
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abiotic factors
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nonliving things, i.e. moisture, temperature, wind, sunlight and soil
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biodiversity
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the assortment of living things in an ecosystem
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keystone species
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a species that has an unusually large effect on its ecosystem, i.e. by constructing dams, beavers create an ecosystem used by a wide variety of species
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producers
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organisms that get their energy from nonliving resources (autotrophs)
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consumers
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organisms that get their energy by eating other living or once-living resources, such as plants and animals (heterotrophs)
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chemosynthesis
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the 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 sequence that links species by their feeding relationships
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herbivores
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organisms that only munch on plants
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carnivores
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organisms that love their meat
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omnivores
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organisms that are chill with meat and plants
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detritivores
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organisms that eat dead organic matter
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decomposers
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detritivores that break down organic matter into simpler compounds
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specialist
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consumer that primarily eats on specific organism, i.e. the Florida snail kite only eats apple snails
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generalist
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consumers that have a varying diet, i.e. the wolf likes to eat elk, moose, dear, beavers AND mice
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trophic levels
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the levels of nourishment in a food chain, producers –> primary consumers —> secondary consumers —> tertiary consumers
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food web
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a 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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the circular pathway of water on Earth from the atmosphere, to the surface, below ground and back (evaporation/transpiration, condensation, precipitation, runoff, groundwater/seepage)
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biogeochemical cycle
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the movement of a particular chemical through the biological and geological parts of an ecosystem (there are 4 main ones)
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oxygen cycle
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the movement of oxygen throughout an ecosystem as a byproduct of photosynthesis,then taken in by organisms and released as carbon dioxide through respiration and cycles back
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carbon cycle
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the transfer of carbon between plants and animals, plants use energy from the sun to convert carbon dioxide from the air into organic matter that becomes a part of the plant’s structure, the carbon then moves through the biotic world as one organism eats another
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nitrogen cycle
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occurs mostly underground, where bacteria transform ammonium into nitrates, which are used by plants to make amino acids
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nitrogen fixation
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the conversion of gaseous nitrogen into ammonia
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phosphorus cycle
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Cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment
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biomass
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a measure of the total dry mass of organisms in a given area
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energy pyramid
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a diagram that compares energy used by producers, primary consumers and other trophic levels, illustrates how availdable energy is distributed among trophic levels in an ecosystem
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biomass pyramid
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diagram that compares the biomass of different trophic levels within an ecosystem, provides a picture of the mass of producers needed to support primary consumers, the mass of primary consumers required to support secondary consumers and so on
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pyramid of numbers
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shows the number of individual organisms at each trophic level in an ecosystem

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