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67 Cards in this Set
- Front
- Back
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Describe the “balance of nature” view of ecological systems
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Idea that natural systems tend towards a steady state, where inputs equal outputs. Dynamic equilibrium. This steady state is seldom attained.
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Distinguish between positive and negative feedback, and provide examples of each
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Positive feedback occurs when an increase in output leads to increase in output. Examples are fire starting in the woods, or introducing a wolf population to a park
Negative feedback is an increase in output leads to later decrease in output. Body temperature is an example. Tend to be more stabilizing and self-regulating. |
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Identify examples of open vs. closed systems, inputs, and outputs
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Open system – some energy or material moves into or out of the system. The ocean is an open system in regard to water because water moves in/out of ocean in association with atmosphere
Closed system – no transfers of energy or material. Earth is materially closed system. |
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Interpret a graph of carrying capacity, overshoot, and collapse, and identify where the population growth rate is exponential
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Carrying capacity starts out being much higher than population, but if population grows exponentially, it will overshoot carrying capacity, ultimately results in collapse of population to lower level. Lag time is period of exponential growth before it exceeds carrying capacity
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Recognize environmental unity vs. uniformitarianism
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Environmental unity holds that everything affects everything else, emphasizes linkages among parts of systems
Uniformitarianism can help predict future environmental conditions based on past/present. Present is key to the past, and past is key to the future. |
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Identify 5 key properties in population dynamics (abundance, birth rate, death rate, growth rate, age structure)
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Birth rate – rate at which births occur in a population, measured either as the nuber of individuals born per unit of time or percentage of births per unit of time compared with total population
Abundance – size of population Death rate – Same as birth rate, just with deaths Growth rate – net increase in some factor per unit time. In ecology, the growth rate of a population, sometimes measured as the increase in numbers of individuals or biomass per unit time and sometimes as a percentage increase in numbers Age structure – population divided into groups by age. Sometimes groups represent actual number of each age in poplation. Sometimes groups represent proportion of population of each age. |
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What did Thomas Malthus contribute to thinking about populations?
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Pointed out that earth cannot maintain an exponentially growing population. Based on three ideals
• Food is necessary for survival • Children will continue to be born Power of population growth is infinitely greater than power of earth to subsistence. |
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Compare primary causes of death in developed vs. developing countries
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o Developed countries experience a greater percentage of chronic illness deaths
o Developing countries have a much more even distribution of death |
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Define zero population growth
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A condition in which the human population, on average, neither increases nor decreases.
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Interpret demographic charts, and describe how demographic patterns differ in developed vs. developing countries
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o Demographic transitionis a three-stage pattern of birth and death rates that has occurred during process of industrial and economic development. Leads to decline in population growth.
o Decline in death rate is first stage of transition. o In non-industrial countries, birth rates and death rates are high and growth rate is low. With industrialization, death rate drops rapidly, birth rate remains high enter stage 2, which is high growth rate. Stage 3 – birth rate drops toward death rate o Key point – demographic transition will take place only if parents come to believe that a having small family is to their benefit. |
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Discuss historical trends in human population growth, and compare the patterns to those of other species
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In 2nd and 3rd periods of history, human population growth occurred with little relative change to maximum life. Changes were in birth/death rates, population growth rates, age structure, average life expectancy.
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Identify the 4 key cycles within the geologic cycle
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o Geologic cycle is the process responsible for formation and change of earth materials
o Tectonic cycle – involves creation/destruction of earth’s solid outer layer o Hydrologic cycle – is the transfer of water from oceas to the atmosphere to the land back to the oceans. o Rock cycle – numerous processes that produce rock and soil. o Biogeochemical cycle - |
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Identify the “big 6” elements that are fundamental to living organisms
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Carbon, hydrogen, nitrogen, oxygen, sulfur, phosphorus
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Explain the difference between endangered, threatened, and vulnerable species
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o Endangered – any species in danger of extinction throughout all or a significant portion of its range
o Threatened – any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range o Vulnerable – threatened to become endangered unless circumstances improve |
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Identify at least three reasons why our society protects endangered species
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o Utilitarian justification – many species prove useful to us
o Ecological justification – organisms necessary to maintain functions of ecosystem o Aesthetic Justification – biological diversity enhances quality of our lives by providing beautiful/appealing aspects of our existence o Moral justification – species have a right to exist o Cultural justification – certain species are important to certain indigenous people |
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Describe four major causes of species declines and extinctions
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o Population risk – random variations in population rates
o Environmental risk – variation in physical or biological environment o Natural catastrophe – sudden change in environment that is not caused by human action o Genetic risk – detrimental change in genetic characteristics |
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Distinguish between tangible and intangible factors in environmental economics
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Tangible – one you can touch, buy, sell. A house lost in a mudslide is an example
Intangible – you can’t touch directly, but you value it |
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Provide examples of “public-service functions” of nature
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o Atmosphere acting as a large disposal site for toxic gases
o Bacteria clean water in soil by decomposing toxic chemicals o pollinators |
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Describe the “tragedy of the commons”
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When a resource is shared, an individual’s personal share of profit from exploitation is usally greater than his or her share of resulting loss
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Identify externalities (indirect costs)
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o Also called indirect cost
o Not recognized by producers as part of their costs and benefits, and therefore not normally accounted for in their cost-revenue analyses |
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Consider how differences in future vs. present value might affect environmental decisions
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Don’t value future environment less than present one
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Distinguish among key components of species diversity: richness, evenness, and dominance
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o Species Richness – total number of species in an area
o Species Evenness – relative abundance of species o Dominant – most abundant species |
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Give an estimated range of the number of species on earth, and discuss why estimates vary
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o Almost 3 million. 1.5 named.
o No one knows because new species are discovered all the time, especially in little-explored areas |
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Explain the major points of biological evolution, and provide examples of natural selection and artificial selection
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Evolution – change in inherited characteristics of a population from generation to generation, distinguishes life from other things in the universe.
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Identify 3 major types of ecological interactions, and describe them in terms of the positive or negative effects for the interactors
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o Symbiosis – relationship between two organisms that is beneficial to both and enhances each organism’s chances of persisting
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Compare fundamental and realized niches
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o Fundamental niche is the role a species can play in the environment
o Realized niche is the role the species actually plays and the role it must carry our in real life. |
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Identify at least 4 ways in which agroecosystems generally differ from natural ecosystems
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o Ecological succession is halted to keep agroecosystem in early successional state
o Biological diversity and food chains are simplified o Crops and plants are in neat rows and fields o Include genetically modified crops |
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Describe why and how people starve
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o People starve in 2 ways
o Undernourishment – results from insufficient calories in available food, dies from lack of energy o Malnourishment – results from the lack of specific chemical components of food such as proteins or vitamins |
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Describe the importance of limiting factors in soil
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o If limiting factor can be improved, then soil will be more productive.
o Liebig’s law of minimum – growth of plant affected by one limiting factor at a time – whose availability is the least in comparison to needs of plant |
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What are different approaches to controlling agricultural pests (usually insects)?
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o Broad-spectrum inorganic toxins
o Petroleum based sprays and natural plant chemicals o Artificial organic compounds o Intergrated pest management o Biological control |
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• Identify three key technological approaches to agriculture, and describe how those approaches might lead to future changes in agriculture
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o Modern mechanized agriculture – production based on highly mechanized technology that has a high demand for resources and makes little use of biologically-based technologies. Determined by economic demand and limited by that demand
o Resource based –agriculture based on biological technology and conservation of land, water, energy. Production is limited by environmental sustainability and availability of resources. Economic demand usually exceeds production o Genetic engineering |
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Discuss conflicting goals for the use of forests
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o Should forest be used only as a resource to provide materials for people and civilizations
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Consider where forests rank in the context of global land uses
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o Beginning of 21st century, 26% of earth’s surface was forested . 3.8 billion hectares, was 3.4 in 1990 but 4 in 1980
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How does forest use differ between developed and developing countries?
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o Developed countries account for 70% of worlds total production and consumption of industrial wood products
o Developing countries produce and consume about 90% of wood used as firewood |
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Describe some ecological functions and ecosystem services provided by forests
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o Evaporating water, slowing erosion, providing habitat for life.
o Influencing amount of light reflected/absorbed. Vegetation warms earth. o Increasing amount of water transpired and evaporated from surface to atmosphere o Greenhouse gas rate release into atmosphere o Changing “surface roughness” which affects wind speed at the surface |
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What are some key impacts of clearcutting?
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o Clearcutting is the cutting of all trees in a stand at the same time.
o Increases erosion, water runoff patterns changed dramatically, exposed soil decayed more rapidly, changes chemical cycling, ground becomes warmer |
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Describe key causes of deforestation
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o Clear land for agriculture and settlement
o To use or sell timber o Indirect – death of trees from pollution or disease |
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Compare the differences between parks and nature preserves or wilderness
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o Park is an area set aside for use by people
o Nature preserve has its primary purpose the conservation of some resource o Park has definite boundaries |
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Discuss the difficulties of applying the “maximum sustainable yield” approach to fisheries and wildlife management
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o The slightest overestimate in carrying capacity would lead to overharvesting, a decline in production, and decline in abundance of the species.
o Impossible to maintain wildlife population o Carrying capacity rarely determined by scientific methods and it varies with environmental changes |
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How is fresh water used, and what are some methods by which people obtain more of it during shortage or drought conditions?
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o Water is used in very high quantities, 1000 times production minerals. Inexpensive resource where abundant.
o Withdrawal of surface water far exceeded withdrawal of groundwater o Major uses of water were for irrigation and thermoelectric industry o Use for irrigation by agriculture increased about 68% |
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Describe how water supply and agriculture are linked
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o Agriculture is biggest water user.
o Price agriculture water to encourage conservation o Use lined or covered canals o Use computer monitoring o Improve irrigation |
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Identify 3 ways that water can be conserved in agriculture, and 3 ways that it can be conserved in households
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Households – more efficient bathroom fixtures, flush only when really necessary, fix leaks quickly, take long bath or long shower.
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• Identify 5 key ecosystem services provided by wetlands
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o Freshwater wetlands are natural sponge for water
o Freshwater wetlands important as areas of groundwater recharge/discharge o Primary nursery grounds for fish, shellfish, o Natural filters that help purify water; plants in wetlands trap sediment and toxins o Coastal wetlands buffer inland areas from storms and high waves |
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What are some environmental impacts of dams?
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o Loss of land, cultural resources, biological resources in reservoir area
o Potential serious flood hazard o Storage of sediment behind dam that would otherwise move downstream o Fragmentation of ecosystems below/above dam o Restricted movement upstream |
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Describe cities as systems—what are key inputs and outputs?
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o City takes in raw materials from surrounding countryside like food, water, wood, energy, mineral ores
o City produces material goods, also export waste to countryside |
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Identify at least 2 issues in urban stormwater management
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During times of rain, flooding can occur due to fact only sewage drains are in cities, causing sewage to be released downstream without treatment
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Characterize the city as a habitat
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o Great deal of unnoticed wildlife
o Urban areas can be modified to provide habitats for wildlife • Species that cannot persist in an urban environment and disappear • Those that tolerate an urban environment but do better elsewhere • Those that have adapted to urban environments and are abundant • ******* pests Cities are a habitat, albeit artificial. Provide all needs like physical structures and necessary resources such as food, minerals, and water. Cities have natural habitats like parks and preserves. Cities that are seaports often have many species of marine wildlife |
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Sustainability
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Management of all natural resources and the environment with goals of allowing the resources to remain at or above some specialized level, and ecosystem to retain its functions.
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Community
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Group of populations of different species living in same area and interacting with one another. Living portion of the ecosystem.
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Ecosystem
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Ecological community and its local, nonbiological community
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Trophic level
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In ecosystem, all organisms that are same number of food chain steps from primary source of energy
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Ecological Niche
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the general concept that niche is species' profession
What it does to make a living. Term is also used to refer to a set of environmental conditions with which a species is able to persist |
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Biome
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kind of ecosystem. Rain forest is an example of a biome.
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Competitive Exclusion Principle
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Idea that 2 populations of different species w/ exactly same requirements cannot persist indefinitely in same habitat. One will always win while other becomes extinct.
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Biodiversity
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1) genetic diversity - total # of genetic characteristics
2) species diversity 3) habitat/ecosystem and diversity - number of kinds of habitats and ecosystems in unit area. |
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Carrying capacity
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Maximum abundance of a population or species that can be maintained by habitat or ecosystem without degrading the ability of an ecosystem to maintain that abundance in the future
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Limiting Factor
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The single requirement for growth available in the least supply in comparison to need of an organism. Originally applied to crops but now applied to all species.
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Theory vs Scientific Theory
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Theory - a guess or an idea without base or proof
Scientific Theory - a grand scheme that relates and explains many observations and is supported by a great deal of evidence |
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Keystone Species
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A species, such as sea otter, that has a large effect on its community or ecosystem so that its removal or addition to community leads to major changes in abundances of many species
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Facilitation
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During succession, one species prepares the way for the next, and may be necessary for their occurrence)
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Interference
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When during succession, one species prevents entrance of later-successional species into an ecosystem. When grass grows too dense and other species can't get in
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Risk-Benefit analysis
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In environmental economics, weighing the riskiness of the future against the value we place on things in present
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Aquaculture
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production of food from an aquatic habitat
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Minimum viable population
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minimum number of individuals that have a chance of persisting for a specific time period
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Species
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group of individuals capable of interbreeding
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Biogeochemical Cycle
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cycling of chemical elements through biosphere, its pathways, storage locations, and chemical forms in living things, the atmosphere, oceans, sediments, lithosphere
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Precautionary Principle
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idea that even with scientific uncertainty and unable to prove cause and effect, we should still take cost-effective precautions to solve environmental problems when there appears to be a threat of potential serious and irreversible environmental damage.
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