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81 Cards in this Set
- Front
- Back
of all human activities _______ has proven to be the most sustainable
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agriculture
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What does it mean to "bank" farmers?
(in the US) |
to pay farmers not to grow crops b/c there is enough production
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Name the 2 ways in which people starve
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undernourishment and malnourishment
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Undernourishment
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-results from a lack of sufficient calories in available food
-people eventually die from total lack of energy -manifests itself as obvious, fast-acting, dramatic famines |
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Malnourishment
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-results from the lack of specific chemical components of food, such as proteins, vitamins, or other essential chemical elements
-long term and insidious -ex: kwashiorkor |
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Most of the world's food is provided by only ____ # of crop species, and ____ # of those privide over 80% of the total calories consumed
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14;6
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Name the 3 most vital world crops
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1. wheat
2. rice 3. maize (corn) |
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What is forage?
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crops grown as food for domestic animals
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rangeland
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provides food for grazing animals w/o plowing and planting
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pasture
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plowed, planted, and harvested land that provides food for animals
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aquaculture
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the farming of food in aquatic habitats-both marine and freshwater (ex: carp, shrimp)
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mariculture
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the farming of ocean fish (ex: oysters, mussels)
These farms are grown on rafts in intertidal zones |
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agroecosystems
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ecosystems created by agriculture, typically w/ low genetic, species, and habitat diversity
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In farming, people try to _______ ecological succession, keeping it in an ________ stage
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stop;early
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monoculture
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large areas planted w/ a single species or even a single strain
-makes entire crop v. vulnerable to attack by a single pest, disease, or environmental condition |
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Crop rotation
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(counteracts monoculture)
when different plants are planted in turn in the same field, with the field occasionally left fallow |
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What is Liebig's law of the minimum?
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the idea that some single factor determines the growth and presence of a species
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limiting factor
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the factor whose availability is the least in comparison to the needs of the plant
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macronutrients
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chemical elements required by all living things in relatively large amounts (CHONPS)
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micronutrients
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chemical elements required in small amounts-either in extremely small amounts by all life, or in moderate to small amounts by some life (ex: zinc)
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synergistic effect
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a change in the availability of one resource affects the response of an organism to some other resource
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3 major technological approaches to agriculture
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1. modern mechanized agriculture
2. resource-based agriculture 3. bioengineering |
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Green Revolution
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the name attached to post WWII programs that led to the development of new straings of crops with higher yields, better resistance to disease, and better ability to grow under poor conditions
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organic farming
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farming that is more "natural" in the sense of not using artificial pesticides, and, more recently not using genetically modified crops
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Genetically Modified Crops
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GMCs are crop species modified by genetic engineering to produce higher crop yields and increase resistance to drought, cold, heat, toxins, plant pests, and disease
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Compared to unplowed soil, plowed soil has little _____ ________ and lacks ____ ______
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organic matter; definite layers
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Explain the Dust Bowl phenomenon
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the area had been part of a prairie, where grasses were healthy and protected the soil. When plowed, the soil dried out and high winds caused severe erosion
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Explain the chemical effects of sedimentation on water bodies
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eutrophication! nitrates and other fertilizers are carried down stream, enriching the water environment and promoting TOO MUCH BAD algae growth
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Production of soil is
a. fast b. slow |
b. SLOW
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soil horizons
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the series of layers soils are divided into over time
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soil fertility
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the capacity of soil to supply nutrients necessary for plant growth
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contour plowing
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plowing land along topographic contours, as much in a horizontal plane as possible (perpendicular to the slopes), thereby decreasing the erosion rate
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No-till agriculture
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aka conservation tillage
-combination of farming practices that includes not plowing the land, instead using herbicides to control weeds |
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biological control
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the use of biological predators and parasites to control pests (ex/ ladybugs!)
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integrated pest management
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IPM uses a combination of methods to control agricultural pests, including biological and chemical agents.
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terminator gene
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makes crops sterile.
prevents GMCs from spreading and protects a corporation's market |
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overgrazing
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when the carrying capacity of the land is exceeded; slows the growth of vegetation, reduces plant diversity, leads to dominance of weeds, hastens soil erosion, subject land to trampling
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desertification
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the deterioration of lanf in arid, semi-arid, and dry sub-humid areas due to changes in climate and human activities
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landscape perspective
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the concept that effective management and conservation recognizes that ecosystems, populations, and species are interconnected across large geographic areas
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silviculture
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the professional growing of trees
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public service functions
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functions performed by ecosystems for the betterment of life and human existence (ex: trees cleaning the air)
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Leaves and roots in a tree are connected by 2 transportation systems
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1. phloem
2. xylem |
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phloem
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(outside of living bark)
transports sugars and other organic compounds down to stems and roots |
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xylem
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(inside of livinig bark)
transports water and inorganic molecules upward to the leaves. water is transported by a sun-powered pump (evapotranspiration) |
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each species of tree has its own niche, determined by _______ and _______
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water content of the soil ; forest tolerance of shade
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stand
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an informal term used to refer to a group of trees. they can be small to medium-sized
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2 major kinds of commercial stands
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1. even-aged stands
2. uneven-aged stands |
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even-aged stands
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all live trees begin growth from seeds and roots germinating the same year
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uneven-aged stands
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all the trees ini that area have at least 3 distinct age classes among them
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old-growth forest
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aka virgin forest
a forest that has never been cut |
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second-growth forest
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a forest that has been cut and regrown
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rotation time
(trees) |
the time between cuts of a stand
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dominant trees
codominant intermediate suppressed |
domiant are tallest, most common
codominants are fairly common and share the canopy intermediate form the layer of growth beneath the dominants suppressed grow in the understory |
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site quality
(think industrially) |
the maximum timber crop the site can produce in a given time
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clear-cutting
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the cutting of all trees in a stand at one time
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alternatives to clear cutting
(there are 4) |
selective cutting
shelterwood cutting seed-tree cutting strip-cutting |
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shelterwood-cutting
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cutting dead and less desirable trees first and later cutting mature trees, so that there are always young trees around
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seed-tree cutting
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removes all but a few seed trees to promote regeneration of the forest
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selective cutting
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individual trees are marked and cut ----> thinning
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strip-cutting
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narrow rows of forests are cut, leaving wooded corridors
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plantation
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a stand of a single species planted in straight rows
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sustainable forestry
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a resource can be harvested at a rate that doesn't decrease the ability of the forest ecosystem to continue to provide that same rate of harvest indefinitely
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certification of forestry
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formal process to compare the actual practices of specific corporations or gov't agencies with practices that we believe to be consistent with sustainability
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indirect deforestation
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the loss of forests from pollution or disease
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parks vs. preserves
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parks are set aside for use by people.
preserves may be used by peopl, but is set aside for environmental reasons |
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wilderness
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an area undisturbed by people
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maximum sustainable yield
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the populatin size that yielded maximum production (measured as either a net increase in the number of individuals in the population or as a net change in biomass) that would allow this population to be sustained indefinitely w/o decreasing its ability to provide the same level of production
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minimum viable population
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the estimated smallest population that can maintain itself and its genetic variability indefinitely
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logistic carrying capacity
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carrying capcity as defined by the logistic growth curve
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optimum sustainable population
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the maximum population that can be sustained indefinitely w/o decreasing the ability of that species to sustain that population level for some specified time
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in the logistic growth curve, the greatest production occurs when the population is exactly ______ of the carrying capacity
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1/2
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time series
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a set of estimates of population over a number of years
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historical range of variation
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the known range of abundances of a population or species over some past time interval
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catch per unit effort
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a method which assume that the same effort is exerted by all hunters/harvesters per unit of time, as long as they have the same technology. this way, if you know the total time spent hunting, and you know the catch per unit of effort, you can estimate the total population
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continental shelves, which make up only _____% of oceans, provide over ____% of the fishery harvest
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10;90
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endangered
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any species which is in danger of extinction throughout all or a significant portion of its range
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threatened
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any species which is likely to become an endangered species within the forseeable future throughout all or a significant portion of its range
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local extinction
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occurs when a species disappears from a part of tis range, but persists elsewhere
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global extinction
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occurs when a species can no longer be found anywhere
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naturally about ___ species per year, on average become extinct
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1
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aren't you the most amazing girl in the whole world?
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yes. yes you are.
please don't forget that. |