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81 Cards in this Set

  • Front
  • Back
of all human activities _______ has proven to be the most sustainable
What does it mean to "bank" farmers?

(in the US)
to pay farmers not to grow crops b/c there is enough production
Name the 2 ways in which people starve
undernourishment and malnourishment
-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
-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
Most of the world's food is provided by only ____ # of crop species, and ____ # of those privide over 80% of the total calories consumed
Name the 3 most vital world crops
1. wheat
2. rice
3. maize (corn)
What is forage?
crops grown as food for domestic animals
provides food for grazing animals w/o plowing and planting
plowed, planted, and harvested land that provides food for animals
the farming of food in aquatic habitats-both marine and freshwater (ex: carp, shrimp)
the farming of ocean fish (ex: oysters, mussels)
These farms are grown on rafts in intertidal zones
ecosystems created by agriculture, typically w/ low genetic, species, and habitat diversity
In farming, people try to _______ ecological succession, keeping it in an ________ stage
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
Crop rotation
(counteracts monoculture)
when different plants are planted in turn in the same field, with the field occasionally left fallow
What is Liebig's law of the minimum?
the idea that some single factor determines the growth and presence of a species
limiting factor
the factor whose availability is the least in comparison to the needs of the plant
chemical elements required by all living things in relatively large amounts (CHONPS)
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)
synergistic effect
a change in the availability of one resource affects the response of an organism to some other resource
3 major technological approaches to agriculture
1. modern mechanized agriculture
2. resource-based agriculture
3. bioengineering
Green Revolution
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
organic farming
farming that is more "natural" in the sense of not using artificial pesticides, and, more recently not using genetically modified crops
Genetically Modified Crops
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
Compared to unplowed soil, plowed soil has little _____ ________ and lacks ____ ______
organic matter; definite layers
Explain the Dust Bowl phenomenon
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
Explain the chemical effects of sedimentation on water bodies
eutrophication! nitrates and other fertilizers are carried down stream, enriching the water environment and promoting TOO MUCH BAD algae growth
Production of soil is
a. fast
b. slow
soil horizons
the series of layers soils are divided into over time
soil fertility
the capacity of soil to supply nutrients necessary for plant growth
contour plowing
plowing land along topographic contours, as much in a horizontal plane as possible (perpendicular to the slopes), thereby decreasing the erosion rate
No-till agriculture
aka conservation tillage
-combination of farming practices that includes not plowing the land, instead using herbicides to control weeds
biological control
the use of biological predators and parasites to control pests (ex/ ladybugs!)
integrated pest management
IPM uses a combination of methods to control agricultural pests, including biological and chemical agents.
terminator gene
makes crops sterile.
prevents GMCs from spreading and protects a corporation's market
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
the deterioration of lanf in arid, semi-arid, and dry sub-humid areas due to changes in climate and human activities
landscape perspective
the concept that effective management and conservation recognizes that ecosystems, populations, and species are interconnected across large geographic areas
the professional growing of trees
public service functions
functions performed by ecosystems for the betterment of life and human existence (ex: trees cleaning the air)
Leaves and roots in a tree are connected by 2 transportation systems
1. phloem
2. xylem
(outside of living bark)
transports sugars and other organic compounds down to stems and roots
(inside of livinig bark)
transports water and inorganic molecules upward to the leaves. water is transported by a sun-powered pump (evapotranspiration)
each species of tree has its own niche, determined by _______ and _______
water content of the soil ; forest tolerance of shade
an informal term used to refer to a group of trees. they can be small to medium-sized
2 major kinds of commercial stands
1. even-aged stands
2. uneven-aged stands
even-aged stands
all live trees begin growth from seeds and roots germinating the same year
uneven-aged stands
all the trees ini that area have at least 3 distinct age classes among them
old-growth forest
aka virgin forest
a forest that has never been cut
second-growth forest
a forest that has been cut and regrown
rotation time

the time between cuts of a stand
dominant trees
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
site quality

(think industrially)
the maximum timber crop the site can produce in a given time
the cutting of all trees in a stand at one time
alternatives to clear cutting

(there are 4)
selective cutting
shelterwood cutting
seed-tree cutting
cutting dead and less desirable trees first and later cutting mature trees, so that there are always young trees around
seed-tree cutting
removes all but a few seed trees to promote regeneration of the forest
selective cutting
individual trees are marked and cut ----> thinning
narrow rows of forests are cut, leaving wooded corridors
a stand of a single species planted in straight rows
sustainable forestry
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
certification of forestry
formal process to compare the actual practices of specific corporations or gov't agencies with practices that we believe to be consistent with sustainability
indirect deforestation
the loss of forests from pollution or disease
parks vs. preserves
parks are set aside for use by people.
preserves may be used by peopl, but is set aside for environmental reasons
an area undisturbed by people
maximum sustainable yield
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
minimum viable population
the estimated smallest population that can maintain itself and its genetic variability indefinitely
logistic carrying capacity
carrying capcity as defined by the logistic growth curve
optimum sustainable population
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
in the logistic growth curve, the greatest production occurs when the population is exactly ______ of the carrying capacity
time series
a set of estimates of population over a number of years
historical range of variation
the known range of abundances of a population or species over some past time interval
catch per unit effort
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
continental shelves, which make up only _____% of oceans, provide over ____% of the fishery harvest
any species which is in danger of extinction throughout all or a significant portion of its range
any species which is likely to become an endangered species within the forseeable future throughout all or a significant portion of its range
local extinction
occurs when a species disappears from a part of tis range, but persists elsewhere
global extinction
occurs when a species can no longer be found anywhere
naturally about ___ species per year, on average become extinct
aren't you the most amazing girl in the whole world?
yes. yes you are.
please don't forget that.