8th Chapter Vocab Flashcards
Thomas Malthus (1766-1834)
British economist who maintained that increasing human population would eventually deplete the available food supply until starvation, war, or disease arose and reduced the population
IPAT model
A formula that represents how humans’ total impact (I) on the environment results from the interaction among three factors: population (P), affluence (A), and technology (T)
demography
a social science that applies the principles of population ecology to the study of statistical change in human populations
demographer
a social scientist who studies the population size, density, distribution, age structure, sex ratio, and rates of birth, death, immigration, and emigration of human populations
total fertility rate (TFR)
the average number of children born per female member of a population during her life time
replacement fertility
the total fertility rate (TFR) that maintains a stable population size
rate of natural increase (natural rate of population change)
the rate of change in a populations’s size resulting from birth and death alone, excluding, excluding migration.
demographic transition
a theoretical model of economic and cultural change that explains the declining death rates and birth rates that occurred in western nations as they became industrialized. the model holds that industrialization caused these rates to fall naturally by decreasing mortality and by lessening the need for larger large families. parents would thereafter choose to invest in quality of life rather that quantity of children
life expectancy
the average number of years that individuals in particular age groups are likely to continue to live
pre-industrial stage
the first stage of the demographic transition model, characterized by conditions that defined most human history. in pre-industrial societies, both death rates and birth rates are high
industrial stage
the third stage of the demographic transition model, characterized by falling birth rates that close the gap with falling death rates and reduce the rate of population growth
post-industrial stage
the fourth and final stage of the demographic transition model, in which both birth and death rates have fallen to a low level and remain stable there, and populations may even decline slightly
family planning
the effort to plan the number and spacing of one’s children so as to offer children and parents the best quality of life possible
contraception
the deliberate attempt to prevent pregnancy despite sexual intercourse
birth control
the effort to control the number of children on bears, particularly by reducing the frequency of pregnancy
reproductive window
the portion of a woman’s life between sexual maturity and menopause during which she may become pregnant
transitional stage
the second stage of the demographic transition model, which occurs during the transition from the pre-industrial stage to the industrial stage. it is characterized by declining death rates but continued high birth rates
demographic fatigue
an inability on the part of governments to address overwhelming challenges to population growth
no-till
agriculture that does not involve tilling (plowing, digging, harrowing, or chiseling) the soil. the most intense form of conservation fatique
cover crops
a crop that covers and anchors the soil during times between main crops, intended to reduce erosion
agriculture
the practice of cultivating soil, producing crops, and raising livestock for human use and consumption
cropland
land that people use for raising plants for food and fiber
rangland
land used for grazing livestock
sustainable agriculture
agriculture that can be practiced in the same way and in the same place far into the future. sustainable agriculture does not deplete soils nor reduce the clean water and genetic diversity essential to long-term crop and livestock production
substance agriculture
the oldest form of traditional agriculture in which farming families produce only enough food for themselves
industrial agriculture
a form of agriculture that uses large-scale mechanization and fossil fuel combustion, enabling farmers to replace horses and oxen with more powerful means of cultivating, harvesting, transporting, and processing crops. other aspects include irrigation and the use of inorganic fertilizers, the use of chemical herbicides and pesticides reduce competition from weeds and herbivory by insects
traditional agriculture
biologically powered agriculture in which human and animal muscle power, along side with hand tools and simple machines, perform the work of cultivating, harvesting, storing, and distributing crops
monocultures
the uniform planting of a single crop over a large area
polyculture
the planting of multiple crops in a mixed arrangement or in close proximity. an example is some traditional native american farming that mixed maize, beans, squash, and peppers
parent material
the base geological material in a particular area
bedrock
the continuous mass of solid rock that makes up earth’s crust
weathering
the process by which rocks are broken down, turning large particles into smaller particles. weathering may proceed by physical, chemical, or biological means
humus
a dark, spongy, crumbly mass of material made up of complex organic compounds, resulting from the partial decomposition of organic matter
horizon
a distinct layer of soil
soil profile
the cross-section of a soil as a whole, from the surface to the bedrock
leaching
the process by which solid materials such as minerals are dissolved in a liquid (usually water) and transported to another location
irrigation
the artificial provision of water to support agriculture
waterlogging
the saturation of soil by water, in which water table is raised to the point that water bathes plant roots. Waterlogging deprives roots of access to gases, essentially suffocating them and eventually damaging or killing the plants
salinization
the buildup of salts in surface soil layers
fertilizer
a substance that promotes plant growth by supplying essential nutrients such as nitrogen or phosphorus
organic fertilizer
a fertilizer made up of natural materials (largely the remains or wastes of organisms), including animal manure; crop residues, fresh vegetation, and compost
compost
a mixture produced when decomposers break down organic matter, such as food and crop waste, in a controlled environment
conservation reserve program
U.S. policy in farm bills since 1985 that pays farmers to stop cultivating highly erodible cropland and instead place it in conservation reserves planted with grasses and trees
soil degradation
a deterioration of soil productivity, resulting primarily from forest removal, cropland agriculture, and overgrazing of livestock
land degradation
a general deterioration of land that diminishes its productivity and biodiversity, impairs the functioning of its ecosystems, and reduces the ecosystem services the land can offer us
dust bowl
an area that loses huge amounts of topsoil to wind erosion as a result of drought and/or human impact. first used to name the region in the North American great plains severely affected by drought and topsoil loss in the 1930’s. the term is now used to describe that historical event and others like it
conservation districts
a county-based entity created by the soil conservation service (now the natural resources conservation service) to promote practices to conserve soil
natural resources conservation service (NCRS)
u.s. agency that promotes soil conservation, as well as water quality protection and pollution control. prior to 1994, known as the soil conservation service
overgrazing
the consumption by too many animals of plant cover, impending plant regrowth and the replacement of biomass. overgrazing can exacerbate damage to soils, natural communities, and the land productivity for further grazing
contour farming
the practice of flowing furrows sideways across a hillside, perpendicular to its slope, to help prevent the formation of rills and gullies, the technique is names so because the furrows follow the natural contours of the land
terracing
the cutting of level platforms, sometimes with raised edges, into steep hillsides to contain water from irrigation and precipitation, terracing transforms slopes into series of step like staircases, enabling farmers to cultivate hilly land while minimizing their loss of soil to water erosion
intercropping
planting different types of crops in alternating bonds or other spatially mixed arrangements
shelterbelts (windbreaks)
a row of trees or other tall plants that are planted along the edges of farm fields to break the wind and thereby minimize wind erosion
conservation tillage
agriculture that limits the amount of tillage (planting, digging, harrowing, or chiseling) the soil
crop rotation
the practice of alternating the kind of crop grown in a particular field from one season or year to the next
genetically modified food
food derived from a genetically modified organism
genetically modified organism (GMO)
an organism that has been genetically engineered using recombinant DNA technology
genetic engineering
any process scientists use to manipulate an organism’s genetic material in the lab by adding, deleting, or changing segments of its DNA
landrace
a locally adapted domesticated variety of agricultural crop native to a particular area
transgenic
term describing an organism that contains DNA from another species
transgene
a gene that has been extracted from the DNA of one organism and transferred into the DNA of an organism of another species
undernutrition
s condition of insufficient nutrition in which people receive less than 90% of the daily caloric needs
food security
an adequate, reliable, and available food supply to all people at all times
malnutrition
the condition of lacking nutrients the body needs, including a complete complement of vitamins and minerals
green revolution
an intensification of the industrialization of agriculture in the developing world in the second half of the 20th century that has dramatically increased crop yields produced per unit area of farmland. practices include devoting large areas to monocultures of crops specially bred for high yields and rapid growth; heavy use of fertilizers, pesticides, and irrigation water; and sowing and harvesting on the same piece of land more than once per year or per season
Norman Borlaug (1914-2009)
american agricultural scientist who introduced specially bred crops to developing nations in the 20th century, helping to spur the green revolution
monoculture
the uniform planting of a single crop over a large area. characterizes industrial agriculture
biofuel
fuel produced from biomass energy sources and used primarily to power automobiles. examples include ethanol and biodiesel
ethanol
the alcohol in beer, wine, and liquor, produced as a biofuel by fermenting biomass, generally from carbohydrate-rich crops such as corn
sustainable agriculture
agriculture that can be practiced in the same way and in the same place for into the future
feedlot
a huge barn or outdoor pen designed to deliver energy-rich food to animals living at extremely high densities. also called a factory farm or concentrated animal feeding operation (CAFO)
seed bank
a storehouse for samples of the world’s crop diversity
pollination
a plant-animal interaction in which one organism (for example, a bee or a hummingbird) transfers pollen (containing male sex cells) from flower to flower, fertilizing ovaries (containing female sex cells) that grow into fruits with seeds
pest
a pejorative term for any organism that damages crops that are valuable to us. the term is subjective and is defined by our own economic interests and is not biologically meaningful
pesticide
an artificial chemical used to kill insects, plants, or fungi
weed
a pejorative term for any plant that competes with our crops. the term is subjective and is defined by our own economic interests and is not biologically meaningful
bacillus thuringiensis (Bt)
a naturally occuring soil bacterium that produces a protein that kills many pests, including caterpillars and the larvae of some flies and beetles
biological control (biocontrol)
control of pests and weeds with organisms that prey on or parasitize them, rather than with pesticides
integrated pest management (IPM)
the use of multiple techniques in combination to achieve long-term suppression of pests, including biocontrol, use of pesticides, close monitoring of populations, habitat alteration, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal
organic agriculture
agriculture that does not use synthetic fertilizers or pesticides but instead relies in biological approaches such as composting and biocontrol.
aquaculture
the cultivation of aquatic organisms for food in controlled environments
