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chapter notes

Environmental Science
Course Code
Carl Mitchell

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Chapter 8
x Every 5 seconds, somewhere in the world, a child starves to death
Food security: the guarantee of an adequate, reliable, and available food supply to people at all times
x Increased food production
o devoting more energy (fossil fuels) to agriculture
o planting and harvesting more frequently
o increased use of irrigation, fertilizers, pesticides
o increasing the amount of cultivated land
o developing (through crossbreeding and genetic engineering) more productive
crop/livestock varieties
undernourishment: people who receive less than 90% of their daily caloric needs (mainly in developing)
x economic, 1/5 of world’s people live on > $1 a day, more than half live on > $2 a day
overnutrition: receiving too many calories each day (mainly in developed)
Five A’s: Availability, Affordability, Accessibility, Acceptability, Adequacy
Malnutrition: shortage of nutrients the body needs (vitamins and minerals) can lead to disease
Green Revolution: methods and technologies to increase crop output per unit area of cultivated land
x extensification (more land) to intesnsification (more productivity from unit of land)
x Norman Borlaug specially bred type of wheat
Industrialized agriculture: applying synthetic fertilizers, chemical pesticides, irrigation, using heavy
x Beneficial for biodiversity and natural ecosystems negative impacts on environment
o Monocultures made planting and harvesting efficient
o reduced biodiversity; susceptible to viral diseases, fungal pathogens or insect pests
o narrowing human diet 90% of food consumed comes from 15 crop, 8 livestock species
Biofuels (organic materials that are converted into liquid or gaseous fuels for use in internal combustion
engines replacing oil/natural gas)
o corn Æ ethanol (efficient alcohol fuel that can be mixed in proportions with gasoline)
o conflict of interests
o Increased demand Æ higher prices and scarcities of basic grains
o Accelerated deforestation, forested land Æ production of food grains
Pest: any organism that damages crops that are valuable to us
Weed: any plant that competes with our crops
Biological control (biocontrol):the enemy of ones enemy is ones friend” using organisms that prey
or parasitize pests/weeds without having to use pesticides
Bacillus thuringiensis (Bt): a naturally occurring soil bacterium that produces a protein that kills many
caterpillars and larvae of some flies and beetles
x Pest might evolve to deal with biocontrol agent Æ relocated
x Control agent becomes invasive and affects nontarget organisms
Integrated pest management (IPM): numerous techniques are integrated to achieve long-term
suppression of pests (biocontrol, use of chemicals, close monitoring of populations, habitat alteration,
crop rotation, transgenic crops, alternative tillage methods, mechanical pest removal)
Pollination: the process by which male sex cells of a plant (pollen) fertilize female sex cells of another
plant through wind, animals, insects
x 73% of cultivars are pollinated by bees, 19% by flies, 5% by wasps, 5% by beetles, 4% by moths
and butterflies, 6.5% bats, 4% birds
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