10/3/24 Flashcards
What is an example of freshwater overuse?
Aral sea
What is the culprit of Aral sea’s freshwater overuse?
Soviet cotton
What was the reason for the Green Revolution and what was the goal?
1960: scarcity of new arable land
Goal: increases crop output per area land
What was the purpose of cultivars during the Green Revolution?
- Increased yield
- Drought- and salt-tolerant
What were the outcomes of the intensive agriculture during the Green Revolution?
Fertilizer pollution
Pesticide pollution
Water depletion (irrigation)
Fossil fuel use
What would happen without the Green Revolution?
much greater loss of forests, wetlands, damage to other ecosystems
Why are monocultures an issue?
Economically efficient, but risk of “all eggs in one basket”
Reduced global diversity of crop plants
Why is pesticide use an issue?
Pesticides gradually become less effective as pests evolve resistance
Few pests that survive pesticide (because happen to be genetically immune)
Reproduce and pass on pesticide resistance genes to the next generation
Genetically Modified Food Organisms (GMOs)
Organisms whose genetic constitution has been altered by engineers with a specific outcome in mind
What is the result of using GMOs
Organisms grow bigger and faster
What is the purpose of GMOs?
Attempt to ramp up food increase
Artificial selection
manipulating organism’s genetic material by selecting mating, harvest
Artificial selection is a selection of
who mates with who
Examples of artificial selection
different dog breeds
All come from same genetic stock (wolves)
Teosinte → corn
Wild mustard (origin)
Cabbage - suppression of internode length
Broccoli
Kale
Cauliflower
Kohlrabi
Genetic engineering
adding, deleting, or changing segments of DNA
Recombinant DNA
combination of original DNA plus some modification
What is an example of recombinant DNA?
Bt-protected crops
Soil bacterium, Bacillus thuringiensis
Produces toxic to defend against predators
Toxin-producing gene is taken → Bt endotoxin
95% U.S. soybeans, 85% corn, and 90% cotton GM
US = 40% global GMO production)
Scientific Concerns About GMOs (least to most likelihood):
Human health risks
- No evidence suggesting GMOs affect human health
Can tansgenes for pest resistance “jump” from crops to weeds (–> “superweeds”)?
Pests will evolve resistance to Gm crops just as with pesticides?
Socioeconomic & Political Concerns of GMOs
Ethics of “playing God?”
Food supply risk?
- Adequate testing? Is outside oversight adequate?
Benefits of GMOs
Increase food production without nature conversion
Less pesticide use
What is one way people are preserving crop diversity?
Seed banks to preserve native cultivars (“living museums”)
E.g., Svalbard Global Seed Vault
Feedlot agriculture
Increased meat consumption → animals raised in feedlots (CAFOs) Concentrated Animal Feeding Operations
What are the upsides of feedlot agriculture?
Energy-rich food
Extremely high densities
Downsides of feedlot agriculture
Chickens are confined to small spaces
Start to get hyper aggressive
Chicken beaks are snipped off
Eutrophication
over-fertilization of the natural environment
In eutrophication, Phytoplankton are supplied with ____ and ____, which leads to extreme phytoplankton growth
sulfur; phosphorus
CAFO environmental impacts
Conc waste production, polluting air and water
Methane (GHG)
- Greenhouse gas
Ammonium
Sulfide
- Rotten eggs
Intensive use of antibiotics, growth hormones, some of which persist
How is grain feed demand calculated?
kg feed/kg produced
____ has the greatest gain feed demand (____ kg feed/kg produced)
Beef; 20
______ has the lowest grain feed demand (less than ___ kg feed/kg produced)
Chicken
How is energy demand calculated?
energy/kg produced
______ has greatest energy demand (energy/kg produced)
Beef
_____ have second greatest energy demand (energy/kg produced)
Eggs
How is GHG production calculated?
GHG emissions/kg produced
______ has greatest GHG emissions/kg produced
Beef
______ has lowest GHG emissions/kg produced
Chicken
How is water demand calculated?
water/kg produced
What animals have the greatest demand of water?
Cow
What resource has the least demand of water?
Eggs
How many liters of water/kg produced for beef?
700
How many liters of water/kg produced for eggs?
less than 50 liters
What the Earth’s total biomass of humans and domesticated cows?
Domesticated = 630 Mt
Humans = 390 Mt
T or F: Humans have more biomass than cows
F: cows have more biomass than humans
