Unit 5 Flashcards
agricultural/Neolithic revolution
Agriculture first appeared approx. 12,000 years ago, and transitioned from hunter-gatherers to farmers
Which changed the way humans worked entirely. Created permanent villages and eventually allowed cities to form, which creates cultural changes
Agribusiness
agriculture becomes commercial and industrialized
Mechanization
Farming starts to become mechanized with the development of the internal combustion engine and increased harvest of cheap fossil fuels allowed farmers to invest more in machines than people.
This wasn’t necessarily better but it made more economic sense than paying and housing workers
mechanization works better with monocrops
Furrow Irrigation
Oldest, cheapest easiest form of irrigation
Farmers dig trenches between rows of crips and then fill them with water.
However, is only 65% effective because most of the water evaporates, drains out, etc
Flood Irrigation
Flood the whole field and let it soak into the soil
More disruptive but more efficient (70-80%)
spray irrigation
Like a sprinkler (the one that is most common)
Water is pumped through pipes to sprayer heads and sprayed across the field
More expensive but more efficient (75-95%)
drip irrigation
Super expensive, has a nozzle for each individual plant coming from pipes that must stretch across the entire area. However, is targeted and thus less weed growth
>95% effective but SO expensive
drawbacks of irrigation
Groundwater supply: is often used to support irrigation, but this greatly drains this resource. We currently use this unsustainably. Can cause soil compaction as well as salt water infiltration in freshwater wells
Waterlogging: soil remains under the water too long, root growth and health deteriorates due to lack of oxygen
Salinization: small amounts of salts in the water become concentrated in the soil once the water evaporates. This can become toxic and prevent plant growth
Aquifers
large sources of groundwater. Overuse has caused many to shrink and, due to the rate of withdrawal, it is currently thought of as a non-renewable source.
fertilizers (positives/negatives)
Used to boost the nutrient content of the soil in order to grow more crops, drastically increases crop yields
petroleum based, so you have to harvest oil (lots of pollution).Increases carbon output. since they are easy to make, they are often overused. Extra runs off into local waterways. This leads to algal blooms which removes dissolved oxygen and destroys water ecosystems
synthetic vs organic fertilizers
Synthetic: Petroleum based, Cheap and easy to use/transport, Also allows you to target nutrients for specific crops which makes them more effective
Organic: Old school, Made of organic material (animal waste, plant waste), Limited used based on availability and transportation
Genetically Modified Organisms (GMOs)
Can modify crops to resist pests and harsh conditions, Modified to produce specific nutrients, Organisms can be modified to produce pharmaceuticals (ex. Bacteria producing insulin), Can modify things to grow faster, more yield.
However, there are some concerns about the ethics and safety of using and consuming GMO products
CAFOs
ykyk
growing demand for meat
As wealth and affluence increases, so does consumption of animal based foods. Increased use of CAFOs to meet demand
Free Range animals
Opposite of CAFO model, animals are raised on pasture and open space as opposed to a feedlot. Becoming increasingly popular mostly because it’s ethically better. Also good since disease spreads less and they can help the biodiversity of the pasture.
Overfishing
Oceans have always been seen as a limitless resource, but we have learned otherwise. Overfishing of key species has drastically disrupted food webs across the world and lead to the rapid decrease in marine biodiversity. Increased demand for seafood doesn’t help.
Fishing methods: gill net
A long net is suspended in the water like a curtain- fish swim into it and get their gills caught in it and can’t escape
It is hard to target specific species = high bycatch, but only to marine species
Fishing methods: long line
A long line of hooks spread out over hundreds of meters. Depth can be changed to target specific fish
Not very precise and has high bycatch- especially harmful to birds
Fishing methods: purse seine
Like a gill net. A long curtain of netting encircles a school of fish. Once the loop is closed, the bottom is closed and the net is hauled in
Low bycatch in general but any species swimming near or in the school will be caught (ex sea lions)
Fishing methods: pole and line
Like traditional fishing, Each fisherman catches one fish at a time with a rod
Low bycatch and a more sustainable small scale method
However, lowest income because it isn’t dependable or industrial
Fishing methods: trapping
Large cages (also called traps or pots) are dropped to the bottom and left for a set period of time
Fisherman returns later and brings the trap up to sort through the catch
Tends to be lower bycatch but still can harm non-target species
Fishing methods: trawling and dredging
Similar methods involving dragging a large net behind the boat
Trawling occurs above the bottom floor, dredging drags it across the bottom
High bycatch and highly destructive to local ecosystems, especially dredging (overall just bad bad bad)
consequences of modern fishing
Fishery collapse, economic collapse, decrease of biodiversity, bycatch, pollution, the list goes on
aquaculture
Raising aquatic organisms for food in a controlled environment (basically agriculture for marine species)
Offsets demand for wild marine stocks, but has drawbacks like CAFOs do
