EEB202H1 Lecture Notes - Lecture 3: Eragrostis Tef, Global Issue, Trans-Cultural Diffusion

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Lecture 3 -Origins of Agriculture
Food security
related to food supply and individual’s access to food
concern about how food production can keep up with population growth
= applied ecology
ecology = interaction b/t organisms and the environment
= the cultivation of plants and rearing of animals for food and other uses
the practice of agriculture = farming
= applied genetics
genetic alternation of plants and animals humans are now modifying
artificial selection
breeders have a specific goal for a specific crop [vs natural selection = no purpose]
High species diversity in tropical forests
rich bio-diversity
cutting down trees -> traumatic change in ecosystem
"beef for burgers” - driven by humans’ appetite for meat; make no sense to cut down trees to put
cows in
Types of agriculture - 2 ends of the spectrum; not all agricultures can be forced into 1 of these 2,
Shifting Cultivation
how agriculture started in many low land tropical areas
cut down the forest and burn the trees -> fertile fine ashes -> by the time the other fields are
burnt, soil has time to resemble nutriments
abandoned after 5-10years due to reduced soil fertility, weeds and pest build-up
naturally, forests can regenerate quite quickly
but this would only work with low human population densities and small plant areas
tropical forests are not very nutrient-rich
common in developing countries
often called “slash & burn” agriculture
cutting down diverse forest -> grow diverse crops (changing to monoculture is a
dramatic change)
mixed cropping
perfectly ecologically sustainable as long as human population densities are low
economics: mostly to feed own family and maybe sell a portion of it at the market
producing a single crop/plant species in a field at a time
agriculture in developed countries
tend to not work well in low tropical areas
large areas devoted to a single genetically uniform crop
high pesticide and fertilizer inputs
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