Agriculture Flashcards
Lec 21
Domestication
A change in the gene pool of a plant or animal resulting from a coevolutionary process
wolves -> dogs
How can domestication occur?
Humans manipulate plant or animal breeding to selectively develop particular phenotypic traits by choosing which will reproduce
in a controlled environment
can be behavioral or morphological
high yield and ability to survive farm conditions
Genetic bottleneck with GMOs
crop plants are often extensively inbred and not allowed to reproduce sexually in the field, limiting their gene pool and reducing variation needed to adapt to changing climate
farmers decide what to select for, no variance
GMOs
organisms whose genetic material has been artificially manipulated in a laboratory through genetic engineering
ex: weed control, pest resistance, reduced browning
Is this a crazy short-circuit of evolution?
genes move between kingdoms in nature quite regularly (virus DNA in humans)
Concern for Hybridization
wild population existing with gene modify selection, but not really a concern
Rapid evolution against antibiotics
Antibiotic use is widespread in agriculture for increasing yield and enabling high density
natural selection for the bacteria that survives antibiotics, results in rapid resistance
Resistance to pesticides
500 species of pests have evolved resistance to pestisides
Abiotic and biotic environment changes
distribution of ecosystems (deforestation!!)
biodiversity reduction
soil erosion
eutrophication
modify selection pressures, gene flow, genetic diversity
Haber-Bosch process + Eutrophication
Creates Nitrogen fertilizer from air and fossil fuels
planetary boundary of biochemical flows highly exceeded
pesticides do not break down, causes eutrophication and magnified up the food chain
Freshwater
agriculture uses up a lot of it
The Colorado river overused for agriculture, rarely reaches the sea, no delta habitat for fish
No longer a Nile floodplain that was good because of dam
three mechanisms and their consequences
domestication –> more bugs to eat crop –> lower yields
antibiotic use –> evolution of resistance –> health risks
gene flow changes –> hybridization –> more weeds –> higher cost
agriculture and human development
food production 12 kya
greater reliability of food
ability to stay in one place
how has agriculture changed our bodies?
disease, more reliable food but less nutrition, worse oral health, shorter
proximity between humans and animals, sanitation was poor
changes in the genome (lactose tolerance, immunity)
