Lecture 17 Flashcards
What is the consequence of domestication?
A change in the gene pool of a plant or animal resulting from a coevolutionary process.
Caused visible changes in the species compared to wild species.
What is artificial selection?
The process by which humans manipulate plant or animal breeding to selectively develop particular phenotypic traits by choosing which males and females will reproduce.
How does domestication occur?
- Breeder’s approach: breeding plants/animals that exhibit extreme values of a trait.
- Controlled Natural Selection: breeders do not choose which individuals reproduce, allow reproduction/survival to occur in a controlled environment.
What are the modern traits that we select in animals?
- Ability to survive stress (de-beaming, crowded conditions, caging).
- High production.
- Ability to survive on food not in their natural diet.
- Disease resistance.
What does it mean for plants to be selected for uniformity?
Plants are genetically modified to mature at the same time, so that they can be harvested at the same time.
Plants are modified to not seed (so farmers depend on yearly seed purchases).
What is the consequences of different Argo-ecosystems (Monoculture vs. Polyculture).
Highly reduced biodiversity.
- only the highest yield plants and animals persist to retain financial importance.
- many plant species are genetically modified.
- only highest yield species persist.
Why does it matter for plants to have less genetic diversity?
Modern crops could create a genetic bottleneck.
Crop plants are often inbred and not allowed to reproduce sexually in the field = limited gene pool and reduced variation needed to adapt (e.g. changing climate).
What are GMOs?
Organisms whose genetic material has been artificially manipulated in a lab through genetic engineering.
Creates combinations of plant, animal, bacteria, and virus genes that do not occur in nature or through traditional crossbreeding methods.
Example: herbicide resistance, pest resistance, reduced browning.
Are GMOs a crazy short-circuit of evolution?
GMOs are usually thought of as an unnatural process, but genes do move between kingdoms in nature.
There is a potential for hybridization —> transgenes modify selection in wild populations.
What are antibiotics used for? What do antibiotics cause in evolutionary terms?
Antibiotics use is widespread in agriculture for increasing yield and enabling high density.
Results in rapid resistance, significant concerns about loss of effectiveness and spread.
What are ways that agriculture has changed the planet?
- distribution of biomass
- deforestation/ecosystem displacement
- greenhouse gas emissions
- eutrophication
- soil erosion
- freshwater depletion and salinization
- biodiversity reduction
Explain the consequence of ecosystem displacement and fragmentation due to agriculture.
37% of earth is now used for agriculture of some kind.
Removal of entire tracts of ecosystems (e.g forests).
Agriculture land use is a huge driver of deforestation (flow on impacts: drought, fire).
Explain how agriculture is a major source of nitrous oxide, methane, and CO2.
Comes from enteric fermentation (livestock), fermentation, rice paddies.
Agricultural management (tillage, heavy grazing).
Loss of stored C in soils.
Explain the shift in biomass caused by agriculture.
Livestock now outweighs all wild mammals.
Explain eutrophication as a consequence of agriculture.
Around half of fertilizer is never taken up by crops - goes to the air or water.
Excess nutrients cause algal blooms, growth of parasites, fish kills, human health issues.
