AGRI 116 Week 3 Notes
AGRI 116 Week 3 Notes AGRI 116 001
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This 2 page Class Notes was uploaded by Erin Wade on Thursday September 8, 2016. The Class Notes belongs to AGRI 116 001 at Colorado State University taught by Andrew P. Norton in Fall 2016. Since its upload, it has received 18 views. For similar materials see Plants and Civilizations in Agricultural and Environmental Plant Sciences at Colorado State University.
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Date Created: 09/08/16
9/7/16 Domestication: Human Perspective Development of agriculture + sedentary lifestyle = Increased population density, expansion Domestication anthropogenic (human caused) evolution of a wild species to one which cannot survive without human assistance Domestication: Plant Perspective Evolution change in trait frequency over time Diversity need multiple versions of traits for trait frequency to change ● Mutations change certain traits ● Recombination mixes parents’ traits ● Migration introduces new traits into a population Selection this is the pressure that acts on diversity ● Humans select for traits associated with agriculture ● May result in loss of diversity Patterns of Domestication: “The Domestication Syndrome” The suite of traits which were selected for during domestication are considered the “domestication syndrome” ● Loss of seed dispersal ● Improved yield ● Synchrony of germination and flowering “Unintentional Domestication” Theory Initial cultivators would harvest plants which are most suitable for agriculture ● Seeds which “dispersed” during collection would fall to the ground and would not be harvested ○ Harvesters selected for: Lack of seed dispersal ● Only harvested the largest seeds ○ Harvesters selected for: Improved yield ● Only plants producing seeds at the time of harvest would be collected ○ Harvesters selected for: Synchrony of seed production and flowering How does domestication occur? Utilized → cultivated → semidomesticated → fully domesticated (need heavy human input) Selection and Diversity Diversity is a prerequisite for evolution with very few exceptions, diversity exists in all species (cheetahs are an exception) ● Selection changes levels of diversity ○ Strong selection for specific traits reduces diversity Differential selection for each variety can increase betweenvariety diversity ● Keeping specific seeds to plant the following year can increase the number of varieties Loss of Diversity Industrial monoculture farming relies on (nearly) genetically identical plants: ● Domestication syndrome ● Strong “selection” leads to dramatic reduction in a crops’ diversity Importance of diversity: allows crops to evolve (or humans to breed them) Movement to new environments ● New enemies: ○ Pests and disease ● Different Climates: ○ Temperature ○ Water ○ Human Uses ○ Day length