AGRI 116 1nd Edition Lecture 5 Outline of Last Lecture I. Origins of AgricultureII. Spread of Agriculturea. Carrying CapacityOutline of Current Lecture II. Domestication III. The Role(s) of Selection and Diversity Current LectureDomestication: Human PerspectiveDevelopment of agriculture + sedentary lifestyle = Increased population density, expansion of agriculturalist societies, technological advancementDomestication (formal definition) – the anthropogenic evolution of a wild species to one that cannot survive without human assistanceEvolution- a change in the frequency of a trait (or gene) over timeWhat is needed for trait frequency to change?Diversity: Need multiple versions of traits!1. Mutations  Change certain traits2. Recombination  Mixes parents’ traits3. Migration  introduces new traits into a populationSelection: This is the pressure that acts on diversity1. Humans select for traits associated with agriculture2. May result in a loss of diversityPatterns of Domestication: “The Domestication Syndrome”The suite of traits which were selected for during domestication are considered the “domestication syndrome”These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.What are the biological differences between modern groups and wild species (progenitors)?The Domestication Syndrome:Domesticated plants differ from their wild progenitors (ancestor/parent/relative) in several ways:o Loss of seed dispersalo Improved yieldo Synchrony of germination and flowering “Unintentional Domestication”Theory: Initial cultivators would harvest plants that are most suitable for agriculture:o Seeds which “dispersed” during collection would fall to the ground and would not be harvestedo Harvesters selected for: lack of seed dispersalo Only the largest seeds would be harvestedo Harvesters selected for: improved yieldo Only plants producing seeds during harvest would be collectedo Harvesters selected for: synchrony of seed production and floweringTypes of DomesticationPrimary: Domesticated in the same area a plant grows naturally (wheat, maize, etc.)Secondary: Transported as an agricultural weed (unintentional movement), then subsequently domesticated (oats, rye)Trans-domestication: Intentionally transported to a new environment then domesticated (tomatoes, sugar beet)Selection and DiversityDiversity is a pre-requisite for evolution: with very few exceptions, diversity exists in all specieso Selection changes levels of diversityo Strong selection for specific traits reduces diversityDifferential selection for each variety can increase between-variety diversityo Keeping specific seeds to plant the following year can increase the number of varietiesLoss of DiversityIndustrial mono-culture requires genetically identical plants:o Domestication syndromeo Strong “selection” leads to a dramatic reduction in a crop’s diversityImportance of DiversityAllows crops to evolve (or humans to breed them.Movement to new environment o New enemies: pestso Different climates: Temperature Water Human uses Day lengthDifferent needs by humans in the