BIO220H1 Lecture Notes - Lecture 8: Plant Breeding, Corn Flakes, Soil Texture
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BIO220H1 Full Course Notes
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Document Summary
Quaternary period: (2. 68 mya) ice age with alternating glacial and interglacial periods. Holocene epoch: (10,000 years ago) interglacial period; development of agriculture, post-glacial phenomenon. Humans not adapted for folivory, plant foods need to be higher quality/less defended: fruits, seeds, tubers. Fruits: good food; selection for attractiveness to dispersal. Tubers and seeds: good food, energy-storage organs. Crops of antiquity: artificial selection on native plants. Independent origins in different places: key cultural innovations: store seeds, plant, cultivate. Grasses: wheat, rice, maize, barley, key evolutionary innovations: non-shattering seed heads, amylase evolution. Legumes: beans, lentils, chick peas (higher protein) Middle ages: crop rotation, draft animals. After middle ages: exchanges of crops, animals, tech. Human life transformed; nomadism replaced by stability, rise of cities. Ecological and evolutionary limitations of primitive cropping systems. Intrinsic growth performance of crops: limited areas suitable for growth, edaphic factors: soil moisture and fertility, soil exhaustion, buildup of insects, disease. Famines occurring, with much worse ones as predicted.
