BIO220H1 Lecture Notes - Lecture 8: Amylase, Sumer, Crop Rotation
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BIO220H1 Full Course Notes
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Lecture 8: ecology of ancient and modern food. Production: quaternary period = last 2. 68 my, an ice age with alternating glacial and interglacial periods, humans (as genus homo) emerged about 2. Mya: agriculture a post-glacial phenomenon, about the last 10,000 years = holocene epoch, an interglacial period. Early humans: evolved and migrated as hunter/gatherers: no agriculture until. Ecological & evolutionary limitations of primitive cropping systems: intrinsic growth performance of crops. Limited areas suitable for growth: recall from bio120 that plant ranges of tolerance typically limited by (in order): temperature, water, npk. Soil exhaustion, buildup of insects, disease (compare. Janzen-connell effect: these limits were attacked by science. Issues in contemporary agriculture: return to the 1950s & 1960s: Famines occurring, with much worse ones predicted. Transition from manure to industrial chemicals: lawes: dramatic growth responses to chemical fertilizers, especially grasses to nitrates/ammonia, higher concentrations of compounds needed for optimal growth, n fertilizer from high-nitrate minerals (saltpeter, kno3 or nano3:
