ESS 120 Lecture 5 Outline of Last Lecture I. Description of Mayan CivilizationII. The Collapse of the Mayan CivilizationIII. Causes of collapseIV. Preventative measurements for erosion and soil degradationV. Diamond’s Roadmap to Failures of Group Decision Making Outline of Current Lecture I. Bushmen lecture continuedII. Introduction to salinization and waterloggingIII. Description of Mesopotamian CivilizationsIV. Drivers of collapse of MesopotamiaCurrent LectureI. Bushmen lecture continued- Bushmen currently located in Northwest Botswana- In recent study of 20 people randomly selected from streets of NYC, all ethnic groups represented in their DNA except the Bushmen genetic markers- Paintings in Africa of animals by Bushmen shows author beyond a doubt that they are not an inferior race  many murdered Bushmen found with horns of paint tied around them, proof that the Bushmen were the artists responsible for painting- When Europeans began colonizing Africa  Bushmen had no allies, were completely abandoned, even aboriginal peoples protection organization ignored their problems- European missionaries conquering Africa gave Africans two options: repent and be baptized or be taken as slaves (Bushmen chose neither, fought for survival of culture instead)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.- “Human beings are never more frightening than when they are convinced beyond doubt that they are right.”-- Rock paintings signed with imprint of hands  palms painted and pressed against stone- When Bushmen grow old/can’t continue moving constantly with herds of animals, the rest of the group gives as much food and water as they can spare, build a shelter of thorns for elderly to protect from animals, then move on and leave them behind  eventually leopard/hyena will break through shelter and eat them- If twins are born to a Bushman mother, must leave one underneath a bush, otherwise both will die b/c not enough resourcesII. Introduction to salinization and waterlogging- 10 million hectares of land lost every year b/c of salinization and waterlogging- Salinization: collection of salt in surface of soil as pure water evaporates from the soil and leaves behind solutes- Irrigation causes:o Salinizationo Waterloggingo Depletion and pollution of water supplieso Reduced yieldso Soil poisoning- Water logging: irrigation raises water table and pushes salts to topsoil/soil surfaceIII. Description of Mesopotamian Civilizations- Mesopotamia  modern day Iraq, located between Tigris and Euphrates rivers, lasted 2,500years, (began 3,000 BCE)- First time humans began living in cities, developed their own written language- Cities= city states, ruled by monarchs/religious leaders, governed by written law- Center of civilization shifted from Kish to Akkad (2,300 BCE)IV. Drivers of collapse of Mesopotamia- Center of civilization kept moving Northward… Why?o Environmental damageo Societies can’t respond to environmental problemso Climate changeo Hostile neighborso Loss of friendly trading partners- Why did Sumer collapse?o Open society  ethnic intrusion, lots of immigration into fertile valleyo Hostile neighbors (Semites)o Inability to respond to environmental damages- Alluvial soils didn’t allow water to drain through the profile = erosion of silts  irrigation caused water table to rise- Irrigation waters have heavy salt and silt loads because of lots of evaporation that’s occurring- Silt deposition in river channel (from erosion) + irrigation = raises water table- Limited water movement = salinization + waterlogging- Salty soils  more irrigation  more salinity  roots cannot pull water into plan because osmotic potential is reversed (water flows out of roots to dilute the soil solution)- Mesopotamian inventions: 60 interval clock, wheel, calendar- Mesopotamia = 17-25 million people at peak of civilization, 3-4 million people live there