Feeding People

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Feeding People

• Science 10

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Productivity

• Productivity the average amounts of new plant
  BIOMASS produced each YEAR per unit AREA

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Page 25
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(No Transcript)
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Ecosystem Productivity Levels (See table, p. 25)

• Estuary 40 000 kJ/m2/yr
• Swamp/Marsh 40 000 kJ/m2/yr
• Tropical Rainforest 40 000 kJ/m2/yr
• Temperate Forest 25 000 kJ/m2/yr
• Northern Coniferous Forest 15 000 kJ/m2/yr
• Savanna 13 000 kJ/m2/yr
• Agricultural Land 12 500 kJ/m2/yr
• Woodland and Shrubland 12 000 kJ/m2/yr
• Temperate Grassland 10 000 kJ/m2/yr
• Lakes and Streams 10 000 kJ/m2/yr
• Continental Shelf 7 000 kJ/m2/yr
• Open Ocean 5 000 kJ/m2/yr
• Tundra 3 500 kJ/m2/yr
• Desert Scrub 2 000 kJ/m2/yr
• Extreme Desert 1 000 kJ/m2/yr

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Feeding People

• In order to feed the worlds population, we need
  agriculture (whether growing plants or animals)
• Unfortunately, agricultural land has limited
  productivity which means that it is not the most
  efficient use of land
• Further, climate plays a large rule in
  productivity and many areas of human habitation
  have limited growing seasons

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Questions

• 1) What is the most productive land?
• 2) What is the least productive land?
• 3) Could we increase food production by farming
  in new places like the tropical rainforest? Why
  or why not? (read page 27

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• Most Productive green
• Least Productive yellow

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Food and Population Size

• The longer a food chain is, the less original
  energy from the sun is available to the final
  link in the chain
• Therefore, it is most efficient for humans to
  consume a plant based diet and limit the amount
  of animals/animal by-products that are included
  in a diet
• About 80 of humans eat a mostly grain-based diet

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Food Chains

• What would a food chain look like for
  vegetarians?
• What would a food chain look like for those who
  eat beef or chicken?
• What would a food chain look like for those who
  ate fish?
• Why is grain the best option?

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Pests and Monocultures

• In a monoculture (like most agricultural
  endeavours) pests can be a large problem
• If an insect, other organism or disease targets a
  given plan, it will run rampant in a monoculture
• As a result, farmers often need to use pesticides
  to control pests
• These pesticides can be passed through the food
  chain

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Consuming the Planet

• The worlds population tripled in the 20th
  century and continues to grow
• This is due to improved health care and access to
  food
• However, our ability to produce food is starting
  to be outpaced by population growth and without
  new technology, it will soon be impossible to
  feed everyone

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• What has happened over time? Explain the graphs
  ups and downs.

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Problems

• Page 24
• Questions 1-6
• Page 34
• Questions 1-7