Chapter 2: Economic Botany: the Use of Plants by Humans

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Chapter 2 Economic Botany the Use of Plants
by Humans

• BIO 223

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1st reading/writing assignment

• Due Feb. 15th two weeks from today
• On Evolutionany aspect as long as its
  scientifically valid.
• The article must be at least 6 pp. in length.
  Hard copy!
• Assignment should be about 1-1.5 pages double
  spaced and typed.
• summarize in one paragraph Come up with 3
  questions the article poses and state the answer
  to the questions
• Suggested magazines
• Discover
• National Geographic
• Scientific American

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faculty.saintleo.edu/miller

• Website for posted Power point lectures

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Some definitions

• Ethnobotanyuse of plants by indigenous people
• Economic botanyuse of plants in general (book
  says use by industrialized societies)

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Origins of Agriculture Pre-Agricultural societies

• Hunter-Gatherers have dominated Human history for
  gt150,000 years
• Didnt initially cultivate or domesticate
  organisms

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Where did agriculture begin?

• In mid-East, the heart of which is Iraq
• Began 10-12 thousand years ago
• Why did it begin there?
• Retreat of glaciers and end of last Ice Age
  (warming period)

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What is domestication?

• Domesticationprocess of cultivating a plant or
  animal so the organism becomes dependent on
  humans and vice versa
• Cultivationprocess of growing plants

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Traits of domesticated plants

• Conscious selection for
• Large size
• Fleshiness
• High oil content
• Lack of bitterness
• Unconscious selection for
• Non-shattering varieties
• Early germination
• Self pollinating or compatible

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Advantages and Disadvantages of switching to
Agriculture

• Advantages
• Supports more people (bigger population possible)
• Consistent food supply
• More calories available
• Higher quality of food
• Labor division

• Disadvantages
• More diseases (greater population density)
• More work

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Which came first? More people or agriculture?

• People
• Agriculture
• Whatever the answer, theres a feedback between
  the two.

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The Big Question (one of the biggest that could
be asked)

• Why is European civilization the source of most
  material wealth? That is, why did Europeans
  conquer the world and not Australian
  aborigines, the Inca, or Africans?

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Fertile Crescent?EuropeAgriculture left the
Fertile Crescent due to climate change
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Why did agriculture begin in the Near East and
spread to Europe?

• Mediterranean climate
• Winter wet and cool
• Summer dry and hot
• Seeds sprout and in Spring and mature by late
  summer
• Large seeded grasses
• Annuals

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Agricultural Origins Centers of Domestication
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Origins of Agriculture Fertile Crescent crops

• Large-seeded grasses
• (cereals)
• Barley
• Wheat

Barley
Wheat
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Origins of Agriculture Fertile Crescent

• Large seeded grass (cereal)
• Oats
• Legumes
• Lentils
• Garbanzo beans (chick peas)
• Other tree crops
• Apples
• Plums
• Cherries

OATS
OATS
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Food combining

• Legumes are important to combine with grains to
  make complete proteins
• Grains do not contain all amino acids in
  sufficient quantities (e.g. corn is low in
  lysine)
• Legumes therefore contain some missing amino
  acids

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Centers of Agriculture Origin Far East

• gt5,000 B.C.
• Millet (n. China)
• Rice (s. China)
• More recently
• Citrus (s. China)
• Hemp (n. China)
• Soybean (n. China)
• Peaches (n. China)

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Centers of Agricultural Origin China

• Millet is very important globally but less so in
  the U.S.
• Soybean is now one of the most important crops
  globally

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Centers of Agricultural Origin Southeast Asia

• Bananas
• Coconuts
• Sugar Cane
• Taro (dasheen)

TARO
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Centers of Agricultural Origin Mexico and
Central America

• Most are familiar
• corn
• beans
• avocado
• chili peppers
• squash
• sweet potato
• cotton
• cacao

Cacao
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Mexico and Central America Grains

• Amaranth (nearly a perfect proteinalmost no
  grain combining necessary)
• Corn and beans combined and often grown together
  (beans contain Nitrogen-fixing bacteria)
• Corn, beans, squash (the triad) are grown
  together often

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Agricultural Origins South America

• Potatoes
• Quinoa
• Perfect protein, like Amaranth

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Domestication involved changing plant traits

• Example Teosinte
• Few kernels6-12/cob (vs. 500 in corn)
• Shatter (no shatter in corn)
• No husk (husk in corn)
• Hard shell around seeds

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Conclusion

• Without agriculture and domestication of plants
  and animals, civilization would not be possible.
  In other words, we wouldnt write, use tools, or
  even be here. Ultimately, domesticated plants
  and animals created all culture.

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Plant Genetic Resources need to be preserved

• Monocultures are fields planted in one crop
• Disadvantages
• Such low diversity can lead to disease outbreaks
• Must use lots of pesticides
• Soils become depleted in nutrients (fertilizers
  must be used)

A healthy corn field
A soybean field with charcoal rot, a fungal
pathogen
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Polycultures are mixed/multi-species plantings

• Disadvantages
• More difficult to harvest on large scale (for
  market production)
• Advantages
• More diversity, less pest problems
• Better for soilless fertilizer may be needed
• Provides many different foods (for subsistence
  growers)

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In-situ vs. ex-situ conservation

• Germplasmgene pools of various domesticated and
  cultivated species
• In-situ
• Ex-situ

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Green Revolution

• Late 1940s-70s
• Widespread famine due to increase in human
  population

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World Population 1950-present
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Green Revolution Yields Increase
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But

• Widespread use of pesticides
• Irrigation resulted in loss of bodies of water
• Salinization (salt build-up) common
• Loss of biodiversity

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And

• Pesticides, mechanized farming equipment, and
  fertilizers expensive
• Furthermore, seed is expensive
• especially for poor farmers in developing
  countries

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• Plenty of food - yet the poor are starving
• The two faces of Niger Jeevan Vasagar in
  Tahoua, NigerMonday August 1, 2005The Guardian
  Waiting at YamaA total of 3.6 million people
  live in the regions of Niger affected by the food
  crisis. According to the most reliable estimate,
  some 874,000 people now need free food to
  survive.

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Natural plant products

• Plant secondary compoundswhy do plants have
  them?
• We can use them, too
• As poison or medicine (same thing in different
  doses)

My Favorite Strychnine