Biology 2500: Botany

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Lecture 26

• Biology 2500 Botany
• Chapter 34 The Human Prospect

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Learning Objectives
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Hunter-Gatherer Lifestyle

• Requires movement
• Skills for survival most critical
• Hunting
• Gathering
• Because of movement, towns not possible
• Multiple children not possible

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Benefits of Agriculture

• Agriculture allowed for sedentary life
• Specialization of skills became possible with
  towns
• Industrialization possible too
• Larger families now possible

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Population Increasing Quickly

• 2.5 billion in 1950
• 6 billion in 2000
• Current reproduction
• 165 each minute
• 240,000 daily
• 88 million yearly

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Challenges for Future Agriculture

• Irrigation
• Problem drinking water is becoming limited
• Fertilizers
• Expensive, esp. for developing nations
• Impact drinking water quality
• Improved crops
• Higher yield protein content sometimes require
  more water fertilizer!
• Pesticides
• Bad for people environment

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Agricultures Answers

• Hybrid maize
• Strains to be crossed are grown in alternating
  rows
• Tassels are removed from one strain
• Resulting hybrid offspring are better
• More uniform (better for machinery)
• Easier to harvest
• Higher yield

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A New, Interesting Grain

• Triticale a cross between wheat (Triticum) and
  rye (Secale)
• Benefits
• Winter hardiness disease resistance of rye
• High yield quality of wheat

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Importance of Genetic Diversity

• Irish potato famine of 1846-1847 due to genetic
  uniformity among potato plants
• Unable to resist blight mold, Phytophthora
  infestans
• In three years, population shrank from 8.5
  million to 6.5 million
• 2 million Irish died in just 3 years
• Resistant strains of potatoes have been found
  bred to make better commercial strains

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Pine Tree Clones?

• Research being done to clone pine trees
• Why?
• Given potato history, is this research a wise
  thing?

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7th Inning Stretch