Biological Anthropology Lab Human Population

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Biological Anthropology LabHuman Population

• Michelle Y. Merrill, Ph.D.

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Ernst Mayr Summarizes Darwins Argument
forEvolution via Natural Selection

• Fact 1 organisms reproduce exponentially
• Fact 2 population size generally constant
• Fact 3 resources limited
• Inference 1 The Struggle for Existence
• Fact 4 organisms vary
• Fact 5 variation heritable
• Inference 2 non-random survival and
  reproduction
• Inference 3 accumulation of favorable
  characteristics ? adaptation

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How to be a human?
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Fact 1 All organisms could increase population
exponentially.

• The greatest shortcoming of the human race is
  our inability to understand the exponential
  function.
• -Albert A. Bartlett, Physicist

Growth rate 95-00 1.37 00-05
1.24 05-10 1.17
(198,000 years)
7 annual growth doubles every decade!
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Which would you rather?

• 1,000,000.00 right now OR
• A penny today, that would double every day for a
  month
• Day 2 0.02
• Day 3 0.04
• Day 4 0.08
• Day 5 0.16
• Day 30 5,368,709.12

Thats the POWER of exponential growth!
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Exponential Population Growth
19 Kids and Counting At the Duggars
reproductive rate, how many generations would it
take for the Duggar population to exceed Earths
present population?
Duggar Family, Arkansas
19 Children 361 Grandchildren 6,859
Great-grandchildren 130,321 Great-great-grandchild
ren 2,476,099 5th generation 47,045,881 6th
generation 893,871,739 7th generation 16,983,563
,041 8th generation
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The Lily Pond Parable

• If a pond lily doubles every day, and it takes 30
  days to completely cover a pond
• At what point would preventative action become
  necessary to prevent unpleasant events?
• On what day will the pond be 1/2 covered?
• 1/4 covered?
• How much would it help if we could double the
  size of the pond?
• With respect to human population and
  environmental degradation, what corresponding day
  is it for the world?

Adapted from http//www.ecofuture.org/pop/facts/ex
ponential70.html
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http//youtu.be/8x98KFcMJeo
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Population Growth Rates by country, 2006
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Population Growth Explained with Ikea Boxes
http//www.gapminder.org/videos/population-growth-
explained-with-ikea-boxes/