MEASURING POPULATIONS

1
MEASURING POPULATIONS

• pp. 383-387

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• birth rate of births per given time
• death rate of deaths per given time
• Growth rate the amount a population size changes
  in a given time

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GROWTH RATE

• Net reproduction
• r birth rate death rate
• Growth rate r b d/ total population
• If the value is , the population is growing
• If the value is -, the population is declining

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EXAMPLE of per capita rate

• In a rat cage containing 400 rats, 100 rats are
  born and 40 die.
• Growth rate r (b d) / total population
• r of births - of deaths
• total population
• r 100 - 40 60 0.15
• 400 400

5
What the per capita means

• You can estimate the next years population size
• EX. original population change new pop.
• 60 400 460
• How big would the population be the next
  generation?
• 460 x 0.15 69
• 69 460 529