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Measuring selection in human populations using the growth rate per generation.

Douglas Ewbank1

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Estimating evolutionary speed requires accurate fitness measures. Using generational growth, not annual, better reflects changes in human populations, avoiding underestimation of evolutionary rates.

Keywords:
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Area of Science:

  • Evolutionary biology
  • Population genetics
  • Demography

Background:

  • Estimating the speed of evolution relies on linking individual traits to fitness.
  • Common fitness measures include net reproduction rate and 1-year growth factor.

Purpose of the Study:

  • To evaluate the impact of different fitness measures on evolutionary speed estimates.
  • To highlight the importance of generational growth for human population studies.

Main Methods:

  • Comparison of evolutionary speed estimates using net reproduction rate versus 1-year growth factor.
  • Analysis of generational growth over the reproductive lifespan.
  • Application of methods to human population data from Kenya and Ukraine.

Main Results:

  • 1-year growth factor is not a true measure of intergenerational change.
  • Generational growth measures provide more accurate estimates of evolutionary speed.
  • Annual growth rates are overly sensitive to non-reproducing individuals.

Conclusions:

  • Generational growth is a more appropriate measure for studying evolutionary changes between generations, especially in humans.
  • Using 1-year growth rates can significantly understate the rate of evolutionary change in human populations.