Lectures6-7_4pp

Turtles are heavy blue planet video enough to o pen

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Unformatted text preview: are heavy Blue Planet Video! enough to o pen the door in the net What demographic information do you need to know to answer?! Model predictions of the effect of headstarting vs.! Turtle Excluder Devices (TEDS)! Human population growth: do humans have a K? Crowder et al. 1994! ?? Nt = N0ert ! -we keep raising K through technology, but it relies heavily on stored energy (fossil fuels)… at least for now! -there must be a physical ceiling, though.! ! Heppell et al. 1996! Appendix (OPTIONAL for your edification only): ! Deriving density dependent population growth:! Why do developed countries have low r and stable populations? Are people being altruistic in the developed world or are they acting in their own self-interest? Why don t cheaters prosper? Discussion on Thursday…! Some algebraic massage, to turn this into the logistic eqn…! dN/dt = [(b0 - aN) - (d0 + cN)]N! ! Re-arrange to get:! dN/dt = [(b0 - d0) - (a+c)N]N! Logistic population growth: including density dependence! Birth and deaths depend on N:! Births (b) = b0 - aN! Deaths (d) = d0 + cN! ! (a and c are just constants that require describe the strength of density dependence)! ! Multiply by 1: [(b0 - d0)/ (b0 - d0)]! ! dN/dt =! (b0 - d0)! [! [(b0 - d0)! [(b0 - d0)! _! (a+c)! [(b0 - d0)! Substitute back into dN/dt = (b-d)N! Birth rate! Death rate! ! N! Let K = ! ! dN/dt = [(b0 - aN) - (d0 + cN)]N! N! dN/dt = r (b0 - d0)! (a+c)! [ 1 - (1/K)N]N! dN/dt = rN[1-(N/K)]! Logistic equation!!...
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