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Blue Planet Video!
o pen the
door in the
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
! 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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- Spring '13