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4. Effects of population structure on dynamics a. Sex ratio b. Age structure c. Life tables

4. Effects of population structure on dynamics a. Sex ratio b. Age structure c. Life tables d. Life history 1) Survivorship patterns 2) Age-specific birth rates 3) Life history diversity. Ecology. the study of the distribution and abundance of organisms. dN/dt = rN.

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4. Effects of population structure on dynamics a. Sex ratio b. Age structure c. Life tables

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  1. 4. Effects of population structure on dynamics a. Sex ratio b. Age structure c. Life tables d. Life history 1) Survivorship patterns 2) Age-specific birth rates 3) Life history diversity

  2. Ecology the study of the distribution and abundance of organisms

  3. dN/dt = rN r > 0 population will grow r = 0 population won’t change r < 0 population will shrink

  4. Fig. 52.8 The exponential model for population growth

  5. dN/dt = r N [(K - N)/K] For: r=0.1 K=100 if N = 10 dN/dt = .1 (10) [(100 - 10)/100] = .1 (10) (.9) = .9 if N = 99 dN/dt = .1 (99) [(100 - 99)/100] = .1 (99) (.01) = .099

  6. Fig. 52.11 The patterns of exponential and logistic population growth

  7. What do I need to know about these models? ExponentialLogistic Pattern: J-shaped S-shaped Equation*: dN/dt = rN dN/dt = rN[(K-N)/K] Assumptions: -growth rate constant growth rate decreases with pop size -unlimited env. carrying capacity * Know what each term means and how changes in the terms affect the pattern of population growth.

  8. Fig. 52.22

  9. A Life Table Number Probability of #Offspring born Age aged x survival to x to females aged x 0 600 1.0 0 1 300 0.5 0 2 240 0.4 2 3 60 0.1 3 4 30 0.05 5 A model for growth of an age-structured population: Nt+1/ Nt = S (probability of survival to x)(#offspring at x)

  10. Fig. 52.3

  11. Variation in life history among plants Live long, reproduce once and die Live not so long, reproduce early Live long, begin reproduction late

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