1. Friday 3/7 • Pop Quiz #7 • Turtles and Snakes ID Quiz • Notes on population math from Chs 9 and 10 • Lab 4B • Lab 4A - 15 SP only (for homework) 30 (lab 7) + 20 (PQ 7) + 15 (S&T ID) + (10 wk8Eng) = 75!

2. Pop Quiz #7

3. Snakes begins on next slide

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14. We’ve talked about (at least) one way to determine if a population is growing • ?

15. Rate?

16. Rate? • Variable per time

17. Rate? • Variable per time • N, t N/t = rate • Individuals added per unit time = rate of growth

18. BUT, • The growth rate will change in response to other variables • Like what?

19. So, Change in Rate dN/dt

20. So, Change in Rate dN/dt = rN

21. This is compounding dN/dt= rN Because as N gets larger, the constant r multiples by a larger and larger number. As population size (N) increases, the rate of increase gets larger. The result of this compounding is an exponential growth curve. (p 243, 244, 245 Molles; p 67 Kingsolver for examples)

22. PS - Stretch it out • By plotting this same data on a logarithmic scale (10X at each increase), the line straightens out (p 68 Kingsolver)

23. In exponential growth • We can determine the population size at any time (t), by: Nt = N0ert

24. P 244 Molles

25. Can exponential growth continue forever?

26. Can exponential growth continue forever? • Stay tuned for logarithmic (more realistic) growth models (11.2 – 11.3)

27. Lab 4B

28. For Monday • Read Molles 11.2 and 11.3 • Finish AA sheep • Monday is last day to withdraw from full semester courses • Exam 2 is M 3/31 – Ch 9-12 • Five labs left – all field