Friday 3/7
1. Pop Quiz #72. Turtles and Snakes ID Quiz3. Notes on population math from Chs 9 and 104. Lab 4B5. Lab 4A - 15 SP only (for homework)
30 (lab 7) + 20 (PQ 7) + 15 (S&T ID) + (10 wk8Eng)= 75!
Pop Quiz #7
Snakes begins on next slide
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• We’ve talked about (at least) one way to determine if a population is growing
• ?
Rate?
Rate?
• Variable per time
Rate?
• Variable per time• N, t
N/t = rate• Individuals added per unit time = rate of
growth
BUT,
• The growth rate will change in response to other variables
• Like what?
So, Change in Rate
dN/dt
So, Change in Rate
dN/dt
=rN
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)
PS - Stretch it out
• By plotting this same data on a logarithmic scale (10X at each increase), the line straightens out (p 68 Kingsolver)
In exponential growth
• We can determine the population size at any time (t), by:
Nt = N0ert
P 244 Molles
Can exponential growth continue forever?
Can exponential growth continue forever?
• Stay tuned for logarithmic (more realistic) growth models (11.2 – 11.3)
Lab 4B
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
