Population Growth Questions Answer Key - Bates Page 4
ADVERTISEMENT
1
2
3
4Bio 270 Practice Population Growth Questions
8. What are the effects of environmental and demographic stochasticity on population
growth?
Environmental and demographic stochasticity will result in variation in the population growth
rate. Under these influences population size will fluctuate significantly over time.
9. A sample of single celled marine algae from the Giant Stairs site provided an estimate of
100,000 cells on the initial sampling date. Ten days later, the population size was
estimated to be 500,000 cells. Calculate the intrinsic rate of increase (r) for the population.
rt
N
= N
e
t
o
rt
N
/ N
= e
t
o
Take the natural log of both sides to get rid of e-
ln N
- ln N
= rt
t
o
ln N
- ln N
/t = r
t
o
Plug in the numbers….
r = ln(500,000) - ln(100,000)/10 = 13.12 - 11.51/10 = 0.16 indiv./(indiv. x day)
10. For the algal population described in question 9 above, use the exponential model of
population growth to predict the size of the population after another 10 days.
rt
N
= N
e
t
o
We're given this info:
N
= 500,000
t = 10 days
r = 0.16
o
rt
N
/ N
= e
t
o
(.16)(10)
N
/500,000 = e
t
ln N
- ln (500,000) = 1.6
t
ln N
= 13.12 + 1.6
t
ln N
= 14.72
t
N
= 2.47 million cells
t
4
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education