Imagine that you have been studying the population biology of ground squirrels on the UCSC campus for a number of years and have obtained the following information. A sample of 75 females in 2012 had the age structure shown in column 2 below. Additional longer-term studies of cohort survival and reproduction produced the information on age-specific survival probability [l(x)] and reproduction [b(x)] shown in columns 3 and 4 below.

Age Number of females l(x) Number of births per female [b(x)]

0 25 1.0 0

1 20 0.5 0

2 15 0.4 2

3 10 0.3 2

4 5 0.1 1

5 0

Using these data, answer/make the following questions/calculations.

i. Calculate the values of S(x) from the data in column 2.

ii. Is this similar to that obtained from the cohort analysis of l(x) shown in column 3?

iii. Does the survivorship pattern most closely resemble Type I, II, or III?

iv. Using the data in columns 3 and 4, calculate the net reproductive rate (R0).

v. Is this population stable, increasing, or declining?

vi. Using the data above, project the age structure and size of the population for 2013.

viii. Was the population at a stable age distribution in 2011? Why or why not?