BILD 3 HW 4. Population ecology. Winter term 2016
Due in section the week of 29 Feb – 4 Mar
(1) How long would it take for a pair of individuals to produce today’s human population
(about 7.1 X 109) at the present rate of population growth (r ≈ 1.98% per year)?
(2) 10 rabbits were introduced onto a small island at the beginning of 1995. One year
later there are 16 rabbits. (a) Assuming that this population is growing geometrically,
how many rabbits will there be in at the beginning of 2005? (b) Again, assuming
geometric growth, what is the doubling time of this population?
(3) The diagram below represents a cohort of 1000 newborn females in an animal
species followed over four years and the number of female offspring produced.
Using the definitions in your text, fill in the following life table information
Age class(x)
sx
lx
bx
0
1
2
3
4
/
/
What is the value of R0?
Assuming that the vital rates (i.e., sx, bx) remain constant, will this population ultimately
increase or decrease as time goes on?
What is the value of the generation time, T?
1
(4) Using the life table values from problem 3, assume that at the start of period t = 0, a
census recorded 100 individuals in each of the first four age classes (0-3). As in the life
table example discussed in lecture, assume that individuals suffer mortality over the
time period, reproduce, and then are counted at the start of the next time period (t=1).
How many individuals would you expect to have in each age group at the start of the
next period (i.e., at t=1)?
census at survival to reproduction
census at
Age class (x)
t=0 end of t= 0
at end of t=0
t=1
0
1
2
3
4
2
