1. II. Survivorship

2. A. Definition
1. A survivorship curve shows how likely an individual is to die at a certain age
a. 3 types of populations tend to appear
1. Type I: most deaths at old age
2. Type II: equal deaths at all ages
3. Type III: most deaths at young ages

4. 2. Also can use data to calculate life expectancy which tells length of time an individual can expect to live.
3. Creating a life table collects all pertinent information for an age group.
a. X= age interval
b. D(x)= # of individuals dying
c. S(x)= # of individuals surviving (total individuals –D(x))
d. L(x)= average # of individuals allive [(S(x) + S(x+1))/2]

5. e. T(x)= # of time units for all individuals (years x S Li)
1. goes from bottom up
f. e(x)= life expectancy (T(x)/ S(x))
g. q(x)= age specific mortality rate (fraction dying)
1. q(x)= D(x)/S(x)
h. l(x)= age specific survival (fraction still alive)
1. l(x)= S(x)/S(0)

6. 4. Table should be headed as follows :
Age Class; D(x); S(x); L(x); T(x); e(x); q(x); l(x)

8. 5. Data can be graphed to give big picture
a. Survivorship curves are l(x) vs age class
b. Mortality curves are q(x) vs age class