‘AGE: IN MONTHS (BARNACLE) 
0-2 4;6 8,10 i214 41618 290-22 2426 2830 


1000 
1000+ —— 
800 
»| 
600 
400 
200 




= ag 
e 

_NUMBER ALIVE AT START OF EACH AGE __, 
INTERVAL 
= i tien = ion ——— = =—— ~o-- o 2 a 0 a, © SE 
0-1 2-3 4-5 6-7 8-9 10-11 12-13 14-15 
——AGE: INYEARS (SHEEP) OR DAYS (ROTIFER )—— 
Figure 1.--Hypothetical convex curve and 3 survivorship curves which 
tend to approach it (after Deevey) 
R - a rotifers; B - a barnacle; D = Dall sheep 
