Question

The data provided represents populations of a predator and its prey over a fifty years periods.

Time in years	Population in relative population of P (in thousands)	Numbers population of Q (in thousands)
5  10  15  20  25  30  35  40  45  50	24.5  30  33.5  33.5  31  27  25  29  32.5  34	17  20.5  26  30  33  32  30  27.5  28.0  28.5

1. Using the same axes, draw graphs of the relative populations of P and Q against time. 
2. With a reason identify the curve that represents the prey. 
3. Accounts for the two populations between 25 and 32 years. 
4. Which years were the two populations equal. 
5. Apart from predation, state three biotic factors that may have led to the decline of the prey population.

Answer 1

1. 
   
2. Curve P – increase in population of P leads to increase in population of Q. They provide plenty of food.
3. Both organisms are declining with time. Population of P is declining sharply due to a higher rate of predation, since number of predators is high. Q is declining due to stiff competition for food.
4. 23rd and 39th.
5.  
   1. Parasitism
   2. pest and diseases
   3. competition
   4. human activities