Question 3
In a community, the population of Giraffes and Lions was observed and recorded over time. The result is presented on the graph below. Study it and answer questions3(a) to 3(e).
(a) (i) Name the type of relationship that exists between Giraffes and Lions.[1 mark]
(ii) List five factors that could be responsible for the fluctuation in the number of Lion with time in the community.
[5 marks]
(b) Complete the table
Time (month) |
Number of animals |
|
Giraffe |
Lion |
|
10 |
|
|
20 |
|
|
30 |
|
|
40 |
|
|
50 |
|
|
[5 marks]
(c) Explain briefly the relationship of the populations of Giraffes and Lions as shown in the graph. [3 marks]
(d) What would be the effect of prolonged drought on the community? [3 marks]
(e) If ten Tigers were introduced the community, what would be the effect on the population of Giraffes and Lions?
[3 marks]
Observation
This questionwas well answered by the candidatesthat studied ecology, but it was tough for candidates that could not interpret the graph.Some candidates could not explain the effect of drought on the community as well as the effect of adding another predator to the community.
The candidates that performed well were able to give the number of giraffes and lions in the community, as well as list the factors responsible for the fluctuation in the number of lions with time in the community.
Many candidates could not explain the relationship of the populations of giraffes and lions using the given graph.
The expected answers are:
(a) (i) Relationship between Giraffes and Lions
Predation.
(ii) Factors that could be responsible for thefluctuation in the number of lions in the community
- Competition
- Death rate/mortality
- Migration
- Diseases
- Availability of food
- Birth rate/natality
- Abiotic/environmental factors/conducive environment.
Note: spellings must be correct to score.
(b) Table
Time (Month) |
Number of Animals |
|
Giraffes |
Lions |
|
10 |
120 |
50 |
20 |
160 |
20 |
30 |
140 |
30 |
40 |
120 |
60 |
50 |
140 |
20 |
(c) Relationship between the population of Giraffes and Lions as shown in the Graph
- In this relationship, the giraffes are the prey and the lions are the predators;
- as the population of Lions decreases, the population of giraffes increases;
- as the population of Lions increases, the population of giraffes decreases in the community;
- the relationship is inversely proportional.
(d) Effect of prolonged drought in the Community
- Drought leads to scarcity of water for drinking;
- plants will not grow well/will die, leading to shortage of food;
- Lions and Giraffes will lack drinking water and die;
- this will lead to decrease in the population of giraffes and subsequently the lions;
- then some lions and giraffes will migrate/emigrate.
(e) Effect of introduction of Tigers to the population of Giraffes and Lions in the Community
- Tigers are also predators of giraffes;
- the more tigers and lions in the community, the fewer giraffes there will be;
- and with time, there might be no giraffes left;
- this would lead to less number of lions;
- and competition between the lions and tigers;
- the animals would hunt each other for food;
- and subsequently migration/emigration will occur.