| Date | November 2020 | Marks available | 2 | Reference code | 20N.1.SL.TZ0.1 |
| Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Explain | Question number | 1 | Adapted from | N/A |
Question
Figure 1(c): Ecosystems of Dominica
[Source: © International Baccalaureate Organization 2020.]
[Source: The Dominica Story: A History of the Island. Lennox Honeychurch ©1995 Macmillan Education.
Reproduced with permission of the Licensor through PLSclear.]
Figure 1(d): Climate graph for Roseau, Dominica
[Source: Adapted from World Weather & Climate Information, Climate and Average Monthly Weather in Roseau, Dominica.
Available at https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,roseau,Dominica.]
Using Figure 1(c), state one ecosystem found at sea level in Dominica.
With reference to Figure 1(d), explain how the environmental conditions on Dominica result in high gross primary productivity.
Markscheme
dry scrub woodland / littoral woodland / seasonal forest;
2000–2500 mm precipitation per year / over 100 mm/high precipitation in every month of the year / high rainfall throughout the year;
…means that water supply is not limiting, allowing for rapid plant growth; warm temperatures consistent all year / mean temperature ranges from 25–28 °C all year;
…contribute to plant growth throughout the year / high rate of photosynthesis
…allows for rapid decomposition of organic matter and rapid nutrient cycling;
Note: Award [1] for the environmental condition, and [1] for relating this to high GPP.
Do not accept “fertile soil” or “tricellular model”.
Do not accept ‘high precipitation/warm temperatures’ without recognition it occurs throughout the year.
Examiners report
The majority of candidates correctly answered this question. However, a number of candidates did not appear to understand the concept of 'sea level'. Incorrect responses included coral reefs, rainforest or naming one of the national parks.
Most responses lacked the necessary detail required to achieve full marks. Candidates frequently did not indicate that high precipitation or warm temperatures occurred throughout the year which allowed for a high rate of photosynthesis resulting in high gross primary productivity.
