| Date | November 2017 | Marks available | 2 | Reference code | 17N.3.SL.TZ0.12 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Explain | Question number | 12 | Adapted from | N/A |
Question
Calculate the energy loss due to respiration in primary consumers in kJ m–2 y–1.
[1]
a.
Outline why a year is more suitable than a month for the measurement of energy flow.
[1]
b.
Explain how pesticides may undergo biomagnification in the lake.
[2]
c.
Markscheme
190
a.
accounts for different productivity at different times of year/seasonal variations
OR
more data collected
OR
to increase reliability
OR
trends over time more easily detected
b.
a. the increase in concentration of the pesticide at higher trophic levels
b. taken in by organisms low in the food chain
c. cannot be excreted so remains in tissues
OR
accumulates as more organisms from lower levels are eaten
d. pesticides do not degrade/degrade very slowly
[Max 2 Marks]
c.
Examiners report
[N/A]
a.
[N/A]
b.
[N/A]
c.
Syllabus sections
Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics) » C.3 Impacts of humans on ecosystems
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