| Date | November 2011 | Marks available | 2 | Reference code | 11N.2.SL.TZ0.3 |
| Level | Standard level | Paper | Paper 2 | Time zone | TZ0 |
| Command term | Construct | Question number | 3 | Adapted from | N/A |
Question
The diagrams below show different organisms (not drawn to scale).
State all the organisms shown above that belong to the following phyla.
Filicinophyta:
Arthropoda:
Mollusca:
Construct a possible food chain using three of the organisms shown opposite, stating the trophic level to which they belong.
State the initial energy source of the food chain constructed in (b)(i).
Markscheme
filicinophyta: fern;
arthropoda: spider, ant, crab; (all three needed to award the mark)
mollusca: snail;
e.g.
daisy/fern → ant → spider;
daisy/fern → snail → crab/sea lion/ant;
producer primary consumer secondary consumer;
Award [1 max] for correct trophic levels. Award [1] for the correct sequence of organisms which includes a producer.
sun / solar energy/light
Examiners report
Widespread weakness was seen as many candidates could not identify which organisms belonged to which phyla (A.S. 5.5.3, 5.5.4). One correctly matched organism was often mixed with one that didn't belong, resulting in no mark.
Unrealistic food chains were given; for example, daisy→ant→snail. Arrows showing energy flow did not always lead from producer to primary consumer etc. or were shown leading in both directions. Finally, the food chain had to include a producer, a primary consumer and a secondary consumer.
Although the food chain in 3(b)(i) had to begin with either daisy or fern, the initial source of energy should have been (sun)light. Either plant was unacceptable for the mark.
