| Date | May 2013 | Marks available | 3 | Reference code | 13M.3.SL.TZ2.20 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Explain | Question number | 20 | Adapted from | N/A |
Question
Explain the niche concept.
Outline one reason for the extinction of a named animal species
Markscheme
a. niche is an organism’s ecological role/mode of existence;
b. niche is how organism uses abiotic and biotic resources;
c. depends on where organism lives/habitat;
d. depends on organism’s nutrition/feeding activities;
e. depends on interactions (competition/herbivory/predation/mutualism) with other organisms;
name of species and what caused it to become extinct (both needed)
The named species must be extinct and not endangered.
eg:
passenger pigeon (became extinct when) hunted as a source of food
Note: dinosaur is not a named species.
Examiners report
Most of the better candidates could explain the niche concept. Weaker candidates who attempted this part complicated matters by trying to write at length on fundamental and realised niches.
Part c caused several comments from teachers as they were quite correct that it could be construed as a HL question. The markscheme was constructed to incorporate the SL coverage (AS G.3.5), while still allowing for a HL answer (from AS G.4.2) resulting in many students achieving the mark. However a significant number did not mention a named species as instructed, so immediately lost the mark.
