| Date | May 2011 | Marks available | 2 | Reference code | 11M.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 concept of an ecological niche.
Distinguish between fundamental niches and realized niches.
Markscheme
(ecological niche is) mode of existence/role of an organism within its ecosystem;
(ecological niche includes) its habitat/abiotic factors of the environment;
(ecological niche includes) what the species eats / how the species obtains food;
(ecological niche includes) interactions with other species;
(ecological niche includes) the set of all ranges of limiting factors an organism
tolerates / OWTTE;
fundamental niche is the niche for which a species has adaptations for success/potential mode of existence whereas a realized niche of a species is its actual mode of existence;
the realized niche is often smaller than the fundamental niche (of a species);
competition/predation is reason for the differences (between fundamental and realized niches);
Examiners report
The rest of the option did not cause any great trouble. In G2 (a) most candidates were able to explain the concept of an ecological niche.
Most candidates were able to distinguish between a fundamental and realized niche.
