| Date | November 2013 | Marks available | 4 | Reference code | 13N.3.SL.TZ0.20 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Outline | Question number | 20 | Adapted from | N/A |
Question
State the type of ecological change that will occur following the formation of an island from cooled lava in the Pacific Ocean.
Outline the ecological changes that will occur on the island of cooled lava.
Markscheme
primary succession
soil develops as lava/rock weathers/breaks down/erodes;
organic material/soil accumulates from (autotrophic) bacteria/lichens;
(gross productivity/biomass increase as) small plants are replaced by larger plants;
development of plant communities support higher trophic levels;
more soil allows for detritivores;
succession increases species diversity / climax community established;
Examiners report
Many candidates correctly identified the ecological change occurring as primary succession for 1 mark in (i) but the outline of those ecological changes was very poorly done overall so that few marks were awarded in (ii). Maximum of 2 marks was common.
Many candidates correctly identified the ecological change occurring as primary succession for 1 mark in (i) but the outline of those ecological changes was very poorly done overall so that few marks were awarded in (ii). Maximum of 2 marks was common.
