| Date | November 2009 | Marks available | 2 | Reference code | 09N.3.SL.TZ0.20 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Explain | Question number | 20 | Adapted from | N/A |
Question
Outline one example of herbivory.
[2]
a.
State the units used in a pyramid of energy.
[1]
b.
Explain the small biomass of organisms in higher trophic levels.
[2]
c.
Markscheme
named example of herbivore;
named example of plant;
e.g. aphid
rose
a.
kJ m-2 yr-1 / kilojoules per meter squared per year / example of energy per unit area per time unit (must be metric units)
b.
much loss of energy / 10/20 % retained / 80/90 % loss of energy;
respiration;
egestion;
less valuable as a food source than primary producers;
c.
Examiners report
Most candidates could state an example of a herbivore and the plant it fed on.
a.
This was often not answered well.
b.
Some candidates mentioned the energy loss from one trophic level to the next. Few explained what caused this loss.
c.
Syllabus sections
Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics) » C.2 Communities and ecosystems
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