| Date | November 2014 | Marks available | 3 | Reference code | 14N.1.SL.TZ0.4 |
| Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Describe | Question number | 4 | Adapted from | N/A |
Question
Define the term biome.
Describe how biomass data from a named biome could be collected.
Markscheme
set of similar ecosystems with the same climatic conditions that determine the climax vegetation that can grow there; OWTTE
[1 max]
Named biome: tundra/tropical rainforest/desert. [2 max] if no biome is named.
large quadrats to include largest vegetation of area;
stratified sampling so all ecosystems in the biome are sampled / use of random sampling method;
capture and take mass of all organisms in quadrat;
take wet mass and convert to dry mass using representative data if available;
dry samples to obtain biomass;
use average calculated value of biomass per quadrat to extrapolate to represent whole area;
samples taken at different seasons;
representative samples are dug up for vegetation;
use conversion tables to determine tree biomass/height and circumference data used; OWTTE
[3 max]
Examiners report
The majority of candidates provided a clear definition of ‘biome’. Common error was to omit ‘collection of ecosystems’.
Few candidates achieved full marks for this. Most answers were too vague with regards to how samples were collected and how the representative biomass data collected could then be extrapolated to the area. There were a significant number of blank responses or description of Lincoln Index given.
Syllabus sections
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18M.2.SL.TZ0.5b:
Suggest the procedures needed to collect data for the construction of a pyramid of numbers for the following food chain:
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15N.1.SL.TZ0.2a.i:
Calculate the Simpson’s diversity index for the insect species found in Figure 1.
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16N.2.SL.TZ0.3b:
Describe two possible methods that could be used to collect data for a baseline study for an environmental impact assessment.
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16N.1.SL.TZ0.3b:
Describe a method for measuring the abundance of plant species in volcanic areas.
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17N.1.SL.TZ0.5c:
Identify two reasons why the future size of the Atlantic puffin population is difficult to predict.
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19N.2.SL.TZ0.6b:
Explain how ecological techniques can be used to study the effects of human activities on the biodiversity of a named ecosystem.
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19N.1.SL.TZ0.4c:
With reference to Figures 10, 11(a) and 11(b), describe a method to monitor the impact of the release of untreated sewage into the St Lawrence River ecosystem.
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16M.1.SL.TZ0.1c:
Avocets, seen in Figure 2, often gather in large populations of up to a few thousand birds before migrating.
Figure 2
[Source: https://en.wikipedia.org/wiki/Pied_avocet#/media/File:Avocet_from_the_Crossley_ID_
Guide_Britain_and_Ireland.jpg, by Richard Crossley — The Crossley ID Guide Britain and Ireland]
Describe a method to estimate the size of an avocet population. - 18N.1.SL.TZ0.6: Suggest how an ecologist might measure the changes in one abiotic factor along a transect...
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14M.1.SL.TZ0.3a.i:
Identify one method that may have been used to estimate the size of this gorilla population.
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15N.1.SL.TZ0.2b.ii:
Describe a method measuring changes in the abiotic factor you have identified in 2(b)(i).
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15N.1.SL.TZ0.1b:
Describe how the biomass of a field of crops might be measured.
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16M.2.SL.TZ0.4b:
A non-governmental organization has been contracted to investigate the impacts of a landfill site on the surrounding terrestrial ecosystem.
Suggest how the investigation should be designed to ensure reliability and validity.
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18N.1.SL.TZ0.10b:
The number of wolves in Algonquin Provincial Park is estimated to be between 250 and 1000. Outline two reasons why it is so difficult to estimate the number of wolves accurately.
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17M.2.SL.TZ0.4b:
Suggest a series of procedures that could be used to estimate the net productivity of an insect population in kg m–2 yr–1.
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16N.2.SL.TZ0.1e:
With reference to the data in Figure 4(b), suggest two conclusions which can be drawn from the camera trap data.
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14M.2.SL.TZ0.2a.ii:
Identify the data required to calculate the value of net secondary productivity for a named population.
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15N.1.SL.TZ0.2a.ii:
Identify two possible reasons why species B and C were not present in the litter layer when it was resampled six months later.
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17N.2.SL.TZ0.2b:
Figure 3: Table to show the species richness of Yasuni National Park
[Source: Margot S. Bass, Matt Finer, Clinton N. Jenkins, Holger Kreft, Diego F. Cisneros-Heredia, Shawn F. McCracken,
Nigel C. A. Pitman, Peter H. English, Kelly Swing, Gorky Villa, Anthony Di Fiore, Christian C. Voigt and Thomas H. Kunz,
‘Global Conservation Significance of Ecuador’s Yasuní National Park.’ PLoS One, January 19, 2010.
https://doi.org/10.1371/journal.pone.0008767]Describe a method that may have been used for collecting the tree data in Figure 3.
