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Date November 2016 Marks available 3 Reference code 16N.3.HL.TZ0.16
Level Higher level Paper Paper 3 Time zone TZ0 / no time zone
Command term Describe Question number 16 Adapted from N/A

Question

Forest fires are very common in the Amazon forest. A study was performed to see the relationship between forest fragmentation, fire and management

Describe one method that could have been used to estimate the population size of a given tree in a forest after fire damage had occurred.

[3]
a.

Outline how the edge effect can affect diversity in forests.

[3]
b.

The number of plants in two fields of approximately the same size was counted.

Compare and contrast the richness and the evenness of the two fields.

[2]
c.

Markscheme

ALTERNATIVE 1

a. transect through a given area

b. trees counted on transect

c. calculation of total population considering area

ALTERNATIVE 2

d. random sampling using quadrats

e. trees counted in quadrat

f. population calculated using area

ALTERNATIVE 3

g. GPS/Google Earth used to map individuals of a tree species

h. data base of data obtained

i. population density calculated using area

a.

a. edge effect are the changes in community structures that occur at the boundary of two habitats

b. areas with small habitat fragments exhibit especially pronounced edge effects

c. edge species will always have a habitat
OR
edge biodiversity increases

d. if patches of forest are too small the non-edge species cannot find a habitat

e. «then» overall non-edge biodiversity is lower

b.

a. same richness as they have the same number of species/total of individuals

b. field 1 has more evenness as more even distribution of numbers among the species

Accept correct use 2 of Simpson diversity index.

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Option C: Ecology and conservation » Option C: Ecology and conservation (Additional higher level topics) » C.5 Population ecology
Option C: Ecology and conservation » Option C: Ecology and conservation (Additional higher level topics)
Option C: Ecology and conservation

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