DP Biology (first assessment 2025)

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Question EXEX.2.HL.TZ0.2

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Date Example questions Example questions Marks available [Maximum mark: 7] Reference code EXEX.2.HL.TZ0.2
Level HL Paper 2 Time zone TZ0
Command term Explain, List, Outline Question number 2 Adapted from N/A
2.
[Maximum mark: 7]
EXEX.2.HL.TZ0.2

A decline in the number of species of trees of the Dipterocarpaceae family in some regions of the mixed dipterocarp forest in South-east Asia provides evidence for the present biodiversity crisis.

[Source: Natasha de Vere https://flickr.com/photos/col_and_tasha/5341116968. CC BY 2.0 https://creativecommons.org/licenses/by/2.0/.] 

(a)

List two variables, other than species richness, that can be monitored over time to provide evidence of biodiversity loss in dipterocarp forests.

[2]

Markscheme
  1. area occupied by forest
    OR
    area of forest that has been lost;  
  2. population size/number of individuals of each species/evenness;   
  3. range of a species
    OR
    the area over which a species is found;  
  4. number of threatened species;
(b)

Outline the reason for the loss of dipterocarp forest ecosystems in South Asia.

[2]

Markscheme
  1. anthropogenic reasons / human activities / logging / removal of trees;
  2. to sell timber / grow crops / for plantations / agriculture;
(c)

Thick layers of peat found under dipterocarp forest soils are being lost by rapid decomposition and combustion. Explain how this may contribute to the current biodiversity crisis.

[3]

Markscheme
  1. decomposition/ combustion of peat releases greenhouse gases/ carbon dioxide/ methane;
  2. increased greenhouse effect/ global warming;
  3. changes in climate/ extreme weather/ increasing temperatures/flooding destroy habitats;
  4. species that cannot adapt/migrate are lost;

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