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Date November 2019 Marks available 2 Reference code 19N.3.HL.TZ0.15
Level Higher level Paper Paper 3 Time zone TZ0 / no time zone
Command term Compare and contrast Question number 15 Adapted from N/A

Question

The table below summarizes the number and percentage of marine species worldwide with at least one documented record of becoming entangled and at least one record of ingesting marine debris, such as plastics and fishing nets.

[Source: Küehn et al. 2015 (http://edepot.wur.nl/344861)]

Compare and contrast the information provided for baleen whales and sea turtles.

[2]
a.

Outline how plastic ingestion may lead to biomagnification in these marine species.

[1]
b.

Describe the use of indicator species in monitoring environmental change.

[3]
c.

Markscheme

a. both show cases of entanglement/ingestion ✔

b. sea turtles similar number of species affected by entanglement/ ingestion while baleen whales more species affected by entanglement than ingestion
OR
higher percentage of sea turtles species affected by entanglement/ ingestion than baleen whales
OR
higher number of species of «baleen» whales than species of sea turtles ✔

Do not accept answers quoting numerical values only.

a.

a. plastic broken down into microplastics to be able to enter the food chain ✔

b. plastic/microplastics become more concentrated at each trophic level ✔ 

Accept descriptions of biomagnification involving any of the species in the table.

b.

a. presence/absence indicate environmental conditions ✔ Accept named environmental condition/pollution.

b. changes in the environment affect these species ✔ Number of species or type of species.

c. «relative» numbers of individuals/indicator species can be used to calculate a biotic index ✔

d. changes monitored over time ✔ Accept example of time frame.

e. changes can lead to measures to protect the environment ✔

f. example of an indicator species AND what it indicates «e.g. Tubifex for sediment pollution» ✔ Award marks for a species, not a group.

c.

Examiners report

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

Syllabus sections

Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics) » C.3 Impacts of humans on ecosystems
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Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics)
Option C: Ecology and conservation

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