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Question 20N.3.SL.TZ0.13

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Date November 2020 Marks available [Maximum mark: 5] Reference code 20N.3.SL.TZ0.13
Level SL Paper 3 Time zone TZ0
Command term Calculate, Describe, Identify, Suggest Question number 13 Adapted from N/A
13.
[Maximum mark: 5]
20N.3.SL.TZ0.13

Plastic has accumulated in marine environments and is now causing problems for wildlife. Some marine birds have become entangled in plastic debris and some have been harmed by ingesting it. The table shows the extent of the problem worldwide in different groups of birds.

[Source: BIO Intelligence Service, 2011. Plastic Waste in the Environment. [pdf]
European Commission. Available at: http://ec.europa.eu/environment/waste/studies/pdf/plastics.pdf.]

(a.i)

Calculate the number of species of grebe with problems due to entanglement.

[1]

Markscheme

2;

Examiners report

This question outlining how plastic pollution affects marine birds was straightforward for all candidates.

(a.ii)

Suggest how entanglement in plastics can lead to the death of marine birds.

[1]

Markscheme

a. birds are unable to fly/swim for food;

b. unable to escape predators;

c. birds drown;

d. birds suffocate / are strangled;

(b.i)

Identify the group with the greatest number of species with problems due to ingestion of plastics.

[1]

Markscheme

C / albatrosses, petrels and shearwaters;

(b.ii)

Describe how ingested plastics can cause problems to marine birds.

[2]

Markscheme

a. fill up the stomachs (of young birds) so they feel full / starve to death;

b. damage the digestive system / cut the gut/stomach/oesophagus/intestines (leading to internal bleeding);

c. block passage of food (causing starvation);

d. cause choking (so cannot breathe);

e. contain/decompose to toxic chemicals (poisoning birds)
OR
toxins/microplastics in seawater build up/biomagnify (and poison wildlife);

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