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

Question

Describe what is shown in a cladogram.

[2]
a.

Outline how variation in organisms of the same species could lead to natural selection.

[3]
b.

Markscheme

a. similarities/differences between organisms/species/clades ✔ mpa and mpd concern actual characteristics, not evolutionary relationships.

b. «probable» evolutionary relationships/closeness/common ancestry/phylogeny ✔ mpb concerns such relationships

c. divergence/splits/speciation/branches/nodes ✔ mpc concerns the structure branching of the cladogram

d. relative similarity/differences between base sequence/amino acid sequence ✔

a.

a. survival of the better adapted/fittest ✔

b. more reproduction of better adapted/fittest/individuals with favorable variations ✔

c. genes for favorable variations/adaptations passed on to offspring ✔ Accept answers in the converse.

d. competition for resources/more offspring produced than the environment can support/a struggle for existence ✔ Accept answers in the converse.

b.

Examiners report

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

Syllabus sections

Core » Topic 5: Evolution and biodiversity » 5.2 Natural selection
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Core » Topic 5: Evolution and biodiversity
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