Evolution by natural selection — KCSE Biology

KCSE Biology · 81 practice questions · 3 syllabus objectives

28 easy28 medium25 hard

What You'll Learn

Key learning outcomes for this topic, aligned to the KNEC KCSE syllabus.

State Darwin's theory of evolution by natural selection

Give evidence for evolution (fossil record, comparative anatomy)

Evolution by natural selection

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easySHORT ANSWER2 marks

Name two ways in which comparative biochemistry provides evidence for evolution. (2 marks)

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Part (a) — 2 marks

Similarities in DNA sequences among different species, indicating common ancestry (1 mk)

Similarities in protein structures, such as cytochrome c, across diverse organisms (1 mk)

easySHORT ANSWER4 marks

Identify and explain two comparative anatomical features that provide evidence for evolution. (4 marks)

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Part (a) — 4 marks

Homologous structures, such as the forelimbs of mammals, indicating common ancestry (1 mk)

Vestigial organs, like the human appendix, suggesting they were functional in ancestors (1 mk)

Analogous structures, such as wings of bats and insects, showing adaptations to similar environments (1 mk)

Embryonic similarities among vertebrates, reflecting common developmental pathways (1 mk)

easySHORT ANSWER2 marks

Name two types of evidence from the fossil record that support the theory of evolution. (2 marks)

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Part (a) — 2 marks

Transitional fossils, which show intermediate forms between different species (1 mk)

The chronological order of fossils, indicating changes in organisms over time (1 mk)

Explain how the concept of 'survival of the fittest' relates to Darwin's theory of evolution. (4 marks)

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