Evolution & Natural Selection
Level 1: Recognition
Time limit: 20 minutes | Total marks: 30
Section A — Multiple Choice (choose ONE answer) — 10 marks
Q1. Which of the following provides direct molecular evidence for evolution? (1 mark)
- A) Fossil footprints
- B) Similarity in DNA/amino acid sequences between species
- C) The pentadactyl limb
- D) Vestigial appendix
Q2. Homologous structures are best defined as structures that: (1 mark)
- A) Have the same function but different origin
- B) Have the same evolutionary origin but may differ in function
- C) Are always non-functional
- D) Are found only in unrelated species
Q3. The wings of a butterfly and the wings of a bird are an example of: (1 mark)
- A) Homologous structures
- B) Vestigial structures
- C) Analogous structures
- D) Adaptive radiation
Q4. A vestigial structure is one that: (1 mark)
- A) Is newly evolving and highly useful
- B) Has reduced or lost its original function over evolutionary time
- C) Is identical across all vertebrates
- D) Only appears in fossils
Q5. According to Darwin, natural selection acts on: (1 mark)
- A) Individuals that acquire traits during their lifetime
- B) Heritable variation among individuals in a population
- C) Only the largest organisms
- D) The needs of the species as a whole
Q6. Which type of selection favours the two extreme phenotypes and selects against intermediate forms? (1 mark)
- A) Directional selection
- B) Stabilizing selection
- C) Disruptive selection
- D) Sexual selection
Q7. Peacocks' elaborate tails, which reduce survival but increase mating success, are explained by: (1 mark)
- A) Stabilizing selection
- B) Sexual selection
- C) Artificial selection
- D) Coevolution
Q8. The rapid diversification of Darwin's finches into many species with different beak types is an example of: (1 mark)
- A) Convergent evolution
- B) Adaptive radiation
- C) Coevolution
- D) Vestigiality
Q9. Selective breeding of dogs by humans to produce different breeds is: (1 mark)
- A) Natural selection
- B) Artificial selection
- C) Sexual selection
- D) Disruptive selection
Q10. The reciprocal evolution of a flower's shape and its pollinator's mouthparts is called: (1 mark)
- A) Divergent evolution
- B) Convergent evolution
- C) Coevolution
- D) Adaptive radiation
Section B — Matching — 6 marks
Q11. Match each term in Column X to its correct description in Column Y. (6 marks, 1 each)
| Column X | Column Y |
|---|---|
| (i) Overproduction | (a) Structures with common ancestry, different function |
| (ii) Homologous structures | (b) Two species evolving in response to each other |
| (iii) Analogous structures | (c) More offspring produced than can survive |
| (iv) Coevolution | (d) Unrelated species developing similar traits |
| (v) Convergent evolution | (e) Similar function, independent origin |
| (vi) Divergent evolution | (f) Related species becoming increasingly different |
Section C — True/False WITH Justification — 14 marks
(Each: 1 mark for T/F, 1 mark for justification)
Q12. The presence of similar bone arrangement in a whale flipper and a human arm is evidence of a common ancestor. (2 marks)
Q13. Natural selection requires that variation within a population be heritable to cause evolutionary change. (2 marks)
Q14. Directional selection favours the average (intermediate) phenotype in a population. (2 marks)
Q15. In artificial selection, the environment determines which individuals reproduce. (2 marks)
Q16. Vestigial structures such as the human tailbone provide evidence against evolution. (2 marks)
Q17. Overproduction of offspring combined with limited resources leads to competition (a "struggle for existence"). (2 marks)
Q18. Analogous structures indicate that two species share a recent common ancestor. (2 marks)
Answer keyMark scheme & solutions
Section A (10 marks)
Q1 — B (1): Direct comparison of DNA/amino acid sequences is molecular evidence; the more similar the sequences, the more recent the common ancestor. A/C are anatomical/fossil, D is anatomical.
Q2 — B (1): Homology is defined by shared ancestry (same origin), regardless of current function.
Q3 — C (1): Bird and butterfly wings have similar function (flight) but different evolutionary origins → analogous.
Q4 — B (1): Vestigial = reduced/lost original function inherited from an ancestor.
Q5 — B (1): Selection acts on heritable variation; acquired traits (A) are not inherited.
Q6 — C (1): Disruptive selection favours both extremes and selects against intermediates.
Q7 — B (1): Traits reducing survival but boosting mating success are sexually selected.
Q8 — B (1): One ancestor diversifying rapidly into many niches = adaptive radiation.
Q9 — B (1): Humans doing the selecting = artificial selection.
Q10 — C (1): Reciprocal evolutionary influence between two species = coevolution.
Section B (6 marks)
Q11 (1 each):
- (i) → (c) Overproduction = more offspring than can survive
- (ii) → (a) Homologous = common ancestry, different function
- (iii) → (e) Analogous = similar function, independent origin
- (iv) → (b) Coevolution = species evolving in response to each other
- (v) → (d) Convergent = unrelated species, similar traits
- (vi) → (f) Divergent = related species diverging
Section C (14 marks)
Q12 — TRUE (1). Justification (1): The whale flipper and human arm share the same underlying pentadactyl bone pattern (homologous structure), indicating descent from a common ancestor despite different functions.
Q13 — TRUE (1). Justification (1): Only heritable variation can be passed to offspring; non-heritable variation cannot change allele frequencies across generations, so heritability is essential for evolution by natural selection.
Q14 — FALSE (1). Justification (1): Directional selection favours one extreme phenotype (shifting the mean); it is stabilizing selection that favours the intermediate/average phenotype.
Q15 — FALSE (1). Justification (1): In artificial selection humans (not the environment) choose which individuals reproduce based on desired traits; environmental determination describes natural selection.
Q16 — FALSE (1). Justification (1): Vestigial structures are evidence for evolution — they are reduced remnants of features that were functional in ancestors, showing descent with modification.
Q17 — TRUE (1). Justification (1): Populations produce more offspring than resources can support, so individuals compete for limited resources (struggle for existence), a key premise of Darwin's theory.
Q18 — FALSE (1). Justification (1): Analogous structures arise by convergent evolution in unrelated lineages; they indicate similar selective pressures, not recent common ancestry (that is what homologous structures show).
Marks total: 10 + 6 + 14 = 30
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