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A Level H1 Biology Evolution Diversity Quiz
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Questions
A-Level Biology H1 Quiz - Evolution Diversity
Name: __________________________
Class: __________________________
Date: __________________________
Score: ________ / 45
Duration: 45 minutes
Total Marks: 45
Instructions:
- Answer all questions.
- Write your answers in the spaces provided.
- The number of marks is given in brackets [ ] at the end of each question or part question.
- Use clear scientific terminology.
Section A: Principles of Natural Selection and Variation (Questions 1–5)
1. Define the term variation in the context of a population. [2]
2. Distinguish between continuous and discontinuous variation, giving one biological example for each. [4]
3. Explain why genetic variation is essential for the process of natural selection. [3]
4. State two sources of genetic variation in sexually reproducing organisms. [2]
5. A population of beetles exists in two colors: green and brown. The beetles live on brown tree bark. Birds prey on these beetles.
(a) Identify the selection pressure in this scenario. [1]
(b) Predict how the allele frequency for brown coloration will change over several generations. [2]
Section B: Evidence for Evolution (Questions 6–10)
6. Fig. 1 shows the forelimb bones of a human, a bat, and a whale.
(Note: Imagine a diagram showing homologous structures with similar bone arrangement but different functions)
(a) Name the type of anatomical evidence shown in Fig. 1. [1]
(b) Explain how these structures provide evidence for evolution from a common ancestor. [3]
7. Cytochrome c is a protein involved in cellular respiration. The table below shows the number of amino acid differences in cytochrome c between humans and three other species.
| Species | Amino Acid Differences from Human |
|---|---|
| Chimpanzee | 0 |
| Horse | 12 |
| Yeast | 45 |
(a) Which species is most closely related to humans? [1]
(b) Explain how molecular evidence supports the theory of evolution. [3]
8. Fossils of Archaeopteryx show features of both reptiles (teeth, long bony tail) and birds (feathers, wings).
(a) What term is used to describe fossils that show intermediate characteristics between two groups? [1]
(b) Explain why the fossil record is considered incomplete evidence for evolution. [2]
9. Describe how comparative embryology provides evidence for evolution. [2]
10. Explain why anatomical similarities due to convergent evolution (analogous structures) do not indicate a recent common ancestor. [2]
Section C: Speciation and Classification (Questions 11–15)
11. Define the term species in biological terms. [2]
12. Outline the process of allopatric speciation. [4]
13. Two populations of birds are separated by a mountain range. Over time, they develop different mating calls.
(a) Identify the type of reproductive isolation described. [1]
(b) Explain how this isolation leads to speciation. [2]
14. State the correct order of the following taxonomic ranks from most inclusive to least inclusive:
Family, Genus, Species, Order, Class, Phylum, Kingdom, Domain. [2]
15. Explain why the three-domain system (Archaea, Bacteria, Eukarya) is preferred over the five-kingdom system in modern classification. [2]
Section D: Application and Data Analysis (Questions 16–20)
16. Peppered Moths (Biston betularia) exist in light and dark forms. During the Industrial Revolution, tree trunks became covered in soot.
(a) Explain why the population of dark moths increased during this period. [3]
(b) After clean air legislation was introduced, soot levels decreased. Predict and explain the effect on the moth population. [2]
17. Antibiotic resistance in bacteria is a contemporary example of evolution.
(a) Explain why the overuse of antibiotics accelerates the evolution of resistant strains. [3]
(b) Suggest one strategy to slow down the development of antibiotic resistance. [1]
18. Fig. 2 shows a phylogenetic tree of four species: A, B, C, and D.
(Note: Imagine a tree where A and B share a recent node, C branches off earlier, and D is the outgroup)
(a) Which two species are most closely related? [1]
(b) Explain what the nodes (branching points) in a phylogenetic tree represent. [1]
19. A student claims that "Individual organisms evolve during their lifetime to adapt to their environment."
Refute this statement using the principles of natural selection. [3]
20. Describe the role of geographic isolation in the formation of new species. [3]
End of Quiz
Answers
A-Level Biology H1 Quiz - Evolution Diversity (Answer Key)
1. Define the term variation in the context of a population. [2]
- Differences in characteristics/traits [1]
- Between individuals of the same species/population [1].
2. Distinguish between continuous and discontinuous variation, giving one biological example for each. [4]
- Continuous: Shows a range of values with no distinct categories; usually controlled by polygenic inheritance and environment [1]. Example: Height, mass, skin color [1].
- Discontinuous: Falls into distinct categories with no intermediates; usually controlled by single genes (monogenic) and less influenced by environment [1]. Example: Blood group, tongue rolling, sex [1].
3. Explain why genetic variation is essential for the process of natural selection. [3]
- Provides a range of phenotypes/traits in the population [1].
- Ensures that some individuals possess traits better suited to the environment/selection pressure [1].
- Allows these individuals to survive and reproduce, passing on advantageous alleles [1].
(Note: Without variation, all individuals would be equally affected by selection pressure, preventing evolutionary change.)
4. State two sources of genetic variation in sexually reproducing organisms. [2]
- Mutation (gene mutation or chromosomal mutation) [1].
- Sexual reproduction processes: Random fertilization / Crossing over (meiosis) / Independent assortment (meiosis) [1].
(Accept any two valid sources.)
5. Beetle Scenario:
(a) Selection pressure: Predation by birds [1].
(b) Prediction: The frequency of the brown allele will increase [1]. Brown beetles are better camouflaged, survive predation, and reproduce more successfully, passing the brown allele to offspring [1].
6. Homologous Structures:
(a) Type of evidence: Homologous structures / Comparative anatomy [1].
(b) Explanation:
- The bones have a similar structural arrangement/layout [1].
- But serve different functions (grasping, flying, swimming) [1].
- This suggests they evolved from a common ancestor with this basic limb structure, which was then modified by natural selection for different environments [1].
7. Molecular Evidence:
(a) Most closely related: Chimpanzee [1].
(b) Explanation:
- Closely related species share a more recent common ancestor [1].
- Therefore, there has been less time for mutations to accumulate in their DNA/amino acid sequences [1].
- Fewer differences in sequence indicate closer evolutionary relationship [1].
8. Fossil Evidence:
(a) Term: Transitional fossil / Intermediate fossil [1].
(b) Why incomplete:
- Fossilization is a rare event requiring specific conditions [1].
- Many soft-bodied organisms do not fossilize well / Many fossils have been destroyed by geological activity [1].
9. Comparative Embryology:
- Closely related species show similar stages in early embryonic development [1].
- This suggests they share common genetic instructions inherited from a common ancestor [1].
10. Convergent Evolution:
- Analogous structures arise due to similar selection pressures/environments, not common ancestry [1].
- They have different underlying anatomical structures/embryonic origins despite similar functions [1].
11. Define species. [2]
- A group of organisms [1]
- That can interbreed to produce fertile offspring [1].
12. Outline allopatric speciation. [4]
- A physical/geographic barrier separates a population into two isolated groups [1].
- No gene flow occurs between the groups [1].
- Different selection pressures/mutations act on each group, leading to different allele frequencies [1].
- Over time, reproductive isolation evolves, so they can no longer interbreed even if the barrier is removed [1].
13. Reproductive Isolation:
(a) Type: Behavioral isolation [1].
(b) Explanation:
- Individuals will only mate with those that recognize their specific mating call [1].
- This prevents gene flow between the populations, allowing them to diverge genetically into separate species [1].
14. Taxonomic Ranks Order:
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species [2].
(1 mark for correct relative order of at least 6 ranks; 2 marks for perfect order.)
15. Three-Domain System:
- Based on molecular evidence (rRNA sequences) which shows fundamental differences between Archaea and Bacteria [1].
- Reflects evolutionary relationships more accurately than morphology alone [1].
16. Peppered Moths:
(a) Increase in dark moths:
- Soot darkened the tree trunks, making light moths more visible to predators [1].
- Dark moths were better camouflaged and had higher survival rates [1].
- Dark moths reproduced more, passing the dark allele to the next generation [1].
(b) Effect of clean air: - Tree trunks became lighter (lichen grew back) [1].
- Light moths became better camouflaged, so their population increased while dark moth population decreased [1].
17. Antibiotic Resistance:
(a) Acceleration:
- Bacteria have genetic variation; some possess resistance mutations [1].
- Antibiotics kill non-resistant bacteria, leaving resistant ones to survive (selection pressure) [1].
- Resistant bacteria reproduce rapidly, passing resistance genes to offspring (vertical transmission) or other bacteria (horizontal transmission) [1].
(b) Strategy: - Complete the full course of antibiotics / Do not use antibiotics for viral infections / Rotate antibiotics [1].
18. Phylogenetic Tree:
(a) Most closely related: A and B [1].
(b) Nodes represent: Common ancestors [1].
19. Refuting "Individual Evolution":
- Evolution occurs at the population level over generations, not within an individual's lifetime [1].
- Individuals do not change their genetic makeup in response to the environment; they either possess advantageous alleles or they do not [1].
- Natural selection acts on existing variation, selecting individuals that survive to reproduce [1].
20. Role of Geographic Isolation:
- Prevents gene flow between sub-populations [1].
- Allows each sub-population to accumulate different mutations and adapt to local environmental conditions [1].
- Leads to genetic divergence until reproductive isolation is established [1].