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Secondary 4 Combined Science Biology Evolution Diversity Quiz

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Questions

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Secondary 4 Combined Science Biology Quiz - Evolution Diversity

Name: ________________________
Class: ________________________
Date: ________________________
Score: ______ / 40

Duration: 45 minutes
Total Marks: 40

Instructions:

  • Answer ALL questions in the spaces provided.
  • Write your answers clearly and legibly.
  • The number of marks for each question is shown in brackets.
  • Use scientific terminology where appropriate.
  • For calculation questions, show your working.

Section A: Short Answer Questions (10 marks)

Answer all questions in this section.

1. State what is meant by the term "natural selection." [2 marks]

2. Name the scientist who, along with Charles Darwin, independently proposed the theory of evolution by natural selection. [1 mark]

3. Define the term "species." [2 marks]

4. State one source of genetic variation within a population. [1 mark]

5. Explain why antibiotic resistance in bacteria is considered an example of evolution by natural selection. [4 marks]

Section B: Structured Questions (10 marks)

Answer all questions in this section.

6. The diagram below shows the forelimbs of four different vertebrates: a human, a whale, a bat, and a bird.

[Diagram showing forelimb bone structures of human, whale, bat, and bird - all showing similar pentadactyl limb pattern with humerus, radius, ulna, carpals, metacarpals, and phalanges]

(a) Name the type of structure represented by these forelimbs. [1 mark]

(b) Explain how these structures provide evidence for evolution. [3 marks]

(c) The whale forelimb is adapted for swimming, while the bat forelimb is adapted for flying. Explain how structures with a common origin can develop different functions. [2 marks]

7. A population of snails lives in a woodland habitat. The snails show variation in shell colour: some have light-coloured shells, while others have dark-coloured shells. A new predator, a bird species, moves into the woodland and feeds on the snails. The bird can more easily spot light-coloured snails against the dark forest floor.

(a) State the term used to describe the differences in shell colour among the snails. [1 mark]

(b) Using the theory of natural selection, explain what is likely to happen to the snail population over several generations. [2 marks]

(c) Suggest one environmental change that could reverse this trend. [1 mark]

Section C: Data Interpretation Questions (10 marks)

Answer all questions in this section.

8. The table below shows the percentage of a particular bacterial strain resistant to the antibiotic penicillin over a 10-year period in a hospital.

YearPercentage of penicillin-resistant bacteria (%)
20105
201212
201428
201645
201868
202082

(a) Describe the trend shown in the table. [2 marks]

(b) Explain the trend described in (a) using your knowledge of natural selection. [4 marks]

9. The graph below shows the distribution of beak sizes in a population of finches on an island before and after a severe drought.

[Graph showing two bell curves: "Before drought" curve peaks at medium beak size (8-10 mm); "After drought" curve shifts to the right, peaking at larger beak size (11-13 mm). X-axis: Beak size (mm); Y-axis: Number of finches]

(a) Compare the distribution of beak sizes before and after the drought. [2 marks]

(b) During the drought, only large, hard seeds were available as a food source. Explain how this led to the change in beak size distribution shown in the graph. [2 marks]

10. This change in beak size distribution (from Question 9) is an example of evolution. Explain why. [2 marks]

Section D: Extended Response Questions (10 marks)

Answer all questions in this section.

11. The fossil record provides important evidence for evolution. The diagram below shows fossilised bones of an extinct animal.

[Diagram showing a fossil skeleton with a mixture of reptilian and bird-like features: teeth in jaws, long bony tail, wing-like forelimbs with claws, and a keeled sternum]

(a) Suggest why fossils with features of two different groups of organisms are considered strong evidence for evolution. [2 marks]

(b) Explain why the fossil record is incomplete, and state one limitation of using fossils as evidence for evolution. [2 marks]

12. Explain how geographical isolation can lead to the formation of a new species. [4 marks]

13. Compare the processes of artificial selection and natural selection. [2 marks]

14. Explain how comparative embryology provides evidence for evolution. [2 marks]

15. A farmer uses a pesticide to control insect pests on crops. After several years, the pesticide becomes less effective. Explain how this occurred, using the theory of natural selection. [4 marks]

16. Distinguish between convergent evolution and divergent evolution, giving an example of each. [4 marks]

17. Explain how DNA sequencing and molecular biology provide evidence for evolution. [2 marks]

18. Describe how the overuse of antibiotics in agriculture can contribute to the spread of antibiotic resistance in human pathogens. [2 marks]

19. Explain why individuals do not evolve, but populations do. [2 marks]

20. Discuss how both the fossil record and comparative anatomy support the theory of evolution. [4 marks]

END OF QUIZ

Check your answers carefully before submitting.

Answers

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Secondary 4 Combined Science Biology Quiz - Evolution Diversity

ANSWER KEY AND MARKING SCHEME

Total Marks: 40

Section A: Short Answer Questions (10 marks)

1. State what is meant by the term "natural selection." [2 marks]

Answer:

  • The process by which organisms better adapted to their environment / with advantageous traits (1 mark)
  • Are more likely to survive and reproduce, passing on these favourable traits to their offspring (1 mark)

Award:

  • 1 mark for "better adapted / advantageous traits / favourable variations"
  • 1 mark for "survive and reproduce / pass on traits to offspring / differential reproductive success"

2. Name the scientist who, along with Charles Darwin, independently proposed the theory of evolution by natural selection. [1 mark]

Answer: Alfred Russel Wallace

Award: 1 mark for correct name. Accept "Wallace" only.

3. Define the term "species." [2 marks]

Answer:

  • A group of organisms that can interbreed / reproduce with one another (1 mark)
  • To produce fertile offspring (1 mark)

Award:

  • 1 mark for "interbreed / reproduce together"
  • 1 mark for "fertile offspring" (must specify fertile; "offspring" alone is insufficient)

4. State one source of genetic variation within a population. [1 mark]

Answer: Any ONE of the following:

  • Mutation
  • Meiosis / crossing over during meiosis
  • Random fertilisation / sexual reproduction
  • Independent assortment of chromosomes

Award: 1 mark for any valid source.

5. Explain why antibiotic resistance in bacteria is considered an example of evolution by natural selection. [4 marks]

Answer:

  • Within a bacterial population, there is genetic variation; some bacteria possess a mutation / gene that confers resistance to an antibiotic (1 mark)
  • When the antibiotic is applied, non-resistant bacteria are killed (1 mark)
  • Resistant bacteria survive and reproduce (1 mark)
  • The resistance gene is passed to offspring; over generations, the proportion of resistant bacteria in the population increases (1 mark)

Award:

  • 1 mark for identifying pre-existing variation / mutation for resistance
  • 1 mark for selective pressure (antibiotic kills non-resistant bacteria)
  • 1 mark for survival and reproduction of resistant bacteria
  • 1 mark for inheritance of resistance / increase in resistant population over time

Section B: Structured Questions (10 marks)

6. Forelimb structures of vertebrates.

(a) Name the type of structure represented by these forelimbs. [1 mark]

Answer: Homologous structures / homologous organs

Award: 1 mark for "homologous structures" or "homologous organs."

(b) Explain how these structures provide evidence for evolution. [3 marks]

Answer:

  • The forelimbs have a similar basic skeletal structure / pentadactyl limb pattern (same arrangement of bones: humerus, radius, ulna, carpals, metacarpals, phalanges) (1 mark)
  • This similarity suggests that these organisms share a common ancestor (1 mark)
  • The structures have been modified over time through natural selection for different functions (e.g., swimming, flying, grasping), demonstrating divergent evolution / adaptive radiation (1 mark)

Award:

  • 1 mark for identifying similar basic structure / pentadactyl limb
  • 1 mark for linking to common ancestry
  • 1 mark for explaining modification for different functions / divergent evolution

(c) The whale forelimb is adapted for swimming, while the bat forelimb is adapted for flying. Explain how structures with a common origin can develop different functions. [2 marks]

Answer:

  • Organisms with the common ancestral structure faced different environmental pressures / occupied different ecological niches (1 mark)
  • Natural selection favoured different modifications of the basic structure in each lineage, leading to different adaptations / functions over many generations (1 mark)

Award:

  • 1 mark for different environmental pressures / niches
  • 1 mark for natural selection favouring different modifications / adaptations

7. Snail population and predation.

(a) State the term used to describe the differences in shell colour among the snails. [1 mark]

Answer: Variation

Award: 1 mark for "variation" (accept "genetic variation" or "phenotypic variation").

(b) Using the theory of natural selection, explain what is likely to happen to the snail population over several generations. [2 marks]

Answer:

  • There is variation in shell colour within the snail population (light and dark shells) (1 mark)
  • The bird predator can more easily spot light-coloured snails against the dark forest floor, so light-coloured snails are more likely to be eaten (selective pressure) (1 mark)
  • Dark-coloured snails are better camouflaged, so they are more likely to survive and reproduce (differential survival) (1 mark)
  • The dark shell trait is inherited by offspring; over several generations, the proportion of dark-coloured snails in the population will increase (1 mark)

Award:

  • 1 mark for identifying variation
  • 1 mark for selective pressure (predation on light snails)
  • 1 mark for differential survival/reproduction of dark snails
  • 1 mark for inheritance / change in population over generations

(c) Suggest one environmental change that could reverse this trend. [1 mark]

Answer: Any ONE of the following:

  • The forest floor becomes lighter in colour (e.g., due to change in vegetation / leaf litter colour)
  • The bird predator is removed from the habitat
  • A new predator that preferentially targets dark-coloured snails is introduced
  • Change in habitat to lighter-coloured substrate

Award: 1 mark for any plausible environmental change that would favour light-coloured snails.

Section C: Data Interpretation Questions (10 marks)

8. Antibiotic resistance data.

(a) Describe the trend shown in the table. [2 marks]

Answer:

  • The percentage of penicillin-resistant bacteria increased over the 10-year period (1 mark)
  • The increase was from 5% in 2010 to 82% in 2020 / the percentage increased steadily / more than 16-fold increase (1 mark)

Award:

  • 1 mark for identifying increasing trend
  • 1 mark for quoting data to support (start and end values, or describing rate of increase)

(b) Explain the trend described in (a) using your knowledge of natural selection. [4 marks]

Answer:

  • Within the bacterial population, there was genetic variation; some bacteria possessed a gene/mutation conferring resistance to penicillin (1 mark)
  • When penicillin was used in the hospital, it acted as a selective pressure, killing non-resistant bacteria (1 mark)
  • Resistant bacteria survived and reproduced, passing the resistance gene to their offspring (1 mark)
  • Over time (10 years), the proportion of resistant bacteria in the population increased, as shown by the rising percentage in the table (1 mark)

Award:

  • 1 mark for pre-existing variation / resistance gene
  • 1 mark for selective pressure (penicillin kills non-resistant)
  • 1 mark for survival and reproduction of resistant bacteria / inheritance
  • 1 mark for linking to the trend over time

9. Finch beak size distribution.

(a) Compare the distribution of beak sizes before and after the drought. [2 marks]

Answer:

  • Before the drought, the distribution showed a peak at medium beak sizes (8-10 mm) / most finches had medium-sized beaks (1 mark)
  • After the drought, the peak shifted to larger beak sizes (11-13 mm) / the average beak size increased / more finches had larger beaks (1 mark)

Award:

  • 1 mark for describing the "before" distribution (medium peak)
  • 1 mark for describing the "after" distribution (shift to larger beaks)

(b) During the drought, only large, hard seeds were available as a food source. Explain how this led to the change in beak size distribution shown in the graph. [2 marks]

Answer:

  • Finches with larger beaks were better able to crack open and eat the large, hard seeds (1 mark)
  • These finches were more likely to survive the drought and reproduce, passing on their genes for larger beak size to their offspring (1 mark)
  • Over generations, the proportion of finches with larger beaks increased, shifting the distribution to the right (1 mark)

Award:

  • 1 mark for linking larger beaks to survival advantage (access to food)
  • 1 mark for differential reproduction and inheritance / shift in distribution

10. This change in beak size distribution (from Question 9) is an example of evolution. Explain why. [2 marks]

Answer:

  • Evolution is defined as a change in the heritable characteristics of a population over generations (1 mark)
  • The shift in beak size distribution represents a change in the heritable trait (beak size) within the finch population from one generation to the next (1 mark)

Award:

  • 1 mark for definition of evolution (change in heritable traits over generations)
  • 1 mark for applying definition to the finch example

Section D: Extended Response Questions (10 marks)

11. Fossil evidence.

(a) Suggest why fossils with features of two different groups of organisms are considered strong evidence for evolution. [2 marks]

Answer:

  • Such fossils (transitional fossils / intermediate forms) show characteristics of both an ancestral group and a derived group (1 mark)
  • They provide evidence that one group evolved from the other / demonstrate the evolutionary link / common ancestry between the two groups (1 mark)

Award:

  • 1 mark for identifying as transitional fossils / intermediate forms
  • 1 mark for linking to evolutionary relationship / common ancestry

(b) Explain why the fossil record is incomplete, and state one limitation of using fossils as evidence for evolution. [2 marks]

Answer:

  • Why incomplete: Fossilisation requires specific conditions (e.g., rapid burial, hard body parts); most organisms do not fossilise / many fossils are yet to be discovered / geological processes can destroy fossils (1 mark)
  • Limitation: Any ONE of the following:
    • Gaps in the fossil record mean evolutionary pathways are not always clear
    • Fossil record is biased towards organisms with hard body parts
    • Dating fossils can be imprecise
    • Only provides morphological evidence, not behavioural or genetic (1 mark)

Award:

  • 1 mark for valid reason for incompleteness
  • 1 mark for valid limitation

12. Explain how geographical isolation can lead to the formation of a new species. [4 marks]

Answer:

  • A population of a species becomes separated by a geographical barrier (e.g., mountain range, river, ocean) (1 mark)
  • The separated populations experience different environmental conditions / selective pressures (1 mark)
  • Natural selection favours different traits in each population; over many generations, they accumulate different genetic variations (1 mark)
  • Eventually, the populations become so genetically different that they can no longer interbreed to produce fertile offspring, forming a new species (reproductive isolation) (1 mark)

Award:

  • 1 mark for geographical barrier / separation
  • 1 mark for different selective pressures
  • 1 mark for accumulation of genetic differences through natural selection
  • 1 mark for reproductive isolation / formation of new species

13. Compare the processes of artificial selection and natural selection. [2 marks]

Answer:

  • Similarity: Both processes result in changes in the heritable traits of a population over generations / both act on existing variation (1 mark)
  • Difference: In artificial selection, humans select which organisms reproduce based on desired traits; in natural selection, the environment / nature determines which organisms survive and reproduce (1 mark)

Award:

  • 1 mark for valid similarity
  • 1 mark for valid difference

14. Explain how comparative embryology provides evidence for evolution. [2 marks]

Answer:

  • Embryos of different vertebrate species show similar structures / stages in early development (e.g., pharyngeal pouches, post-anal tail) (1 mark)
  • These similarities suggest that these organisms share a common ancestor / common developmental genes (1 mark)

Award:

  • 1 mark for identifying similar embryonic structures/stages
  • 1 mark for linking to common ancestry

15. A farmer uses a pesticide to control insect pests on crops. After several years, the pesticide becomes less effective. Explain how this occurred, using the theory of natural selection. [4 marks]

Answer:

  • Within the insect pest population, there was genetic variation; some insects possessed a gene/mutation that conferred resistance to the pesticide (1 mark)
  • When the pesticide was applied, it acted as a selective pressure, killing susceptible insects (1 mark)
  • Resistant insects survived and reproduced, passing the resistance gene to their offspring (1 mark)
  • Over several years/generations, the proportion of resistant insects in the population increased, making the pesticide less effective (1 mark)

Award:

  • 1 mark for pre-existing variation / resistance gene
  • 1 mark for selective pressure (pesticide kills susceptible)
  • 1 mark for survival and reproduction of resistant insects / inheritance
  • 1 mark for increase in resistant population over time / reduced effectiveness

16. Distinguish between convergent evolution and divergent evolution, giving an example of each. [4 marks]

Answer:

  • Convergent evolution: Unrelated species evolve similar traits independently due to similar environmental pressures / analogous structures (1 mark)
    • Example: Wings of birds and insects / streamlined bodies of dolphins and sharks (1 mark)
  • Divergent evolution: Related species evolve different traits from a common ancestor due to different environmental pressures / homologous structures (1 mark)
    • Example: Pentadactyl limb in vertebrates (human hand, whale flipper, bat wing) / Darwin's finches' beak shapes (1 mark)

Award:

  • 1 mark for definition of convergent evolution
  • 1 mark for valid example of convergent evolution
  • 1 mark for definition of divergent evolution
  • 1 mark for valid example of divergent evolution

17. Explain how DNA sequencing and molecular biology provide evidence for evolution. [2 marks]

Answer:

  • Comparing DNA sequences / amino acid sequences of proteins between different species reveals similarities (1 mark)
  • Species that are more closely related share a higher percentage of similar DNA sequences, indicating common ancestry (1 mark)

Award:

  • 1 mark for comparing DNA/protein sequences
  • 1 mark for linking similarity to evolutionary relatedness / common ancestry

18. Describe how the overuse of antibiotics in agriculture can contribute to the spread of antibiotic resistance in human pathogens. [2 marks]

Answer:

  • Antibiotics used in livestock select for antibiotic-resistant bacteria in the animals (1 mark)
  • These resistant bacteria can be transmitted to humans through the food chain / direct contact / environmental contamination, spreading resistance genes to human pathogens (1 mark)

Award:

  • 1 mark for selection of resistant bacteria in livestock
  • 1 mark for transmission to humans / human pathogens

19. Explain why individuals do not evolve, but populations do. [2 marks]

Answer:

  • An individual's genes / genotype do not change during its lifetime in response to the environment (1 mark)
  • Evolution is defined as a change in the allele frequencies / heritable characteristics of a population over generations (1 mark)

Award:

  • 1 mark for individual's genes not changing
  • 1 mark for evolution occurring at the population level over generations

20. Discuss how both the fossil record and comparative anatomy support the theory of evolution. [4 marks]

Answer:

  • Fossil record:
    • Shows that organisms have changed over time (simple to complex) (1 mark)
    • Provides evidence of transitional forms / extinct species linking different groups (1 mark)
  • Comparative anatomy:
    • Homologous structures (e.g., pentadactyl limb) indicate common ancestry / divergent evolution (1 mark)
    • Analogous structures indicate convergent evolution due to similar environmental pressures (1 mark)
    • Vestigial structures (e.g., human appendix) are remnants of organs that had a function in ancestors (1 mark)

Award:

  • 1 mark for fossil record showing change over time
  • 1 mark for fossil record showing transitional forms
  • 1 mark for comparative anatomy showing homologous structures / common ancestry
  • 1 mark for comparative anatomy showing analogous/vestigial structures (any one valid point)

END OF ANSWER KEY