Evolution

Biology, SSC-Punjab Class 10. This chapter is split into 27 topics and has 638 practice questions. The topics covered are listed below, followed by 10 free sample questions from the chapter.

Topics in this chapter

1. Species and Speciation 26 questions
2. Sources of Variation - Gene Flow and Random Pairing 26 questions
3. Darwin's Observations 26 questions
4. Evidence of Evolution - Comparative Anatomy 26 questions
5. Evidence of Evolution - Fossil Record 26 questions
6. Integrated Review 26 questions
7. Sources of Variation - Mutations and Recombination 26 questions
8. Examples of Natural Selection 26 questions
9. Theory of Natural Selection 26 questions
10. Evidence of Evolution - Selective Breeding 26 questions
11. Darwin Dates and Figures 20 questions
12. Finch Beaks and Adaptation Reasoning 21 questions
13. Natural Selection Step Matching 23 questions
14. Beetle Selection Numerical Examples 21 questions
15. Giraffe and Peppered Moth Steps 22 questions
16. Species and Speciation Scenarios 24 questions
17. Sources of Variation Scenarios 24 questions
18. Mutation and Resistance Reasoning 21 questions
19. Fossil Record Reasoning 22 questions
20. Homologous Analogous and Vestigial Items 24 questions
21. Selective Breeding Details 23 questions
22. Evolution Terms in Context 25 questions
23. True or False in Evolution 24 questions
24. Odd One Out in Evolution 21 questions
25. Evolution Exercise Practice 22 questions
26. Counting Facts in Evolution 21 questions
27. Ordering Steps in Evolution 20 questions

Sample questions: Evolution

10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.

Q1. Considering both the antibiotic resistance example (mutation) and the human sibling example (genetic recombination), which statement best illustrates how both sources of variation contribute differently to a population's genetic diversity?

• A. Mutation introduced a brand-new resistance trait not previously present in the bacterial population, while genetic recombination reshuffled already-existing parental traits into new combinations among human siblings, without creating entirely new traits(correct answer)
• B. Neither example demonstrates any actual contribution to genetic diversity
• C. Genetic recombination created a brand-new trait in bacteria, while mutation reshuffled existing traits in humans
• D. Both examples show mutation and genetic recombination working through the exact same underlying mechanism

Answer: A.The antibiotic resistance example shows mutation introducing a brand-new trait not previously present in the population, while the human sibling example shows genetic recombination reshuffling already-existing parental traits into new combinations, without creating entirely new traits -- illustrating their distinct contributions to genetic diversity.

Q2. Considering all four sources of variation together (mutations, genetic recombination, gene flow, random pairing of gametes), which statement best summarizes how they collectively contribute to the genetic diversity that natural selection can act upon?

• A. Only mutations contribute any variation; the other three sources have no role in genetic diversity
• B. All four sources work through the exact same identical mechanism with no distinction between them
• C. Mutations create entirely new genetic variants, genetic recombination and random pairing of gametes reshuffle existing genes into new combinations within a population, and gene flow introduces genes from other populations -- together providing a broad and continuous supply of variation for natural selection(correct answer)
• D. None of the four sources actually contribute to genetic variation within a population

Answer: C.Mutations create entirely new genetic variants, genetic recombination and random pairing of gametes reshuffle existing genes into new combinations within a population, and gene flow introduces genes from other populations -- together these four sources provide a broad and continuous supply of variation for natural selection to act upon.

Q3. Considering the plant cross-pollination example (gene flow) and the human egg-sperm example (random pairing of gametes) together, which statement best explains why both examples involve the combination of genetic material, yet are classified as distinct sources of variation?

• A. Random pairing of gametes always involves genetic material from a separate population, just like gene flow
• B. In gene flow, the combining genetic material originates from a separate, previously isolated population, while in random pairing of gametes, the combining genetic material comes from within the same interbreeding population, differing in the origin of the genetic material involved(correct answer)
• C. Both examples involve genetic material from the exact same single source with no meaningful distinction
• D. Gene flow never involves any combination of genetic material at all

Answer: B.In gene flow, the combining genetic material originates from a separate, previously isolated population (introducing entirely new genes), while in random pairing of gametes, the combining genetic material comes from within the same interbreeding population -- differing in the origin of the genetic material involved, which is why they are classified as distinct sources of variation.

Q4. Considering homologous structures (arm/leg/flipper/wing) and vestigial structures (appendix/ear muscles/pelvic bones/ostrich wings) together, which statement best summarizes their combined contribution as comparative anatomy evidence for evolution?

• A. Homologous structures show that different species share a common underlying body plan inherited from a shared ancestor, while vestigial structures show that some inherited structures have lost their original function over time -- both patterns are best explained by descent with modification through evolution(correct answer)
• B. Only homologous structures provide any evidence for evolution; vestigial structures are irrelevant
• C. Only vestigial structures provide any evidence for evolution; homologous structures are irrelevant
• D. Homologous and vestigial structures both disprove the theory of evolution by showing unrelated species with no connections

Answer: A.Homologous structures show that different species share a common underlying body plan inherited from a shared ancestor, while vestigial structures show that some inherited structures have lost their original function over time -- both patterns are best explained by descent with modification through evolution, together forming strong comparative anatomy evidence.

Q5. Considering the definition of selective breeding and its relationship to naturally occurring variation, which statement best explains why selective breeding is considered evidence of evolution, even though it involves human intervention?

• A. Selective breeding proves that no heritable variation exists within any population
• B. Selective breeding has no relationship to natural variation or evolutionary principles at all
• C. Selective breeding demonstrates that heritable variation exists within populations and that selecting for certain variations over generations can produce significant changes in a population's characteristics, mirroring the same underlying principles as natural selection(correct answer)
• D. Selective breeding disproves the theory of evolution by natural selection

Answer: C.Selective breeding is considered evidence of evolution because it demonstrates that heritable variation exists within populations and that selecting for certain variations over generations can produce significant changes in a population's characteristics, mirroring the same underlying principles as natural selection, just with humans as the selecting agent.

Q6. Considering all three evidences of evolution described in the chapter (fossil record, comparative anatomy, and selective breeding), which statement best summarizes how they collectively support the overall theory of evolution?

• A. The fossil record shows the historical sequence and transitional forms of past life, comparative anatomy reveals shared ancestry and lost functions through structural similarities, and selective breeding demonstrates that variation and selection can produce significant, observable changes within a species -- together providing multiple independent lines of evidence for evolution(correct answer)
• B. Only selective breeding provides any meaningful evidence for evolution; the other two are irrelevant
• C. All three evidence types disprove the theory of evolution rather than supporting it
• D. The three evidence types are entirely unrelated to each other and to the theory of evolution

Answer: A.The fossil record shows the historical sequence and transitional forms of past life, comparative anatomy reveals shared ancestry and lost functions through structural similarities, and selective breeding demonstrates that variation and selection can produce significant, observable changes within a species -- together these three lines of evidence collectively support the overall theory of evolution.

Q7. Why is variation among individuals important for evolution, integrating the concepts of natural selection, sources of variation, and speciation discussed throughout the chapter?

• A. Variation only matters for selective breeding, not for natural selection or speciation
• B. Evolution can occur even without any variation existing among individuals
• C. Variation provides the raw material that natural selection acts upon; without it, there would be no differences for the environment to favour, no basis for adaptation, and ultimately no pathway for new species to form through processes like allopatric or sympatric speciation(correct answer)
• D. Variation has no relationship to natural selection, adaptation, or speciation

Answer: C.Variation provides the raw material that natural selection acts upon; without it, there would be no differences for the environment to favour, no basis for adaptation, and ultimately no pathway for new species to form through processes like allopatric or sympatric speciation -- making it fundamental to the entire chapter's content.

Q8. Considering the entire chapter's coverage of evolution, which statement best reflects an overall conclusion a student should draw about how life on Earth has diversified over time?

• A. Evolution and speciation are unsupported by any type of scientific evidence
• B. Only human intervention through selective breeding has ever produced new species
• C. Life has diversified through a continuous interplay of heritable variation, environmental (or human-directed) selection pressures, and reproductive isolation, gradually producing the wide range of species observed today and documented in the fossil record and comparative anatomy(correct answer)
• D. Life on Earth has never changed, and all species have existed in their exact current form since the beginning

Answer: C.Life has diversified through a continuous interplay of heritable variation, environmental (or human-directed) selection pressures, and reproductive isolation, gradually producing the wide range of species observed today and documented in the fossil record and comparative anatomy -- the overall conclusion supported by the chapter.

Q9. How does the antibiotic resistance mutation example (from sources of variation) relate to the peppered moth example (natural selection), in terms of the underlying process both illustrate?

• A. The two examples illustrate completely unrelated biological processes with no shared underlying principle
• B. Only the antibiotic resistance example involves any form of selection
• C. Both examples show a population responding to an environmental pressure (antibiotics or predation) by favouring individuals with a pre-existing or newly arisen variation that improves survival, leading to that variation becoming more common over generations(correct answer)
• D. Only the peppered moth example involves any form of variation

Answer: C.Both examples show a population responding to an environmental pressure (antibiotics or predation) by favouring individuals with a pre-existing or newly arisen variation that improves survival, leading to that variation becoming more common over generations -- illustrating the shared underlying principle of natural selection acting on variation.

Q10. A student is asked to design an experiment demonstrating the core principle of natural selection using a population of insects with varying camouflage patterns and a predator. Which key elements from the chapter should the experiment include to accurately represent the process?

• A. Existing variation in camouflage pattern among the insects, exposure to predation creating a struggle for survival, differential survival based on camouflage effectiveness, and reproduction that passes the successful trait to the next generation over multiple generations(correct answer)
• B. The experiment only needs a single insect and no predator at all
• C. The experiment should ensure all insects have identical camouflage patterns before beginning
• D. The experiment should exclude reproduction entirely, since it is irrelevant to natural selection

Answer: A.An accurate experiment should include existing variation in camouflage pattern among the insects, exposure to predation creating a struggle for survival, differential survival based on camouflage effectiveness, and reproduction that passes the successful trait to the next generation over multiple generations -- mirroring the five-step process of natural selection described in the chapter.