Class 9 Biology MCQs: Evolution

MCQs (sample)

Showing 25 questions from this chapter. For a full timed test, use “Start online test”.

1. 1. What is the main process described by the theory of natural selection?

   • Organisms with helpful traits reproduce more effectively.
   • All organisms reproduce at the same rate and survive equally.
   • Genetic mutations occur randomly without impact.
   • Natural selection leads to uniformity in species.
   Answer & explanation

   Correct: Organisms with helpful traits reproduce more effectively.

   Natural selection is the process through which organisms with helpful traits reproduce more effectively, expanding genetic diversity.

2. 2. How many species of living things are currently estimated to exist on Earth?

   • Exceeds a million
   • Less than a million
   • Around five billion
   • Over ten million
   Answer & explanation

   Correct: Exceeds a million

   The text states that the number of species of living things on earth currently exceeds a million.

3. 3. What is speciation?

   • The process by which a single species splits into two or more distinct species.
   • The process of a species becoming extinct.
   • The method by which species adapt to their environments without isolation.
   • The act of one species invading another's habitat.
   Answer & explanation

   Correct: The process by which a single species splits into two or more distinct species.

   Speciation is defined as the process by which a single species splits into two or more distinct species.

4. 4. What offers strong evidence that ancient species were distinct from modern ones?

   • Fossils
   • Genetics
   • Behavioral studies
   • Ecology
   Answer & explanation

   Correct: Fossils

   Fossils provide evidence that ancient species were distinct from modern species as they show evolutionary changes over time.

5. 5. Which factor contributes to the struggle for survival among organisms according to natural selection?

   • Overproduction of offspring.
   • Abundant resources for all individuals.
   • Lack of genetic variations.
   • Uniform environmental conditions.
   Answer & explanation

   Correct: Overproduction of offspring.

   Overproduction refers to the high fertility of organisms leading to a struggle for survival due to limited resources.

6. 6. What does the term 'variation' refer to in biology?

   • Differences in traits displayed by members of the same species
   • The process of evolution
   • The change in species over time
   • The total number of species on Earth
   Answer & explanation

   Correct: Differences in traits displayed by members of the same species

   Variation refers to the differences in traits displayed by members of the same species.

7. 7. What leads to the initial isolation of individuals within a species?

   • Environmental changes like the formation of a river.
   • Increased population size.
   • The introduction of new species.
   • Migration of individuals to other habitats.
   Answer & explanation

   Correct: Environmental changes like the formation of a river.

   Isolation can occur through geographic barriers like the formation of a river.

8. 8. What is the study of similarities and differences in body structures of various organisms called?

   • Comparative anatomy
   • Palaeontology
   • Genetics
   • Ecology
   Answer & explanation

   Correct: Comparative anatomy

   Comparative anatomy examines the similarities and differences in body structures to understand evolutionary relationships.

9. 9. What observation did Charles Darwin make regarding the beaks of finches in the Galapagos Islands?

   • All finches have identical beaks.
   • Beak shapes vary based on food sources.
   • Finches do not adapt to their environment.
   • Beak size is not related to survival.
   Answer & explanation

   Correct: Beak shapes vary based on food sources.

   Darwin observed that the shape of the finches' beaks varied depending on the type of food they consumed.

10. 10. Which of the following is NOT one of the main sources of variation mentioned?

    • Genetic recombination
    • Environmental destruction
    • Fertilization process
    • Mutation in germ cells
    Answer & explanation

    Correct: Environmental destruction

    Environmental destruction is not mentioned as a source of variation; the other options are sources of variation included in the content.

11. 11. Which characteristic develops as isolated groups evolve independently?

    • Similar mating behaviors.
    • Distinct characteristics between groups.
    • Increased genetic similarity.
    • Same food sources.
    Answer & explanation

    Correct: Distinct characteristics between groups.

    As isolated groups evolve, they develop distinct characteristics due to independent evolution.

12. 12. Which structures are shared features inherited from a common ancestor?

    • Homologous structures
    • Vestigial organs
    • Analogous structures
    • Adaptive structures
    Answer & explanation

    Correct: Homologous structures

    Homologous structures are shared features inherited from a common ancestor that can evolve for different functions.

13. 13. What phenomenon explains the increase in dark-coloured peppered moths during the industrial revolution?

    • Natural attraction to pollution.
    • Increased visibility against dark backgrounds.
    • Adaptive advantage due to environmental changes.
    • Decrease in bird populations.
    Answer & explanation

    Correct: Adaptive advantage due to environmental changes.

    The adaptive advantage was due to the darker coloured moths being less visible against dark tree trunks, providing camouflage.

14. 14. What might harmful variations lead to according to the text?

    • Increased survival chances
    • Genetic defects
    • Better reproduction
    • Increased gene flow
    Answer & explanation

    Correct: Genetic defects

    Harmful variations may lead to a genetic defect, making them undesirable.

15. 15. What is a result of reproductive isolation?

    • Groups can interbreed successfully.
    • Fertile offspring can be produced easily.
    • Groups can no longer interbreed.
    • Species remain genetically identical.
    Answer & explanation

    Correct: Groups can no longer interbreed.

    Reproductive isolation means the groups can no longer interbreed successfully.

16. 16. What do vestigial organs signify in organisms?

    • Current functionality
    • Historical features from ancestors
    • Adaptations to the environment
    • Mutational changes
    Answer & explanation

    Correct: Historical features from ancestors

    Vestigial organs are non-functional structures likely remnants from ancestors, indicating historical features.

17. 17. What year did Charles Darwin publish 'On the Origin of Species by Natural Selection'?

    • 1838
    • 1848
    • 1859
    • 1865
    Answer & explanation

    Correct: 1859

    Darwin published his book in 1859, documenting his findings and theory on natural selection.

18. 18. What is one way variation promotes evolution?

    • By creating identical organisms
    • By allowing more progeny for certain individuals
    • By eliminating all genetic changes
    • By decreasing competition among species
    Answer & explanation

    Correct: By allowing more progeny for certain individuals

    Variation promotes evolution by allowing certain individuals with advantageous traits to have more progeny.

19. 19. Which of the following is an example of speciation through geographic isolation?

    • Behavioral differences in mating rituals.
    • Brown bears and polar bears.
    • Intra-species genetic mutation.
    • Increased population density adapting to food sources.
    Answer & explanation

    Correct: Brown bears and polar bears.

    Brown bears and polar bears are examples of speciation due to geographic isolation.

20. 20. How do scientists classify and age fossils?

    • By examining living species
    • By using genetic markers
    • By fossil record comparatives
    • By classifying fossils worldwide
    Answer & explanation

    Correct: By classifying fossils worldwide

    Scientists classify and age fossils from various locations worldwide to understand their evolutionary timeline.

21. 21. What was the primary cause of the dark mutation in peppered moths?

    • Environmental adaptation.
    • Genetic manipulation by humans.
    • Random genetic drift.
    • A direct response to temperature changes.
    Answer & explanation

    Correct: Environmental adaptation.

    The dark coloration in moths resulted from a mutation that provided an adaptive advantage in a polluted environment.

22. 22. An adaptation is defined as:

    • A genetic defect
    • An inherited trait enhancing survival
    • A form of meiosis
    • A type of variation
    Answer & explanation

    Correct: An inherited trait enhancing survival

    An adaptation is an inherited trait or group of traits that increases an organism's chances of survival in specific environmental conditions.

23. 23. What causes genetic differences to accumulate in isolated groups?

    • Population migration.
    • Random events and natural selection.
    • Increased competition.
    • Shared resources among groups.
    Answer & explanation

    Correct: Random events and natural selection.

    Genetic differences accumulate due to gene mutations, random events, and natural selection.

24. 24. Which of the following is an example of a vestigial organ?

    • Human appendix
    • Human arm
    • Bird wing
    • Whale flipper
    Answer & explanation

    Correct: Human appendix

    The human appendix is an example of a vestigial organ that has lost its original function during evolution.

25. 25. Which of the following is NOT one of Darwin's identified patterns in biological diversity?

    • Global diversity
    • Local diversity
    • Variation over time
    • Cultural diversity
    Answer & explanation

    Correct: Cultural diversity

    Cultural diversity is not one of the patterns identified by Darwin in biological diversity.