ROUTERA


Chapter 7 Evolution

Class 12th Biology Chapter MCQs


1. What is the basic concept of evolution according to Darwin's theory?

  • A) Inheritance of acquired traits
  • B) Survival of the fittest
  • C) Natural selection
  • D) Genetic drift

Answer: C
Explanation: Darwin’s theory of evolution is based on the concept of natural selection, where organisms better suited to their environment are more likely to survive and reproduce.


2. Which of the following is NOT a mechanism of evolution?

  • A) Mutation
  • B) Gene flow
  • C) Genetic drift
  • D) Fertilization

Answer: D
Explanation: Fertilization is not a mechanism of evolution; it is a process in reproduction. Evolutionary mechanisms include mutation, gene flow, and genetic drift.


3. The molecular evidence supporting the theory of evolution is based on:

  • A) Fossil records
  • B) Comparative anatomy
  • C) Comparative embryology
  • D) Comparative biochemistry

Answer: D
Explanation: Comparative biochemistry, such as comparing the DNA and protein sequences of different species, provides molecular evidence for evolution.


4. Which of the following is an example of divergent evolution?

  • A) Wings of bats and birds
  • B) Human forelimbs and whale forelimbs
  • C) Wings of bats and insects
  • D) Eyes of octopus and humans

Answer: B
Explanation: Divergent evolution refers to the evolution of different structures in related species due to different environmental pressures. Human and whale forelimbs share a common ancestral structure but have evolved differently.


5. The earliest primate-like mammal that appeared during the Mesozoic era was:

  • A) Australopithecus
  • B) Homo erectus
  • C) Plesiadapis
  • D) Homo sapiens

Answer: C
Explanation: Plesiadapis is one of the earliest known primate-like mammals from the Mesozoic era and is considered a precursor to modern primates.


6. Which of the following is an example of convergent evolution?

  • A) Wings of bats and birds
  • B) Limbs of amphibians and reptiles
  • C) Tail of fish and mammals
  • D) Eyes of octopus and humans

Answer: D
Explanation: Convergent evolution occurs when unrelated species evolve similar traits due to similar environmental pressures. The eyes of octopus and humans are examples of convergent evolution.


7. The Hardy-Weinberg equilibrium principle assumes that:

  • A) There is no mutation
  • B) There is a large population size
  • C) There is random mating
  • D) All of the above

Answer: D
Explanation: The Hardy-Weinberg equilibrium assumes no mutation, random mating, large population size, no natural selection, and no gene flow.


8. Which of the following is a characteristic of genetic drift?

  • A) It occurs more rapidly in small populations
  • B) It is a form of natural selection
  • C) It leads to adaptation of organisms to their environment
  • D) It always increases genetic variation

Answer: A
Explanation: Genetic drift refers to random changes in allele frequencies, which are more pronounced in small populations.


9. What is a vestigial organ?

  • A) An organ that performs a useful function in one species
  • B) An organ that is a remnant of an ancestral organ that no longer has a function
  • C) An organ that is homologous in structure
  • D) An organ that is present in all species

Answer: B
Explanation: A vestigial organ is an organ that has lost its original function but remains present in the body, such as the human appendix.


10. The process of natural selection involves:

  • A) Survival of the strongest individuals
  • B) Random mating of organisms
  • C) Accumulation of beneficial traits in a population
  • D) Random genetic mutations

Answer: C
Explanation: Natural selection involves the accumulation of beneficial traits in a population that increase an organism’s chances of survival and reproduction.


11. Which of the following best explains the concept of "fitness" in evolutionary terms?

  • A) Physical strength
  • B) Ability to survive and reproduce
  • C) Genetic diversity
  • D) Speed of adaptation

Answer: B
Explanation: In evolutionary terms, fitness refers to an organism’s ability to survive, reproduce, and pass on its genes to the next generation.


12. Which of the following types of evidence supports the theory of evolution?

  • A) Comparative embryology
  • B) Fossil records
  • C) Comparative anatomy
  • D) All of the above

Answer: D
Explanation: Fossil records, comparative anatomy, and comparative embryology all provide evidence that supports the theory of evolution.


13. Which of the following can lead to the formation of new species?

  • A) Genetic drift
  • B) Natural selection
  • C) Geographic isolation
  • D) All of the above

Answer: D
Explanation: Genetic drift, natural selection, and geographic isolation are all mechanisms that can lead to the formation of new species.


14. The concept of "inheritance of acquired characteristics" was proposed by:

  • A) Charles Darwin
  • B) Jean-Baptiste Lamarck
  • C) Gregor Mendel
  • D) Alfred Wallace

Answer: B
Explanation: Jean-Baptiste Lamarck proposed the idea of the inheritance of acquired characteristics, which was later replaced by Darwin’s theory of natural selection.


15. Which of the following is an example of artificial selection?

  • A) The development of antibiotic resistance in bacteria
  • B) The selective breeding of dogs
  • C) The adaptation of organisms to new environments
  • D) The formation of new species

Answer: B
Explanation: Artificial selection is the process by which humans selectively breed plants or animals with desired traits, such as in the breeding of dogs.


16. Which of the following is an example of homologous structures?

  • A) Wings of bats and birds
  • B) Flippers of dolphins and fins of fish
  • C) Forelimbs of humans and cats
  • D) Eyes of octopus and humans

Answer: C
Explanation: Homologous structures are similar in structure but may have different functions, as seen in the forelimbs of humans and cats.


17. Which of the following provides the best evidence for evolution?

  • A) Fossil records
  • B) Observed mutations in bacteria
  • C) Comparative studies of DNA sequences
  • D) All of the above

Answer: D
Explanation: Fossil records, observed mutations, and DNA sequence comparisons all provide significant evidence for evolution.


18. What is the term used to describe the process by which new species evolve from a common ancestor?

  • A) Speciation
  • B) Mutation
  • C) Adaptation
  • D) Homologous evolution

Answer: A
Explanation: Speciation is the process through which new species evolve from a common ancestor.


19. Which of the following is an example of adaptive radiation?

  • A) The evolution of different finch species on the Galápagos Islands
  • B) The development of human and chimpanzee species from a common ancestor
  • C) The spread of antibiotic resistance in bacteria
  • D) The formation of a new species through geographic isolation

Answer: A
Explanation: Adaptive radiation is the rapid evolution of many species from a single ancestral species, as seen in the finches of the Galápagos Islands.


20. The theory of punctuated equilibrium suggests that:

  • A) Evolution occurs slowly and steadily over time
  • B) Evolution occurs in rapid bursts followed by long periods of stability
  • C) Species evolve due to gradual accumulation of genetic changes
  • D) Evolutionary change is always gradual

Answer: B
Explanation: Punctuated equilibrium proposes that species remain stable for long periods, with short bursts of rapid evolutionary change.


21. Which of the following is an example of coevolution?

  • A) The mutualistic relationship between flowering plants and their pollinators
  • B) The adaptation of animals to different climates
  • C) The development of antibiotic resistance in bacteria
  • D) The variation in beak sizes of finches

Answer: A
Explanation: Coevolution is the process by which two species evolve in response to each other, such as the relationship between flowering plants and their pollinators.


22. What does the bottleneck effect refer to?

  • A) The process by which a small population colonizes a new habitat
  • B) A dramatic reduction in population size due to environmental events
  • C) The increase in genetic variation in a population
  • D) The gradual accumulation of mutations

Answer: B
Explanation: The bottleneck effect refers to a drastic reduction in population size due to an environmental event, leading to a loss of genetic diversity.


23. Which of the following is the primary factor leading to natural selection?

  • A) Environmental changes
  • B) Random mutations
  • C) Organisms competing for resources
  • D) All of the above

Answer: D
Explanation: Natural selection is driven by environmental changes, random mutations, and competition for resources, leading to the survival of the fittest.


24. Which of the following is an example of directional selection?

  • A) The increase in the frequency of dark moths in industrial areas
  • B) The maintenance of average traits in a population
  • C) The development of antibiotic-resistant bacteria
  • D) The formation of different beak sizes in a finch population

Answer: A
Explanation: Directional selection favors one extreme phenotype, such as the increase in dark-colored moths in polluted areas.


25. Which of the following is the correct sequence of evolutionary events?

  • A) Mutation → Natural selection → Speciation
  • B) Speciation → Natural selection → Mutation
  • C) Natural selection → Speciation → Mutation
  • D) Mutation → Speciation → Natural selection

Answer: A
Explanation: Mutation introduces genetic variation, which is acted upon by natural selection, leading to speciation.


26. Which of the following is an example of stabilizing selection?

  • A) The increase in dark moths in industrial areas
  • B) The maintenance of a specific body size in a species
  • C) The formation of new species through geographic isolation
  • D) The evolution of antibiotic resistance in bacteria

Answer: B
Explanation: Stabilizing selection favors the average phenotype in a population, maintaining a specific body size within a species.


27. Which of the following is true about the founder effect?

  • A) It occurs when a small group of individuals establishes a new population
  • B) It is a form of genetic drift
  • C) It can lead to a reduction in genetic diversity
  • D) All of the above

Answer: D
Explanation: The founder effect is a type of genetic drift that occurs when a small group of individuals establishes a new population, leading to reduced genetic diversity.


28. The study of fossils helps to:

  • A) Understand the evolutionary history of organisms
  • B) Study the behavioral traits of ancient species
  • C) Identify the molecular evidence for evolution
  • D) All of the above

Answer: A
Explanation: Fossil records provide information about the evolutionary history of organisms and help trace the lineage of different species.


29. Which of the following is the cause of variation within a population?

  • A) Sexual reproduction
  • B) Mutation
  • C) Gene flow
  • D) All of the above

Answer: D
Explanation: Sexual reproduction, mutation, and gene flow all contribute to genetic variation within a population.


30. The concept of "survival of the fittest" refers to:

  • A) The strongest organisms surviving
  • B) The most genetically diverse organisms surviving
  • C) The organisms best adapted to their environment surviving and reproducing
  • D) The organisms with the greatest number of offspring surviving

Answer: C
Explanation: Survival of the fittest refers to the organisms that are best suited to their environment and can reproduce successfully.


31. Which of the following supports the idea of common ancestry?

  • A) Homologous structures
  • B) Vestigial organs
  • C) Fossil records
  • D) All of the above

Answer: D
Explanation: Homologous structures, vestigial organs, and fossil records all provide evidence for the idea of common ancestry among different species.


32. Which of the following terms describes a group of individuals of the same species living in a specific area?

  • A) Population
  • B) Species
  • C) Ecosystem
  • D) Community

Answer: A
Explanation: A population refers to a group of individuals of the same species living in a specific geographic area.


33. Which of the following processes can result in adaptive evolution?

  • A) Genetic drift
  • B) Natural selection
  • C) Mutation
  • D) Gene flow

Answer: B
Explanation: Natural selection results in adaptive evolution, where beneficial traits become more common in a population.


34. The founder effect is most likely to occur when:

  • A) A small group of individuals moves to a new area
  • B) A large population undergoes a genetic mutation
  • C) There is a sudden environmental change
  • D) There is genetic drift in a large population

Answer: A
Explanation: The founder effect occurs when a small group of individuals colonizes a new area, leading to reduced genetic diversity.


35. Which of the following terms is used for the gradual change of organisms over time?

  • A) Speciation
  • B) Mutation
  • C) Evolution
  • D) Gene flow

Answer: C
Explanation: Evolution refers to the gradual change in organisms over time due to genetic changes.


36. Which of the following is a source of genetic variation in populations?

  • A) Mutation
  • B) Sexual reproduction
  • C) Genetic recombination
  • D) All of the above

Answer: D
Explanation: Mutation, sexual reproduction, and genetic recombination are all sources of genetic variation in populations.


37. Which of the following is an example of microevolution?

  • A) The development of a new species
  • B) The change in allele frequency within a population
  • C) The adaptation of organisms to a new environment
  • D) The extinction of a species

Answer: B
Explanation: Microevolution refers to changes in allele frequencies within a population over time, leading to small-scale evolutionary changes.


38. Which of the following is NOT a type of natural selection?

  • A) Directional selection
  • B) Disruptive selection
  • C) Stabilizing selection
  • D) Sexual selection

Answer: D
Explanation: Sexual selection is not considered a type of natural selection, though it is related to evolutionary processes.


39. Which of the following mechanisms of evolution leads to random changes in allele frequencies?

  • A) Natural selection
  • B) Mutation
  • C) Genetic drift
  • D) Gene flow

Answer: C
Explanation: Genetic drift leads to random changes in allele frequencies, particularly in small populations.


40. Which of the following is true about adaptive evolution?

  • A) It occurs in response to changes in the environment
  • B) It leads to the formation of new species
  • C) It is driven by natural selection
  • D) All of the above

Answer: D
Explanation: Adaptive evolution occurs in response to environmental changes, is driven by natural selection, and can lead to the formation of new species.


41. Which of the following is an example of gene flow?

  • A) A population of beetles changing color due to natural selection
  • B) A group of organisms migrating and interbreeding with a new population
  • C) A population becoming smaller due to a bottleneck effect
  • D) A species adapting to its environment over time

Answer: B
Explanation: Gene flow occurs when individuals from different populations interbreed, transferring genetic material between populations.


42. Which of the following mechanisms results in genetic variation?

  • A) Genetic drift
  • B) Gene flow
  • C) Mutation
  • D) All of the above

Answer: D
Explanation: Genetic drift, gene flow, and mutation all contribute to genetic variation in a population.


43. Which of the following is a true statement about evolution?

  • A) Evolution always results in the formation of new species
  • B) Evolution is a gradual process that occurs over millions of years
  • C) Evolution occurs only in large populations
  • D) Evolution is driven solely by genetic mutations

Answer: B
Explanation: Evolution is a gradual process that occurs over long periods of time, often over millions of years.


44. Which of the following is an example of a vestigial structure?

  • A) Human tailbone
  • B) Eyes of blind fish
  • C) Wings of birds
  • D) The large teeth of carnivores

Answer: A
Explanation: The human tailbone is a vestigial structure, a remnant of a tail that was present in ancestral species.


45. Which of the following is true about natural selection?

  • A) It leads to the elimination of all genetic variation
  • B) It is the sole mechanism of evolution
  • C) It results in organisms that are best suited to their environment
  • D) It always results in the formation of new species

Answer: C
Explanation: Natural selection results in organisms that are better adapted to their environment, increasing their chances of survival and reproduction.


46. Which of the following describes a population of organisms living in different geographic areas but belonging to the same species?

  • A) Allopatric populations
  • B) Sympatric populations
  • C) Speciation
  • D) Clade

Answer: A
Explanation: Allopatric populations are populations of the same species that are geographically isolated from one another.


47. Which of the following is an example of adaptive radiation?

  • A) The different beak sizes of Darwin's finches
  • B) The extinction of dinosaurs
  • C) The change in fur color in animals living in cold climates
  • D) The migration of animals to new areas

Answer: A
Explanation: Adaptive radiation refers to the rapid diversification of a species into multiple forms, as seen with Darwin's finches adapting to different niches.


48. Which of the following best describes speciation?

  • A) The process of a single species splitting into two or more distinct species
  • B) The gradual change of organisms over time
  • C) The random changes in allele frequencies
  • D) The migration of organisms from one area to another

Answer: A
Explanation: Speciation is the process by which a single species splits into two or more distinct species due to reproductive isolation.


49. Which of the following is a key principle of Lamarck's theory of evolution?

  • A) Inheritance of acquired characteristics
  • B) Natural selection
  • C) Genetic mutation
  • D) All of the above

Answer: A
Explanation: Lamarck proposed that traits acquired during an organism's lifetime can be passed on to its offspring, a concept known as the inheritance of acquired characteristics.


50. Which of the following is an example of a genetic mutation?

  • A) A change in the allele frequency of a population
  • B) A sudden change in the genetic code of an organism
  • C) The development of antibiotic resistance in bacteria
  • D) Both B and C

Answer: D
Explanation: Both a sudden genetic mutation and the development of antibiotic resistance in bacteria are examples of mutations in genetic material.