Evolution — Class 12 MCQs with Answers

Evolution — important questions & MCQs with answers (Class 12 Biology)

14 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 76 are timed and scored when you sign in.

1. Q1Easy

   Theory of natural selection by:

   A.Mendel

   B.Lamarck

   C.Charles Darwin✓ Correct

   D.Pasteur

   Answer: C. Charles Darwin

   Explanation: Charles Darwin proposed natural selection in On the Origin of Species (1859): heritable variation plus differential survival and reproduction drives evolutionary change, distinct from Lamarck's use-and-disuse idea.

2. Q2Easy

   Direct evidence of evolution:

   A.Memes

   B.Comments

   C.Random data

   D.Fossils✓ Correct

   Answer: D. Fossils

   Explanation: Fossils are time-stamped remains preserved in rock strata, giving direct palaeontological evidence of extinct organisms and evolutionary change, unlike embryological or molecular evidence which is only indirect.

3. Q3Easy

   The theory of natural selection was proposed by:

   A.Charles Darwin✓ Correct

   B.Lamarck

   C.Mendel

   D.Oparin

   Answer: A. Charles Darwin

   Explanation: Darwin, and independently Alfred Wallace, proposed natural selection: organisms with favourable heritable variations survive and reproduce more, gradually reshaping populations — distinct from Lamarck's acquired-character idea.

4. Q4Easy

   The chemical/abiogenic origin of life was proposed by:

   A.Pasteur

   B.Darwin and Wallace

   C.Watson and Crick

   D.Oparin and Haldane✓ Correct

   Answer: D. Oparin and Haldane

   Explanation: Oparin and Haldane independently proposed chemical (abiogenic) evolution: under Earth's early reducing atmosphere, simple gases combined into organic monomers, the first step toward life — distinct from Pasteur's biogenesis.

5. Q5Easy

   The idea of 'inheritance of acquired characters' was given by:

   A.de Vries

   B.Darwin

   C.Lamarck✓ Correct

   D.Hardy

   Answer: C. Lamarck

   Explanation: Lamarck proposed inheritance of acquired characters — traits gained through use during an organism's lifetime pass to offspring. Darwin rejected this; only heritable genetic variation, not use-and-disuse, is selected.

6. Q6Easy

   The Miller–Urey experiment demonstrated the formation of:

   A.Complete cells

   B.Amino acids from simple gases✓ Correct

   C.DNA from RNA

   D.Fossils

   Answer: B. Amino acids from simple gases

   Explanation: Miller and Urey sparked a mix of methane, ammonia, hydrogen and water vapour simulating early Earth's reducing atmosphere and obtained amino acids, showing organic monomers can form abiotically, not complete cells.

7. Q7Medium

   Lamarck's theory: inheritance of:

   A.Acquired characters (now disproved)✓ Correct

   B.Genetic mutations only

   C.Random selection

   D.None

   Answer: A. Acquired characters (now disproved)

   Explanation: Lamarck's use-and-disuse hypothesis claimed traits gained during an organism's life, like a stretched neck, pass to offspring; this inheritance of acquired characters is now disproved, unlike Darwin's natural selection.

8. Q8Medium

   Homologous organs (e.g., human arm, whale flipper, bat wing):

   A.Random similarity

   B.Same function only

   C.Indicate common ancestry✓ Correct

   D.No relation

   Answer: C. Indicate common ancestry

   Explanation: Homologous organs like the human arm, whale flipper and bat wing share the same bony plan and embryonic origin from a common ancestor, then diverged in function — divergent evolution, not the convergence behind analogous organs.

9. Q9Medium

   The Hardy–Weinberg equation is:

   A.p² + 2pq + q² = 1✓ Correct

   B.p + q = 2

   C.p² − q² = 1

   D.p² + q² = 1

   Answer: A. p² + 2pq + q² = 1

   Explanation: The Hardy-Weinberg equation p squared + 2pq + q squared = 1 partitions a population into homozygous dominant (p squared), heterozygous (2pq) and homozygous recessive (q squared) genotype frequencies summing to the whole.

10. Q10Medium

    In the Miller–Urey apparatus, the gases used to simulate the primitive atmosphere were:

    A.O₂, CO₂ and N₂

    B.CH₄, NH₃, H₂ and water vapour✓ Correct

    C.Only O₂

    D.Cl₂ and H₂S

    Answer: B. CH₄, NH₃, H₂ and water vapour

    Explanation: Miller and Urey's apparatus simulated the primitive, oxygen-free reducing atmosphere using methane, ammonia, hydrogen and water vapour, sparked with electric discharge to mimic lightning, and produced amino acids.

11. Q11Medium

    Which factor does NOT disturb Hardy–Weinberg equilibrium?

    A.Mutation

    B.Random mating in a large population✓ Correct

    C.Genetic drift

    D.Natural selection

    Answer: B. Random mating in a large population

    Explanation: Random mating within a large population is the condition Hardy-Weinberg equilibrium requires, not a force that disturbs it; mutation, migration, genetic drift and natural selection are the five factors that shift allele frequencies.

12. Q12Hard

    Hardy-Weinberg principle holds when:

    A.Inbreeding

    B.Strong selection

    C.Bottleneck

    D.No mutation, migration, selection, drift; random mating✓ Correct

    Answer: D. No mutation, migration, selection, drift; random mating

    Explanation: Hardy-Weinberg equilibrium needs a large population with random mating and no mutation, migration, natural selection or genetic drift; any one of these five forces shifts allele frequencies away from p squared + 2pq + q squared = 1.

13. Q13Hard

    Wings of bird and butterfly are:

    A.Analogous (convergent evolution)✓ Correct

    B.Homologous

    C.Identical

    D.Vestigial

    Answer: A. Analogous (convergent evolution)

    Explanation: Bird and butterfly wings serve the same flight function but evolved independently from unrelated ancestral structures — convergent evolution producing analogous organs, unlike the shared-ancestry homology of vertebrate forelimbs.

14. Q14Hard

    In a population at Hardy–Weinberg equilibrium, the frequency of the recessive allele (q) is 0.2. The frequency of heterozygotes (2pq) is:

    A.0.64

    B.0.04

    C.0.32✓ Correct

    D.0.16

    Answer: C. 0.32

    Explanation: With recessive allele frequency q = 0.2, the dominant allele frequency p = 1 minus q = 0.8, so heterozygote frequency 2pq = 2 times 0.8 times 0.2 = 0.32 — compute p from q first, don't confuse 2pq with q squared alone.

Evolution — FAQs

More Class 12 Biology chapters

• 01Sexual Reproduction in Flowering Plants
• 02Human Reproduction
• 03Reproductive Health
• 04Principles of Inheritance and Variation
• 05Molecular Basis of Inheritance
• 07Human Health and Disease

Class 12 — other subjects

• Class 12 Chemistry chapters
• Class 12 Computer Science chapters
• Class 12 English chapters
• Class 12 Mathematics chapters
• Class 12 Physics chapters