Chapter Exam

Chapter 6: Evolution — Online MCQ Test

Q: Who proposed that life originated from pre-existing non-living organic molecules through chemical evolution?

Answer: A. Oparin and Haldane — Oparin and Haldane suggested that the first life forms arose from pre-existing organic molecules under primitive Earth conditions.

Q: The primitive atmosphere of Earth was mainly:

Answer: B. Reducing and without free oxygen — According to NCERT, early Earth had a reducing atmosphere containing gases like methane, ammonia, hydrogen and water vapour, with no free oxygen.

Q: In Miller's experiment, the gases used to simulate the primitive atmosphere were:

Answer: B. Methane, ammonia, hydrogen and water vapour — Miller used methane, ammonia, hydrogen and water vapour, and passed electric sparks through them to simulate lightning.

Q: Darwin's book 'On the Origin of Species' was published in:

Answer: C. 1859 — Charles Darwin published 'On the Origin of Species' in 1859, explaining evolution by natural selection.

Q: Which of the following pairs represents homologous organs?

Answer: C. Forelimbs of whale and forelimbs of horse — Forelimbs of whale and horse have the same basic structural plan and origin, though they perform different functions.

Q: Two unrelated species living in similar habitats develop similar body forms. This is most likely due to:

Answer: B. Convergent evolution — Convergent evolution occurs when unrelated organisms independently evolve similar traits due to similar environmental pressures.

Q: A population has 16% individuals with a recessive phenotype. Assuming Hardy-Weinberg equilibrium, what is the frequency of the recessive allele?

Answer: B. 0.40 — The recessive phenotype frequency is q^2 = 0.16, so q = 0.4.

Q: In a population in Hardy-Weinberg equilibrium, 9% of individuals show a recessive trait. What percentage of the population is expected to be heterozygous carriers?

Answer: C. 42% — Here q^2 = 0.09, so q = 0.3 and p = 0.7. Carrier frequency = 2pq = 2 × 0.7 × 0.3 = 0.42 or 42%.

Q: In a Hardy-Weinberg population, 64% individuals show the dominant phenotype for a trait controlled by two alleles. What percentage of dominant-phenotype individuals are heterozygous?

Answer: C. 75% — If dominant phenotype is 64%, recessive phenotype q^2 = 36%, so q = 0.6 and p = 0.4. Heterozygotes are 2pq = 48%, so among 64% dominant individuals, 48/64 = 75%.

BIOLOGY · Grade 12 · CBSE(NCERT)

Practice Chapter 6: Evolution with a free chapter-wise online MCQ test for CBSE(NCERT) Grade 12 BIOLOGY. This chapter covers: Origin of Life Chemical Evolution Natural Selection Darwin Theory Hardy Weinberg Principle Speciation Adaptation Fossils Evolutionary Evidence Genetic Variation. AI-generated questions from basic to board-exam level, with instant results and explanations.

Questions

20m

Time Limit

Attempts Left

10 random questions from this chapter (mixed difficulty)
Questions you've seen before won't repeat until the pool resets
You have 20 minutes — exam auto-submits when time is up
Maximum 3 attempts per chapter
Results and explanations shown immediately after submission

New here? Register free — includes 3 free chapter exams.

Chapter 6: Evolution — Important Questions & Answers (FAQ)

Frequently asked questions from CBSE(NCERT) Grade 12 BIOLOGY — Chapter 6: Evolution, with answers and explanations. These are sample questions; the exam has its own separate question set.

Who proposed that life originated from pre-existing non-living organic molecules through chemical evolution?

A. Oparin and Haldane ✓
B. Darwin and Wallace
C. Mendel and Morgan
D. Watson and Crick

Answer: A. Oparin and Haldane
Oparin and Haldane suggested that the first life forms arose from pre-existing organic molecules under primitive Earth conditions.

The primitive atmosphere of Earth was mainly:

A. Oxidising and rich in oxygen
B. Reducing and without free oxygen ✓
C. Rich in ozone and nitrogen dioxide
D. Similar to the present atmosphere

Answer: B. Reducing and without free oxygen
According to NCERT, early Earth had a reducing atmosphere containing gases like methane, ammonia, hydrogen and water vapour, with no free oxygen.

In Miller's experiment, the gases used to simulate the primitive atmosphere were:

A. Oxygen, nitrogen, carbon dioxide and water vapour
B. Methane, ammonia, hydrogen and water vapour ✓
C. Carbon monoxide, oxygen, nitrogen and hydrogen
D. Sulphur dioxide, nitrogen, oxygen and methane

Answer: B. Methane, ammonia, hydrogen and water vapour
Miller used methane, ammonia, hydrogen and water vapour, and passed electric sparks through them to simulate lightning.

Darwin's book 'On the Origin of Species' was published in:

A. 1809
B. 1831
C. 1859 ✓
D. 1900

Answer: C. 1859
Charles Darwin published 'On the Origin of Species' in 1859, explaining evolution by natural selection.

Which observation best supports chemical evolution as the origin of life?

A. Spontaneous generation of flies from meat
B. Synthesis of amino acids under simulated primitive Earth conditions ✓
C. Production of oxygen by modern plants
D. Inheritance of acquired characters in giraffes

Answer: B. Synthesis of amino acids under simulated primitive Earth conditions
Miller's experiment showed that organic molecules like amino acids could form under primitive Earth-like conditions.

Which of the following pairs represents homologous organs?

A. Wings of butterfly and wings of bird
B. Flippers of penguin and fins of fish
C. Forelimbs of whale and forelimbs of horse ✓
D. Eyes of octopus and eyes of mammals

Answer: C. Forelimbs of whale and forelimbs of horse
Forelimbs of whale and horse have the same basic structural plan and origin, though they perform different functions.

Two unrelated species living in similar habitats develop similar body forms. This is most likely due to:

A. Divergent evolution
B. Convergent evolution ✓
C. Genetic drift only
D. Founder effect

Answer: B. Convergent evolution
Convergent evolution occurs when unrelated organisms independently evolve similar traits due to similar environmental pressures.

A population has 16% individuals with a recessive phenotype. Assuming Hardy-Weinberg equilibrium, what is the frequency of the recessive allele?

A. 0.16
B. 0.40 ✓
C. 0.60
D. 0.84

Answer: B. 0.40
The recessive phenotype frequency is q^2 = 0.16, so q = 0.4.

In a population in Hardy-Weinberg equilibrium, 9% of individuals show a recessive trait. What percentage of the population is expected to be heterozygous carriers?

A. 18%
B. 21%
C. 42% ✓
D. 49%

Answer: C. 42%
Here q^2 = 0.09, so q = 0.3 and p = 0.7. Carrier frequency = 2pq = 2 × 0.7 × 0.3 = 0.42 or 42%.

In a Hardy-Weinberg population, 64% individuals show the dominant phenotype for a trait controlled by two alleles. What percentage of dominant-phenotype individuals are heterozygous?

A. 25%
B. 50%
C. 75% ✓
D. 100%

Answer: C. 75%
If dominant phenotype is 64%, recessive phenotype q^2 = 36%, so q = 0.6 and p = 0.4. Heterozygotes are 2pq = 48%, so among 64% dominant individuals, 48/64 = 75%.

← Previous Chapter

Chapter 5: Molecular Basis of Inheritance

Next Chapter →

Chapter 7: Human Health and Diseases