Evolution: Class 12 Important Questions with Answers

Practice set: test yourself

Try every question before looking at the answers below. 64 or more out of 80 means you are ready for the board.

C. Very short answer (1 mark each)

1. Name the gases in Miller's flask.
2. Give one example of analogous organs.
3. What is a founder effect?
4. Name the plant de Vries worked on.
5. Which primate lived about 15 mya?
6. What is the age of the earth?
7. Name a living fossil fish found in 1938.
8. Give the placental counterpart of the numbat.
9. What does $2pq$ represent?
10. Name the theory that life came from outer space.

D. Short answer I (2 marks each)

1. Distinguish divergent and convergent evolution.
2. What did Miller's experiment show?
3. Explain industrial melanism.
4. State two postulates of Darwin's theory.
5. What is adaptive radiation? Give an example.
6. List the five factors affecting Hardy–Weinberg equilibrium.
7. How does anthropogenic action affect evolution?
8. Give two features of Neanderthal man.

Rough work

E. Short answer II (3 marks each)

1. Derive the Hardy–Weinberg expression.
2. In a population 9% are recessive (aa). Find the percentages of AA and Aa.
3. Explain three types of natural selection with graphs.
4. Compare Lamarck's and Darwin's ideas with the giraffe example.
5. Describe Pasteur's experiment.
6. Give three evidences of evolution.

F. Long answer (5 marks each)

1. Describe the Oparin–Haldane theory and Miller's experiment with a diagram.
2. Trace human evolution from Dryopithecus to Homo sapiens.

G. HOTS (higher-order thinking)

1. Why did dark moths decrease again after pollution control?
2. Why is reproductive fitness more important than survival?
3. Why are Australian marsupials so diverse?
4. Why is genetic drift stronger in small populations?

20 MCQs

1. The earth is about
   (a) 20 billion years old (b) 4 million years (c) 4.5 billion years old (d) 1 billion years
2. Miller obtained
   (a) amino acids (b) DNA (c) proteins (d) cells
3. Life from pre-existing life was shown by
   (a) Oparin (b) Haldane (c) Miller (d) Pasteur
4. Homologous organs
   (a) wings of insect and bird (b) forelimbs of whale and bat (c) eyes of octopus and man (d) flippers of penguin and dolphin
5. Analogous organs show
   (a) divergent (b) convergent evolution (c) common ancestry (d) mutation
6. Darwin's finches show
   (a) convergent evolution (b) genetic drift (c) saltation (d) adaptive radiation
7. After industrialisation in England
   (a) dark moths increased (b) white moths increased (c) both decreased (d) lichens increased
8. Natural selection favouring both extremes
   (a) stabilising (b) directional (c) disruptive (d) neutral
9. Use and disuse was proposed by
   (a) Darwin (b) Wallace (c) de Vries (d) Lamarck
10. Saltation means
    (a) small changes (b) single-step large mutation (c) drift (d) migration
11. If $q^2=0.25$, $p$ =
    (a) 0.25 (b) 0.75 (c) 0.5 (d) 0.05
12. Which does not disturb H–W equilibrium?
    (a) random mating in a large population (b) mutation (c) gene flow (d) selection
13. The first human-like being
    (a) Homo erectus (b) Homo habilis (c) Dryopithecus (d) Neanderthal
14. Brain 1400 cc
    (a) Homo habilis (b) Homo erectus (c) Neanderthal (d) Australopithecus
15. Agriculture began about
    (a) 1 lakh years ago (b) 500 years ago (c) 1 million years ago (d) 10,000 years ago
16. Marsupial counterpart of the flying squirrel
    (a) flying phalanger (b) numbat (c) cuscus (d) wombat
17. Lobefins evolved into
    (a) amphibians (b) reptiles (c) birds (d) mammals
18. Dinosaurs disappeared about
    (a) 200 mya (b) 2 mya (c) 15 mya (d) 65 mya
19. Founder effect is a type of
    (a) mutation (b) genetic drift (c) selection (d) migration
20. Antibiotic resistance spreads because of
    (a) use and disuse (b) Lamarckism (c) selection of resistant variants (d) saltation

1 (c) · 2 (a) · 3 (d) · 4 (b) · 5 (b) · 6 (d) · 7 (a) · 8 (c) · 9 (d) · 10 (b) · 11 (c) · 12 (a) · 13 (b) · 14 (c) · 15 (d) · 16 (a) · 17 (a) · 18 (d) · 19 (b) · 20 (c)

Assertion–Reason (6)

(a) Both true, R explains A. (b) Both true, R does not explain A. (c) A true, R false. (d) A false, R true.

1. A: Forelimbs of man and whale are homologous. R: They have the same basic structure but different functions.
2. A: Dark moths increased in industrial England. R: Soot-covered trunks camouflaged them from predators.
3. A: Miller's experiment supported chemical evolution. R: He formed amino acids from inorganic gases.
4. A: Wings of butterfly and bird are homologous. R: They perform the same function.
5. A: Human evolution is adaptive radiation. R: Only Homo sapiens survives today.
6. A: Genetic drift can change allele frequencies. R: It acts by chance, especially in small populations.

Key: 1 (a) · 2 (a) · 3 (a) · 4 (d) · 5 (d) · 6 (a)

Answers to the practice set