Question Bank — Evolution

Section A — MCQs (10 questions, 1 mark each)

1. The Big Bang theory explains the origin of the universe as a singular huge explosion. The first cellular forms of life on Earth appeared approximately:
   (a) 4.5 billion years ago
   (b) 2000 million years ago
   (c) 500 million years ago
   (d) 3 billion years ago

2. Louis Pasteur’s experiment using pre-sterilised flasks demonstrated that:
   (a) Life originates from decaying matter
   (b) Life comes only from pre-existing life
   (c) Spores are transferred between planets
   (d) Chemical evolution precedes biological evolution

3. Which of the following represents an example of homologous organs?
   (a) Wings of butterfly and birds
   (b) Thorn of Bougainvillea and tendril of Cucurbita
   (c) Eye of octopus and mammals
   (d) Flippers of penguins and dolphins

4. The process of evolution of different species in a given geographical area starting from a point and radiating to other habitats is called:
   (a) Convergent evolution
   (b) Adaptive radiation
   (c) Saltation
   (d) Genetic drift

5. According to the Hardy-Weinberg principle, the sum total of all allelic frequencies in a population is:
   (a) 0
   (b) 0.5
   (c) 1
   (d) 2

Assertion-Reason Questions

6. Assertion (A): Industrial melanism in peppered moths is an example of evolution by anthropogenic action.
   Reason (R): In polluted areas, dark-winged moths survived better due to camouflage against sooty tree trunks.
   (a) Both A and R are true and R is the correct explanation of A
   (b) Both A and R are true but R is not the correct explanation of A
   (c) A is true but R is false
   (d) A is false but R is true

7. Assertion (A): Homology indicates common ancestry.
   Reason (R): Homologous structures perform the same function in different organisms.
   (a) Both A and R are true and R is the correct explanation of A
   (b) Both A and R are true but R is not the correct explanation of A
   (c) A is true but R is false
   (d) A is false but R is true

8. The first mammals were small-sized and resembled:
   (a) Dinosaurs
   (b) Shrews
   (c) Coelacanth
   (d) Ichthyosaurs

9. Which of the following is an example of convergent evolution?
   (a) Darwin’s finches
   (b) Australian marsupials and placental mammals
   (c) Thorn of Bougainvillea and tendril of Cucurbita
   (d) Vertebrate hearts

10. The brain capacity of Homo erectus was approximately:
    (a) 650–800 cc
    (b) 900 cc
    (c) 1400 cc
    (d) 500 cc

Section B — Very Short Answer (6 questions, 2 marks each)

1. Differentiate between homologous and analogous organs with one example of each from the chapter.
2. What is the founder effect? How does it relate to genetic drift?
3. State the Oparin-Haldane hypothesis regarding the origin of life.
4. Name the two key concepts of Darwinian theory of evolution.
5. What were the conditions created by S.L. Miller in his experiment?
6. Why is the study of fossils called paleontological evidence for evolution?

Section C — Short Answer (5 questions, 3 marks each)

1. Explain the experiment conducted by Louis Pasteur that dismissed the theory of spontaneous generation.
2. Describe the three connotations of the theory of special creation and how they were challenged in the nineteenth century.
3. What is adaptive radiation? Explain with reference to Darwin’s finches.
4. List the five factors that affect Hardy-Weinberg equilibrium.
5. Briefly describe the sequence of human evolution from Dryopithecus to Homo sapiens as given in the chapter.

Section D — Long Answer (3 questions, 5 marks each)

1. Describe the operation of natural selection on different traits with the help of a labelled diagram showing stabilising, directional and disruptive selection. (Diagram description required)
2. Explain the evidences for evolution from comparative anatomy and morphology. Differentiate between divergent and convergent evolution with suitable examples from the chapter.
3. Give a brief account of the evolution of life forms on Earth from the appearance of the first cellular forms to the dominance of reptiles and mammals. Include the approximate geological time periods mentioned.

Section E — Case/Source-Based (2 questions, 4 marks each)

Case 1

During his voyage on H.M.S. Beagle, Charles Darwin observed small black birds called Darwin’s finches on the Galapagos Islands. He noted that all varieties evolved on the island itself from an original seed-eating stock. Different forms with altered beaks arose, enabling them to become insectivorous and vegetarian finches.

(a) What is the process illustrated by Darwin’s finches?
(b) How does this process differ from convergent evolution?
(c) Name another group of animals that shows a similar phenomenon in Australia.
(d) Why is this considered an example of adaptive radiation?

Case 2

In England, before industrialisation, white-winged moths were more common on trees covered with white lichens. After industrialisation, the proportion reversed and dark-winged (melanised) moths became more common. Lichens are indicators of industrial pollution and do not grow in polluted areas.

(a) What phenomenon is illustrated by the change in moth population?
(b) Explain the role of natural selection in this change.
(c) Why did the count of melanic moths remain low in rural areas?
(d) How does this support the idea that evolution is a stochastic process?