CBSE Class 12 Biology Evolution Worksheet Set B

Evolution MCQ Questions with Answers Class 12 Biology

Question- Find the odd one out w.r.t. evolution
(1) Seal’s flipper
(2) Bat’s wing
(3) Horse’s foot
(4) Butterfly’s wings
Answer (4)

Question- In 1938, a coelacanth was found in
(1) South America
(2) South Africa
(3) Australia
(4) England
Answer (2)

Question- Fossils discovered in Java in 1891 belonged to
(1) Homo habilis
(2) Neanderthal man
(3) Homo erectus
(4) Ramapithecus
Answer (3)

Question-Which of the following is not vestigeal organ in human beings?
(1) Rudimentary ear muscles and third molars (wisdom teeth), body hair
(2) Coccygeal tail vertebrae and scalp muscles
(3) Vermiform appendix and nictitating membrane of the eye
(4) Ear pinna, patella, olecranon process
Answer (4)

Question-Which of the following is a vestigial organ?
(1) Vermiform appendix
(2) Atlas
(3) Premolars
(4) Incisors
Answer (1)

Question- Find the odd one out related to evolution
(1) Vertebrate hearts
(2) Vertebrate brains
(3) Wings of butterfly and of birds
(4) Forelimbs of mammals
Answer (3)

Question-Which of the following is not a vestigial organ?
(1) Scalp hair
(2) Epiglottis
(3) Vermiform appendix
(4) Wisdom tooth
Answer (2)

Question-The origin of seeds in the land plants was achieved about 345 million years ago, in lineages recognised as ancestral to all more advanced vascular plants in
(1) Rhynia
(2) Tracheophyte ancestor
(3) Seed ferns
(4) Conifers
Answer (3)

Question-The rate of appearance of new life forms is linked to their
(1) Acquired traits
(2) Nonheritable characters
(3) Life span
(4) Cranial capacities
Answer (3)

Question-Evolutionary process, giving rise to new species adapted to new habitats and ways of life, is called as adaptive radiation, for example
(1) Darwin’s Finches in Galapagos Islands
(2) Australian marsupials that radiated to form new species
(3) Wolf and Tasmanian Wolf
(4) Both (1) & (2)
Answer (4)

Question-Which of the following is a placental mammal not marsupial?
(1) Wombat
(2) Bobcat
(3) Bandicoot
(4) Tasmanian tiger cat
Answer (2)

Question-When more than one adaptive radiations appeared to have occurred in an isolated geographical area, it is called
(1) Divergent evolution
(2) Convergent evolution
(3) Anthropogenic evolution
(4) Saltation
Answer (2)

Question-Which of the following fact is not true for Homo habilis?
(1) They had a brain capacity of 1400cc
(2) They were the first human-like being
(3) They showed the hominid features
(4) They probably did not eat meat
Answer (1)

Question- Theory of panspermia was proposed to explain the
(1) Origin of universe
(2) Origin of life
(3) Origin of earth
(4) Evolution of life
Answer (2)

Question-As horse evolved, there was progressive reduction in number of toes. Which of the following is correct sequence in the evolution of horse?
(1) Orohippus, Hyracotherium, Mesohippus, Callipus, Merychippus, Pliohippus, Equus
(2) Hyracotherium, Orohippus, Mesohippus, Merychippus, Pliohippus, Equus
(3) Orohippus, Callipus, Hyracotherium, Mesohippus, Merychippus, Pliohippus, Equus
(4) Hyracotherium, Mesohippus, Orohippus, Callipus, Merychippus, Pliohippus and Equus
Answer (2)

Question-According to the discovery made in 1980's. RNA can act like enzyme to assemble new RNA molecules on RNA template. Which of the following statements is not proved by this theory?
(1) Coacervates may not have been the first step in the evolution of life
(2) Perhaps the first macromolecule was RNA
(3) Coacervates were the basis for the first cell
(4) After formation of RNA, stability of molecule improved by surrounding RNA within a coacervate
Answer (3)

Question- The scientist related with the theory of biogenesis and experiments with swan-necked flasks is
(1) Van Helmont
(2) Louis Pasteur
(3) Miller
(4) Haeckel
Answer (2)

Question- An experiment to prove that organic compounds were the basis of life, was performed by
(1) Van Helmont
(2) Oparin
(3) S. Miller
(4) Fox
Answer (3)

Question- Theory of abiogenesis or spontaneous generation was finally disapproved by
(1) Louis Pasteur
(2) A.I. Oparin
(3) A.R. Wallace
(4) Sydney Fox
Answer (1)

Question-Which of the following theory is related to transfer of life from one planet to another?
(1) Theory of special creation
(2) Theory of biogenesis
(3) Theory of spontaneous generation
(4) Cosmozoic theory
Answer (4)

Question-According to cosmozoic theory, life comes on earth from other planets in space in the form of
(1) Spores
(2) Seeds
(3) Gametes
(4) All of these
Answer (4)

Question- H.C. Urey wrote the following book
(1) The Planets
(2) Origin of Life
(3) The Origin of Species
(4) None of these
Answer (1)

Question-Russian scientist who proposed the theory of origin of life was
(1) Oparin
(2) Haldane
(3) Miller
(4) None of these
Answer (1)

Question-Origin of earth dates back to
(1) 10,000–15,000 million years ago
(2) 4000–4600 million years ago
(3) 500–1000 million years ago
(4) 2000–3000 million years ago
Answer (2)

Question-The English scientist who worked on the origin of life and settled in India?
(1) A. I. Oparin
(2) J. B. S. Haldane
(3) Louis Pasteur
(4) Van Helmont
Answer (2)

Question-All of the following conditions were present on early earth, except
(1) High temperature
(2) Volcanic storms
(3) Oxidising atmosphere
(4) Reducing atmosphere
Answer (3)

Question-A.I. Oparin wrote
(1) Origin of Species
(2) Origin of Life
(3) Philosophie Zoologique
(4) The Planet
Answer (2)

Question-The theory that living organisms on the earth came from outer space is based on the study of
(1) Igneous rocks
(2) Sedimentary rocks
(3) Meteorites
(4) Moon soil
Answer (3)

Question-What did S.L. Miller observe in his experimental set-up?
(1) Formation of sugars and nitrogenous bases
(2) Formation of amino acids
(3) Formation of pigments
(4) Formation of fats
Answer (2)

Question-The proponent of the theory of spontaneous generation was
(1) Louis Pasteur
(2) Van Helmont
(3) Spallanzani
(4) Francisco Redi
Answer (2)

Question- S.L.Miller conducted an experiment in 1953 to support the
(1) Theory of spontaneous generation
(2) Biogenesis
(3) Chemical evolution of life
(4) Natural selection
Answer (3)

Question-One of the following appeared on the earth with the coming of the plants and was absent in the past
(1) Carbon dioxide
(2) Methane
(3) Ammonia
(4) Oxygen
Answer (4)

Question-Who finally refuted the theory of spontaneous generation and experimentally disproved it?
(1) Thomas Malthus
(2) Alfred Wallace
(3) Louis Pasteur
(4) Charles Darwin
Answer (3)

Question-Simple one-celled cyanobacteria like organisms appeared on earth
(1) 5600 million years ago
(2) 5000 million years ago
(3) 4600 million years ago
(4) 3.3 to 3.5 billion years ago
Answer (4)

Very Short Answer Questions

Question. Mention one example each from plants and animals exhibiting divergent evolution.
Answer. Thorn of Bougainvillea and tendrils of Cucurbita, forelimbs of whales, bats, cheetah and humans (all mammals)/vertebrate hearts/vertebrates brains. (Any one)

Question. Identify the examples of homologous structures from the following:
(i) Vertebrate hearts
(ii) Thorns in Bougainvillea and tendrils of Cucurbita.
(iii) Food storage organs in sweet potato and potato. 
Answer. (i) Vertebrate hearts
(ii) Thorns in Bougainvillea and tendrils of Cucurbita.

Question. Write the similarity between the wing of a butterfly and the wing of a bat. What do you infer from the above with reference to evolution? 
Answer. Wings of a bird and a bat perform the same function of flying despite their structural dissimilarity.
This infers that they are analogous organs It can be inferred that it is of convergent evolution.

Question. “Sweet potato tubers and potato tubers are the result of convergent evolution.” Justify the statement.
Answer. Sweet potato tuber is a modified root whereas potato tuber is a modified stem. These are anatomically different structures but perform the same function of food storage. Therefore, they are the result of convergent evolution.

Question. Comment on the similarity between the wing of a cockroach and the wing of a bird. What do you infer from the above, with reference to evolution? 
Answer. They are similar in function. Thus we infer that these organs are analogous which has resulted in convergent evolution.

Question. Comment on the similarity between the flippers of dolphins and penguins, with reference to evolution.
Answer. Similarity between the flippers of dolphins and penguins is that they perform similar functions though structurally different. Thus, they are analogous organs. These are the result of convergent evolution.

Question. Why are analogous structures a result of convergent evolution? 
Answer. Analogous structures are not anatomically similar, i.e., they do not have common ancestors and evolve for similar function in the same habitat. Therefore, they are said to be a result of convergent evolution.

Question. Mention the type of evolution that has brought the similarity as seen in potato tuber and sweet potato. 
Answer. Convergent evolution

Question. When we say “survival of the fittest”, does it mean that
(a) those which are fit only survive, or
(b) those that survive are called fit.
Comment. 
Answer. Those individuals which survive and reproduce in their respective environment are called fit.

Question. State a reason for the increased population of dark coloured moths coinciding with the loss of lichens (on tree barks) during industrialisation period in England. 
Answer. Natural selection or survival of fittest as nature selected the moths which could match with black surroundings due to soot deposition.

Short Answer Questions

Question. Describe the experiment that helped Louis Pasteur to dismiss the theory of spontaneous generation of life. 
Answer. Two pre-sterilised flasks with killed yeast were taken. One of the flask was sealed, and the other was open to air. Differential growth of life were observed in the two flasks. Life was found only in the open flask.

Question. Diagrammatically represent the experimental set up that proves Oparin–Haldane hypothesis.
Answer. 

Question. Protein synthesis machinery revolves around RNA but in the course of evolution it was replaced by DNA. Justify. 
Answer. Since RNA was unstable and prone to mutations, DNA evolved from RNA with chemical modifications that makes it more stable.
DNA has double stranded nature and has complementary strands. These further resist changes by evolving a process of repair.

Question. Explain divergent evolution with two examples. 
Answer. Some structures developed along different directions due to adaptations to different needs
performing different functions. This is called divergent evolution. Examples:
(i) Forelimbs of whales, bat, cheetah and humans have similar pattern of bones.
(ii) Thorns of Bougainvillea and tendrils of Cucurbita are modifications of stem.

Question. Select two pairs from the following which exhibit divergent evolution. Give reasons for your answer.
(i) Forelimbs of Cheetah and mammals
(ii) Flippers of dolphins and penguins
(iii) Wings of butterflies and birds
(iv) Forelimbs of whales and mammals 
Answer. (i) and (iv) exhibit divergent evolution.
There pairs have similar anatomical structure or origin but perform different functions.

Question. (a) Select the homologous structures from the combinations given below:
(i) Forelimbs of whales and bats
(ii) Tuber of potato and sweet potato
(iii) Eyes of octopus and mammals
(iv) Thorns of Bougainvillea and tendrils of Cucurbita
(b) State the kind of evolution they represent. 
Answer. (a) (i) Forelimbs of whales and bats.
(iv) Thorns of Bougainvillea and tendrils of Cucurbita.
(b) Divergent evolution.

Question. How do homologous organs represent divergent evolution? Explain with the help of a suitable example.
Answer. Organs with similar structure or same origin developed along different directions due to adaptation or different needs, to perform different functions are called homologous orgAnswer.For example, the fore limbs of some animals (Vertebrates) like whales, bats, cheetah and human have similar anatomical structure (i.e., humerus, radius, ulna, carpals, metacarpals and phalanges) develop differently to meet different need and to perform different functions.

Question. (a) Select the analogous structures from the combinations given below:
(i) Forelimbs of whales and bats
(ii) Eyes of octopus and mammals
(iii) Tuber of sweet potato and potato
(iv) Thorns of Bougainvillea and tendrils of Cucurbita.
(b) State the kind of evolution they represent. 
Answer. (a) (ii) and (iii) are analogous structures.
(b) Convergent evolution.

Question. State Hardy–Weinberg principle of genetic equilibrium. Knowing that genetic drift disturbs this equilibrium, mention what does this disturbance in genetic equilibrium leads to. 
Answer. Hardy–Weinberg principle states that gene pool remains constant, i.e., the allele frequencies in a population are stable and remains constant from generation to generation. Genetic drift refers to change in allele frequencies of a population occurring by chance. The change in allele frequency may be so different that the population becomes a different species. This effect is called founder effect.

Question. (a) Rearrange the following in an ascending order of evolutionary tree: reptiles, salamanders, lobefins, frogs.
(b) Name two reproductive characters that probably make reptiles more successful than amphibians.
Answer. (a) Lobefins, frogs, salamanders, reptiles
(b) Reptiles are more successful than amphibians as:
(i) reptiles lay eggs on land.
(ii) reptiles lay thick shelled eggs which do not dry up in sun unlike those of amphibians.

Long Answer Questions

Question. What are analogous structures? How are they different from homologous structures? Provide one example for each. 
OR
Differentiate between homology and analogy. Give one example of each. 
Answer. Differences between homology and analogy

Question. (a) What is adaptive radiation?
(b) Explain with the help of a suitable example where adaptive radiation has occurred to represent convergent evolution.
OR
What is adaptive radiation? When can adaptive radiation be referred to as convergent evolution? Give an example. 
Answer. (a) The process of evolution of different species in a given geographical area starting from a point and radiating to other areas of geography (habitats) is called adaptive radiation.
(b) When more than one adaptive radiation occurs in an isolated geographical area (representing different habitats), it can be called as convergent evolution.
For example, similarity between some individual members of placental mammals and marsupial mammals argues strongly that they are the result of convergent evolution. These animals have similar forms because of evolution in different, isolated areas because of similar selective pressures in similar environments. This means marsupials in Australia resemble placental mammals in the rest of the world. They evolved in isolation after Australia separated from other continents.

Question. Name and explain the evolutionary concept represented in the illustration given below:

Answer. The illustration represents adaptive radiation.
 

Question. (a) Explain adaptive radiation with the help of a suitable example.
(b) Cite an example where more than one adaptive radiations have occurred in an isolated geographical area. Name the type of evolution your example depicts and state why it is so named.
Answer. (a) Adaptive radiation can be observed in black birds of Galapagos islands, which are also called Darwin’s finches. These birds evolved on the island itself from the original seed eating features. Many forms with offered beaks arose which enabled them to become insectivorous and vegetarian in different habitats of the island.
(b) More than one adaptive radiation have occurred in Australian marsupials and placental mammals.
The example depicts convergent evolution. It is named so, because more than one adaptive radiation occurred in isolated geographical area.

Question. According to Darwinian theory of natural selection the rate of appearance of new forms is linked to the life-cycle or the life-span of an organism. Explain with the help of an example.
Answer. A colony of bacteria (say A) growing in a given medium has built in variation in terms of ability to utilise a feed component, a change in the medium composition would bring out only that part of the population(say B) that can survive under the new conditions.
In due course of time this variant population outgrows the others and appears as new species, thus organisms with shorter life-cycle or life-span will undergo evolution faster. For the same thing to happen in fish or fowl it would take millions of years as life spans of these animals are in years,

Question. How does industrial melanism support Darwin’s theory of Natural Selection? Explain.
Answer. Before industrial evolution the environment was unpolluted. The lichens on the barks of trees were pale. The white-winged moths could easily camouflage, while the dark-winged were spotted out by the birds for food. Hence, they could not survive. After industrial revolution the lichens became dark (due to soot deposit). This favoured the dark-winged moths while the white-winged were picked by birds. The population of the former which was naturally selected increased.

Question. Rearrange Ramapithecus, Australopithecus and Homo habilis in the order of their evolution on the Earth. Comment on their evolutionary characteristics. 
Answer. The order of evolution on the earth is:
Ramapithecus → Australopithecus → Homo habilis
Ramapithecus were hairy and walked–like gorilla and chimpanzees. They were more man like.
Australopithecus hunted with stone weapons and ate fruit.
Homo habilis had a brain capacity 650-800 cc and probably did not eat meat.

Question. Write the characteristics of Ramapithecus, Dryopithecus, and Neanderthal man.
Answer. Ramapithecus: hairy, walked–like gorillas and chimpanzees, more man like.
Dryopithecus: hairy, walked–like gorillas and chimpanzees, more ape-like.
Neanderthal man: brain size is 1400 cc, used hides to protect their body, buried their dead.

Question. (a) Name the ancestors of progymnosperm.
(b) Name the ancestors of herbaceous and arborescent lycopod.
(c) Name the ancestors of cycads.
Answer. (a) Psilophyton
(b) Zosterophyllum
(c) Progymnosperm 

Question. (a) What was proposed by Oparin and Haldane on origin of life? How did S.L. Miller’s experiment support their proposal?
(b) Which human chromosome has (i) maximum number of genes, and which one has
(ii) fewest genes?
(c) Write the scientific importance of single nucleotide polymorphism identified in human genome. 
Answer. (a) Theory of chemical evolution or Oparin–Haldane theory: This theory states that life originated from pre-existing non-living organic molecules (e.g., RNA, protein, etc.). S.L. miller conducted an experiment where he created conditions similar to primitive atmosphere in a flask like high temperature, reducing atmosphere consisting of HCl, NH3, etc. When an electric discharge was created at 800°C, after a week, presence of amino acids and complex molecules like sugars, nitrogen bases, pigments, fats were observed in the flask.
(b) Chromosome 1 has most genes (2968) and the Y chromosome has fewest genes (231).
(c) This information promises to revolutionise the processes of finding chromosomal locations for disease-associated sequences and tracing human history.

Question. (a) Differentiate between analogy and homology giving one example each of plant and animal respectively.
(b) How are they considered as an evidence in support of evolution?
Answer. (a) In some animals, the same structure developed along different directions due to adaptations to different needs. This is divergent evolution and is called homology. Homology indicates common ancestry. For example, vertebrate hearts or brains. In plants also, the thorn and
tendrils of Bougainvillea and Cucurbita represent homology.
(b) Wings of butterfly and of birds look alike. They are not anatomically similar structures though they perform similar functions. Analogy results from convergent evolution in which different structures evolve for the same function and hence have similarity. Sweet potato (root modification) and potato (stem modification) is another example for analogy. 

Question. (a) What are fossils? How are they an evidence for evolution?
(b) “Anthropogenic action can lead to evolution.” Explain with the help of an example.
Answer. (a) Fossils are remains or impression of hard parts of life-forms that existed in past. They are found in rocks.
Study of fossils in different sedimentary layers indicates the geological periods in which they existed and showed that life forms varied over time.
(b) Excess use of herbicides, pesticides, etc., has only resulted in selection of resistant varieties in a much lesser time scale. This is also true for microbes against which we employ antibiotics or drugs against eukaryotic organisms/ cell. Hence, resistant organisms/cells are appearing in a time scale of months or years and not centuries. These are examples of evolution by anthropogenic action.

Question. (i) Natural selection operates when nature selects for fitness. Explain.
(ii) The rate of appearance of new forms is linked to the lifespan of an organism. Explain with the help of a suitable example. 
Answer. (i) Natural resources are limited, populations are stable in size, members of a population vary in characteristics even though they look superficially similar. Theoretically, population will increase exponentially but the population sizes in reality are limited thus leading to competition. Only the ones which are fit and adapt themselves are able to survive. They grow at the cost of others and flourish. This was called as natural selection by Darwin.
(ii) According to Darwin, the fitness of an organism is measured by its reproductive ability. Also the appearance of new forms is linked to the lifespan of an organism. The greater its lifespan, the more it can reproduce and hence, greater new forms would appear. This can be observed in the development of dark-winged moths due to industrial melanism. For details, refer to the above qustion.

Question. (a) How did Darwin explain adaptive radiation? Give another example exhibiting adaptive radiation.
(b) Name the scientist who influenced Darwin and how?
Answer. (a) During his journey Darwin went to Galapagos Islands. There he observed an amazing diversity of creatures. Of particular interest were small black birds, later called Darwin’s Finches which amazed him. He realised that there were many varieties of finches in the same island. All the varieties, he conjectured, evolved on the island itself. From the original seed-eating features, many other forms with altered beaks arose, enabling them to become insectivorous and vegetarian finches. This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation. Darwin’s finches represent one of the best examples of this phenomenon. Another example is Australian marsupials.
(b) Thomas Malthus influenced Darwin.
According to Malthus, population size grows exponentially (due to maximum reproduction).
However, the population size remains limited due to limited natural resources which leads to competition. 

Question. (a) Explain Darwinian theory of evolution with the help of one suitable example. State the two key concepts of the theory.
(b) Mention any three characteristics of Neanderthal man that lived in near east and central Asia.
Answer. (a) According to Darwin, evolution took place by selection. The rate of appearance of new forms is linked to the life cycle at the life span. Some organisms are better adapted to survive in an otherwise hostile environment (Survival of the fittest). For example, antibiotic resistance in bacteria. When a bacterial population was grown on an agar plate containing antibiotic penicillin, the colonies sensitive to penicillin died, whereas the ones resistant to penicillin survived due to adaptation.
Key concepts of the theory are
(i) Branching descent
(ii) Natural selection
(b) Characteristics of Neanderthal man:
(i) Their brain size was 1400 cc.
(ii) They used hides to protect their bodies.
(iii) They buried their dead.

More Question

1 State the theory of spontaneous generation.

2 What is founder effect?

3 Who among the Dryopithecus and Ramapithecus was more man-like?

4 What causes speciation according to Hugo de Vries?

5 Name any two vertebrate body parts that are homologous to human forelimbs?

6 What are the key concepts in the evolution theory of Darwin?

7 Why are the wings of butterfly and of a bat called analogous?

8 How is Darwin’s concept of evolution different from de Vries?

a) Mention the specific geographical region where these organisms are found.

b) Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region.

c) Explain giving reasons the existence of placental wolf and Tasmanian wolf sharing the same habitat.