Biology. TOPIC : Evolution. Marks : 120 mks Time : ½ hr

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1 TOPIC : Evolution Date : Marks : 120 mks Time : ½ hr 1. Consider following statement regarding microspheres. (i) They were spherical in shape and 1 2 m in diameter (ii) They had concentric double-layered boundaries. (iii) They provided partial isolation to contents inside it, from external environment (iv) They had catalytic activity Which of the above statement are incorrect? (a) (i) only (b) (ii) only (c) (iv) only (d) none of the above 2. The prebiotic atmosphere of the earth was of reducing nature. It was transformed into an oxidizing atmosphere of present day due to the emergence of (a) cyanobacteria (b) angiosperms (c) photosynthetic (d) eukaryotic algae 3. In the experiment in given diagram which of the following groups of gases were used to simulate primitive atmosphere? (a) N2, H2, CH4, C2H6 (b) NH3, H2O, CH4, H2 (c) N2O, H2O, NO2, SO2 (d) CH4, H2, NO2, SO2 4. Coacervates are (a) colloid droplets (b) nucleoprotein containing entities (c) both (a) and (b) (d) protobiont 5. The following are some major events in the early history of life: P. First heterotrophic prokaryotes Q. First genes R. First eukaryotes S. First autotrophic prokaryotes T. First animals Which option below places these events in the correct order? (a) PQRST (b) QSPTR (c) QPSRT (d) QSPRT 6. On the primitive earth, polymers such as proteins and nucleic acids in aqueous suspension formed the spherical aggregates. These are called (a) primitosomes (b) liposomes (c) primitogens (d) coacervates 7. Which one of the following options gives one correct example each of convergent evolution and divergent evolution? Convergent evolution Divergent evolution (a) Eyes of octopus and mammals Bones of forelimbs of vertebrates (b) Thorns of Bougainvillea and Wings of butterflies and birds tendrils of Cucurbita (c) Bones of forelimbs of vertebrates Wings of butterfly and birds (d) Thorns of Bougainvillea and tendrils Eyes of octopus and mammals of Cucurbita 8. Which of the following isotopes is used for finding the fossil age more than 4500 years? (a) 238 U (b) 14 C (c) 3 H (d) 206 pb 9. Which is not a vestigial organ in man? (a) Nictitaitng membrane (b) Tail vertebrae (c) Vermiform appendix (d) Nails Page 1 of 6

2 10. Given below are four statements (A-D) each with one or two blanks. Select the option which correctly fills up the blanks in two statements. (A) Wings of butterfly and birds look alike and are the results of (i) evolution. (B) Miller showed that CH4, H2, NH3 and (i) when exposed to electric discharge in a flask resulted in formation of (ii). (C) Vermiform appendix is a (i) organ and an (ii) evidence of evolution. (D) According to Darwin evolution took place due to (i) and (ii) of the fittest. (a) (A)-(i) convergent; (D)-(i) small variations, (ii) survival (b) (A)-(i) convergent; (B)-(i) oxygen, (ii) nucleosides (c) (B)-(i) water vapour, (ii) amino acids; (C)-(i) homologous, (ii) anatomical (d) (C)-(i) vestigial, (ii) anatiomical; (D)-(i) mutations, (ii) multiplication. 11. Read the following statements carefully and select the correct ones. (i) Alfred Wallance, A naturalist who worked in Malay Archipelago had also come to similar conclusions as Darwin around the same time. (ii) August Weismann by careful experimentation demonstrated that life comes only from pre-existing life (iii) The organs which have the same fundamental structure but the different functions are called homologous organs (iv) Sweet potato and potato are examples of homology (a) (i) and (iii) (b) (i) and (ii) (c) (ii) and (iv) (d) (iii) and (iv) 12. Which of the following are necessary for evolution by natural selection to take place? (i) Offspring resemble their parents more than other individuals in the population (ii) Differences among individuals exist and lead to different numbers of successful offsprings being produced (iii) Individuals adjust their development depending on the environment (iv) Every individual possess enormous fertility (v) Populations tend to grow faster than their food supplies (a) (i) and (ii) (b) (ii) and (iv) (c) (i), (iii) and (iv) (c) (iii) and (v) 13. Select the pair which does not match. (a) Coacervates Aggregates of organic compounds separated by an organic membrane (b) Species are not immutable Lamarck (c) Allopatric Separated by space (d) Drawin s finches Unique to Galapagos 14. Replacement of the lighter-coloured variety of peppered moth (Biston betularia) to its darker variety (Biston carbonaria) in England is the example of (a) natural selection (b) regeneration (c) genetic isolation (d) temporal isolation 15. Math column-i with Column-II and select the correct option from the codes given below. Column I Column II A. Saltation (i) Darwin B. Formation of life was preceded by chemical evolution (ii) Louis Pasteur C. Reproductive fitness (iii) de Vries D. Life comes from pre-existing life (iv) Oparin and Haldane (a) A-(iii), B-(iv), C-(i), D-(ii) (b) A-(iv), B-(iii), C-(ii), D-(i) (c) A-(ii), B-(iii), C-(i), D-(iv) (d) A-(i), B-(iv), C-(iii), D-(ii) 16. Math column-i with Column-II and select the correct option from the codes given below. Column I Column II A. Mutation (i) Changes in population s allele frequencies due to chance alone B. Gene flow (ii) Differences in survival and reproduction among variant individuals C. Natural selection (iii) Immigration, emigration change allele frequencies D. Genetic drift (iv) Source of new alleles (a) A-(i), B-(ii), C-(iii), D-(iv) (b) A-(iv), B-(ii), C-(iii), D-(i) (c) A-(v), B-(i), C-(iv), D-(ii) (d) A-(iv), B-(iii), C-(ii), D-(i) Page 2 of 6

3 17. At a particular locus, frequency of allele A is 0.6 and that of allele a is 0.4. What would be the frequency of heterozygotes in a random mating population at equilibrium? (a) 0.36 (b) 0.16 (c) 0.24 (d) Math column-i with Column-II and select the correct option from the codes given below. Column I Column II A. Wallace (i) Essay on population B. Malthus (ii) Biston C. Hardy-Weinberg law (iii) p 2 + q 2 + 2pq = 1 D. Industrial melanism (iv) Co-proposer of natural selection (a) A-(iii), B-(iv), C-(ii), D-(i) (b) A-(ii), B-(i), C-(iv), D-(iii) (c) A-(iv), B-(i), C-(ii), D-(iii) (d) A-(iv), B-(i), C-(iii), D-(ii) 19. Ancient mammals enjoyed a release from competition when the dinosaurs became extinct. Should human work to ensure that such releases from competition continue to occur for us or for other species? (a) No. because it is impossible to predict which species will become dominant if other species become extinct. (b) No, because the species that become dominant will cause the extinction of humans (c) Yes, because the organisms that are released from competition will always form more new species than the number that went extinct (d) Yes, Because new species that evolve are always better organisms than those that went extinct 20. Hardy-Weinberg equilibrium is known to be affected by gene flow, genetic drift, mutation, mutation, genetic recombination and (a) evolution (b) limiting factors (c) saltation (d) natural selection 21. What is the correct arrangement of periods of palaeozoic era in ascending order in geological time scale? (a) Cambrian Devonian Ordovician Silurian Carboniferous Permian (b) Cambrian Ordovician Silurian Devonian Carboniferous Permian (c) Cambrian Ordovician Devonian Silurian Carboniferous Permian (d) Silurian Devonian Cambrian Ordovician Permian Carboniferous 22. Which is the correct order of increasing geological time scale for a hypothetical vertebrate evolution? (a) Cenozoic, Mesozoic, Palaeozoic, Precambrian (b) Cenozoic, Palaeozoic, Mesozoic, Precambrian (c) Precambrian, Cenozoic, Palaeozoic, Mesozoic (d) Precambrian, Palaeozoic, Mesozoic, Cenozoic 23. The devonian period is considered to be as (a) age of fishes (b) age of amphibians (c) age of reptiles (d) age of mammals 24. Which of following represents correct order of evolution? (a) Amoeba Leucosolenia Hydra Ascaris (b) Leucosolenia Hydra Amoeba Ascaris (c) Ascaris Amoeba Leucosolenia Hydra (d) None of these 25. Refer the given statement and select the correct ones. (i) Fossils are remains of hard parts of life forms in rocks (ii) A study of fossils in different sedimentary layers indicates the geological period in which they live. (iii) Radio isotopes are often used to determine the age of the fossils. (iv) Study of fossils is called palaentology (a) (i), (ii), (iii) and (iv) (b) (ii) and (iv) (c) (i), (iii) and (iv) (d) None of these 26. The Jurassic period belongs to the era. (a) Cenozoic (b) Mesozoic (c) Paleozoic (d) proterozoic 3 P a g e

4 27. Amphibians were dominant during period. (a) carboniferous (b) Silurian (c) Ordovician (d) Cambrian 28. The extinct human ancestor, who ate only fruits and hunted with stone weapons was (a) Ramapithecus (b) Australopithecus (c) Dryopithecus (d) Homo erectus 29. Complete the following paragraph by selecting the correct sequence of words from the options given below. The Neanderthal man with a brain size of (i) lived near east and central (ii) between (iii) years back. They used (iv) to protect their body and buried their dead. (i) (ii) (iii) (iv) (a) 500 cc Australia 2,00,000-1,40,000 clothes (b) 900 cc Africa 40,000-8,000 twings (c) 1400 cc Asia 1,00,000-40,000 hides (d) 650 cc Africa 75,000-10,000 leaves 30. Which of the following eras, in geological time scale, corresponds to the period when life had not originated upon the earth? (a) Azoic (b) Palaeozoic (c) Mesozoic (d) Archaeozoic Page 4 of 6

5 Solutions 1. (d) 2. (a) The prebiotic atmosphere of the earth was of a reducing nature i.e. no free oxxugen was available. It was transformed into an oxidizing atmosphere due to the emergence of cyanobacteria. Cyanobacteria apperared about billion years ago. They used water to get hydrogen and released oxygen into the atmosphere. 3. (b) Stanley Miller in 1953 took an air tight apparatus and circulated four gases CH4, NH3, H2 and water vapour through it under electrical discharges from electrodes at 800 C. Then he passed the mixture through a condenser. He performed this experiment continuously in this way for 10 days and analyzed the composition of the liquid inside the apparatus. He found a large number of simple organic compounds including some amino acids such as alanine, glycine and aspartic acid. Miller, thus, proved that organic compounds were basis of life. 4. (c) 5. (c) 6. (d) 7. (a) Development of similar adaptive functional structures in unrelated groups of organisms is called convergent evolution. It shows analogy. Examples are wings of butterfly and birds, eye of the octopus and the mammals, flipper of penguins & dolphins, etc. On the other hand divergent evolution involves the modification of organs to perform different functions as an adaptationto different environments. For example forelimbs of vertebrates (whales, bat, cheetah, human). Though these perform different functions, they have similar anatomical structure. 8. (a) 9. (d) Vestigial organs are those organs which are present in reduced form and do not perform any function in the body but correspond to the fully developed factional organs of related animals. These organs are believed to be remnants of organs which were complete and functional in their ancestors. In man, nails are not vestigial organs. Human body has been described to possess about 90 vestigial organs such as nictitating membrane, vermiform appendix, caudal vertebrae (coccyx or tail bone), third molars etc. vestigial organs in animals include wings of flightless birds such as kiwi, ostrich etc. and pelvic girdles of pythons etc. 10. (a) 11. (a) Louis Pasteur by careful experimentation demonstrated that life comes only from pre-existing life. Sweet potato is an example for analogy. 12. (b) 13. (a) According to Oparin s hypothesis, early protocell could have been a coacervate. Coacervates were non-living structures that led to the formation of the first living cells from which the more complex cells have evolved today. Protocell consisted of carbohydrates, proteins, lipids and nucleic acids that accumulated to form a coacervate. Such a structure could have consisted of a collection of organic macromolecules surrounded by a film of water molecules. This arrangement of water molecules, although not a membrane, could have functioned as a physical barrier between the organic molecules and their surroundings. 14. (a) In England, before industrialization in 1860, it was observed that were more white-winged moths (Biston betularia) on tree trunks than dark-winged or melanised moths (Biston carbonaria). But after industrialization in 1920, there were more dark- winged moths in the same area. Before industrialization, the tree trunks were covered by white-coloured lichens. In that background, the white-winged moths survived but the dark-winged moths were eaten by predators. During post industrialization period, the tree trunks became dark due to industrial smoke and soot. Therefore, the white winged moths did not survive due to predators and darkwinged moths survived i.e., the moths that were hidden in background survived. Thus, industrial melansim supports evolution by natural selection. 15. (a) 16. (d) 17. (d) In a stable population, for a gene with two alleles A (dominant) and a (recessive), if the frequency of A is p and the frequency of a is q, then the frequency of the three possible genotypes (AA,Aa and aa) can be expressed by the Hardy-Weinberg equation: p 2 + 2pq + q 2 = 1 where p 2 = Frequency of AA (homozygous dominant) individuals q 2 = Frequency of aa (homozygous recessive) individuals 2pq = Frequency of Aa (heterozygous) individuals. so, p = 0.6 and q = 0.4 (given) 2pq (frequency of heterozygote) = = (d) 19. (a) 20. (d) Hardy-Weinberg principle describes a theoretical situation in which a population is undergoing no evolutionary change. It states that allele frequencies in a population are stable and constant from generation to generation. There are give factors that affect Hardy-Weinberg Principle. These are mutation, gene flow, genetic drift, genetic recombination and natural selection pressure. 5 P a g e

6 21. (b) Palaeozoic era is the era of ancient life. The correct arrangement of periods of this era is Cambrian Ordovician (age of of invertebrates) Silurian Devonian ( age of fishes) Carboniferous (age of Amphibians) Permian 22. (d) (d) 23. (a) Devonian period occurred about 400 million years ago in palaeozoic era. This period was marked by abundance of fishes and hence called as age of fishes. 24. (a) 25. (a) The fossils can be define as remains of impressions of the hard parts of the past life-forms in the strata of the earth. Fossils provide one of the most acceptable evidences in support of evolution, because we can study the evolutionary past of individuals in the form of the fossils. The study of fossils is known as paleontology. Their evidence of evolution based on the knowledge of fossils is called paleontological evidence. Living organisms living in various ages and entombed in various starta of rocks provide concrete clues to the variety of life that existed in the past. Age of the fossils can be determined by three methods: (i) Radioactive clock method (ii) Redioactive arbon method and (iii) Potassium organ method. 26. (b) Jurassic period, known as the age of reptiles existed about 145illions years ago. It belongs to the Mesozoic era whichis the era of medieval life (Age of reptiles and gymnosperms). 27. (a) Carboniferous period of palaeozoic era is known as the age of amphibians. It existed about 350 million years ago in which reptiles and winged insects were originated and amphibians were dominant. 28. (b) Australopithecus probably lived in East African grasslands about 2 million years ago. They hunted with stone Weapons essentially ate fruit. They were about 1.5 m high and their brain capacity was about 500 cc. They had bipedal locomotion and erect posture. 29. (c) 30. (a) Azoic era is the era of no life. It existed about 4600 million years ago when only solar system had originated. Page 6 of 6