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Origin and Evolution of life Class 12 Biology Chapter 5 Questions And Answers Maharashtra Board

Q. 1. Multiple choice questions. 1. Who proposed that the first form of life could have come from pre- existing nonliving organic molecules?a. Alfred Wallaceb. Oparin and Haldanec. Charles Darwind. Louis Pasteur Answer. (b) Oparin and Haldane 2. The sequence of origin of life may be a. Organic materials- inorganic materials – Eobiont- colloidal aggregates- cell.b. Inorganic materials – organic materials – colloidal aggregates – Eobiont- cell.c. Organic materials- inorganic materials – colloidal aggregates – celld. Inorganic materials- organic materials – Eobiont- colloidal aggregates – cell Answer. (b) Inorganic materials – organic materials- colloidal aggregates – Eobiont – cell. 3. In Hardy-Weinberg equation, the frequency of homozygous recessive individual is represented by-(a) p²(b) pq(c) q²(d) 2pq Answer. (c) q² 4. Select the analogous organs a. Forelimbs of whale and batb. Flippers of dolphins and penguinc. Thorn and tendrils of bougainvillea and cucurbita.d. Vertebrates hearts or brains. Answer. (b) Flippers of dolphins and penguin 5. Archaeopteryx is known as missing link because it is a fossil and share characters of both a. Fishes and amphibiansb. Annelida and arthropoda.c. Birds and reptilesd. Chordates and nonchordates. Answer. (c) Reptiles and birds 6. Identify the wrong statement regarding evolution.a. Darwin’s variations are small and directional.b. Mutations are random and nondirectional.c. Adaptive radiations leads to divergent evolution.d. Mutations are non- radamon and directional. Answer. (d) Mutations are non-random and directional 7. Gene frequency in a population remain constant due to –a. Mutationb. Migrationc. Random matingd. Non- random mating Answer. (c) Random mating 8. Which of the following characteristic is not shown by the ape?a. Prognathous faceb. tail is presentc. Chin is absentd. forelimbs are longer than hind limbs Answer. (b) Tail is present 9. ……………… can be considered as conncting link between between ape and man.a. Austalopithecusb. Homo hablisc. Homo erectusd. Neanderthal man. Answer. (a) Australopithecus 10. The Cranial capacity of Neanderthal man was ……………….(a) 600 cc(b) 940 cc(c) 1400 cc(d) 1600 cc Answer. (c) 1400 cc Q. 2. Very short answer question. 1. Define the following terms– a. Gene pool Answer. The sum total of genes of all individuals of interbreeding population or Mendelian population is called gene pool. b. gene frequency Answer. The proportion of an allele in the gene pool as compared with other alleles at the same locus is termed as gene frequency. c. Organic evolution Answer. Organic evolution can be defined as slow, gradual, continuous and irreversible changes through which the present-day complex forms of the life developed (or evolved) from their simple pre-existing forms. d. Population Answer. All individuals of the same species form a group which is called a population. e. Speciation Answer. Formation of new species from the pre-existing single group of organisms is called speciation. 2. What is adaptive radiation? Answer. The process of evolution which results in transformation of original species to many different varieties is called adaptive radiation. 3. If the variation occur in population by chance alone and not through natural selection and it brings change in frequencies of an allele. What is it called? Answer. If the variation occurs in population by chance alone and not by natural selection to bring change in frequencies of an allele, it is called genetic drift. 4. State the Hardy – Weinberg eqnilibrium. Answer. The Hardy-Weinberg equilibrium law states that at equilibrium point both the allelic frequency and genotypic frequency remain constant from generation to generation, in the diploid, sexually reproducing, large, free interbreeding population in which mating is random and there is absence of any other factors that change the allele frequency. 5. What are homologous organs? Answer. Homologous organs are those organs, which are structurally similar but perform different functions. 6. What is vestigeal organ? Answer. Vestigial organs are imperfectly developed and non-functional organs which are in degenerate form, they may be functional in some related and other animals or in ancestor. 7. What is the scientific name of modern man? Answer. Homo sapiens sapiens is the scientific name of modern man. 8. What is coacervate? Answer. Coacervates are colloidal aggregations of hydrophobic proteins and lipids which grew in size by taking up material from surrounding aqueous medium. 9. Which period is known as “age of Reptilia”? Answer. Jurassic period from Mesozoic era is known as age of Reptilia. 10. Name the ancestor of human which is described as man with ape brain. Answer. Australopithecus, the ancestor of human which is described as man with ape brain. Q. 3. Short answer question. 1. Write a note on Genetic drift. Answer. 2. Enlist the different factors that are responsible for changing gene frequency. Answer. Gene flow, genetic drift, gene mutations, chromosomal aberrations such as deletion, duplication, inversion and translocation, genetic recombinations, natural selection, isolation are some of the factors which are responsible for changing the gene frequency. 3. Draw a graph to show that natural selection leads to disruptive change. Answer. 4. Give the significance of fossils. Answer. 5. Write the objections to Mutation theory of Hugo de vries. Answer. Objections to Mutation Theory: 6. What is disrruptive selection? Give example. Answer. Disruptive selection: Example of disruptive selection:African seed cracker finches are types of seed-feeder birds which have different sizes of beak. The seeds available to them were of small and large sized. Large beak sized birds feeds on large seeds while small beak sized birds feed on small seeds. Such large and small birds thus thrive well. However, intermediate beak sized birds are unable to feed on either type of seeds so they starve and their population was decreased gradually. Natural selection eliminated them and thus the population of finches appear disrupted. Q. 4. Match the following. Answer. Column I Column II (1) August Weismann (b) Germplasm theory (2) Hugo de Vries (a) Mutation theory (3) Charles Darwin (d) Theory of natural selection (4) Lamarck (c) Theory of acquired characters Q. 5. Long answer questions. 1. Would you consider wings of butterfly and bat as homologous or analogous and why? Answer. Wings of butterfly are made up of chitin. They neither have bones,