7

Q1. Which among the following had the smallest cranial capacity?

• 1) Australopithecus
• 2) Pecking man
• 3) Homo sapiens
• 4) Java man

Solution

  Cranial capacity Primate 1200-1600 cm³ Homo sapiens 450-650 cm³ Australopithecus  800-1000 cm³ Java man 900-1000 cm³ Pecking man    

Q2. Swan-necked flask experiment was done by:

• 1) Francesco Redi
• 2) Louis Pasteur
• 3) Robert Koch
• 4) Aristotle

Solution

Louis Pasteur used a special flask whose neck was shaped like an S or the neck of a swan, hence the name ‘Swan Neck Flask.’ He showed that minute organisms, such as protists and bacteria arise from pre-existing organisms.

Q3. Jurassic period of Mesozoic era is characterized by

• 1) Gymnosperms were dominant plants and first birds appear
• 2) Dinosaurs became extinct and angiosperms appear
• 3) Flowering plants and first dinosaurs appear
• 4) Radiation of reptiles and origin of mammal-like reptiles

Solution

Jurassic period of Mesozoic era is characterized by rise of toothed birds, reptiles were dominant, dinosaurs became large and the dominance of gymnosperms (flowering plants).

Q4. According to Lamarckism, long necked giraffe evolved because:

• 1) Short necked suddenly became long necked
• 2) Nature selected only long necked ones
• 3) Humans preferred only long necked ones
• 4) By stretching of necks over many generations

Solution

According to Lamarck, evolution is a gradual process and it occurs by accumulation of changes over generations. Giraffe had to feed on leaves that were the only food available by continuous stretching of neck and forelimbs. This increase in neck length passed on to generations in which further elongation occurred due to similar efforts.

Q5. Cro-magnon man was

• 1) Omnivorous
• 2) Carnivorous
• 3) Herbivorous
• 4) Frugivorous

Solution

All the fossils found for human were carnivores which included Australopithecus africanus, Homo habilis, Homo erectus and Cro-magnon man.

Q6. Among the human ancestors, the brain size was more than 1000 c.c. in

• 1) Ramapithecus
• 2) Homo erectus
• 3) Homo neanderthalensis
• 4) Homo habilis

Solution

Homo neanderthalensis had cranial capacity of 1300-1600 cubic centimeters about the same as that of the modern man which is more as compared to Homo habilis (650-800 cubic centimeters),Homo erectus (800 cubic centimeters) and Ramapithecus (300-350 cubic centimeters).

Q7. What are the end products of the experiment by Miller? 

Solution

Miller found simple organic compounds that included amino acids such as glycine, alanine and aspartic acid.

Q8. Fossils are generally found in:

• 1) Any type of rock
• 2) Metamorphic rocks
• 3) Igneous rocks
• 4) Sedimentary rocks

Solution

Fossils are commonly found in sedimentary rocks. Sedimentary rocks are the most common type of rock since they are formed by the earth's natural forces like wind and water.

Q9. Which one of the following is considered as common ancestor of old world monkeys, apes and man?

• 1) Shivapithecus
• 2) Oligopithecus
• 3) Ramapithecus
• 4) Parapithecus

Solution

The evolutionary lines of monkeys and apes diverged from the earliest fossil to represent the ancestors of monkeys, apes and humans called the Parapithecus.

Q10. The wings of bat and birds are

• 1) Both homologous and analogous
• 2) Analogous
• 3) Vestigeal
• 4) Homologous

Solution

Wings of bats and birds have an ancestral condition leading to the similarity of forelimb structure and so are homologous.

Q11. The concept of chemical evolution is based on

• 1) effect of solar radiation on chemicals
• 2) interaction of water, air and clay under intense heat
• 3) crystalization of chemicals
• 4) possible origin of life by combination of chemicals under suitable environmental conditions

Solution

The concept of chemical evolution was experimented by Urey and Miller which included the combination of chemicals under suitable environmental conditions.

Q12. How many years ago, abiogenesis occurred?

• 1) 2.5 billion years
• 2) 3.2 billion years
• 3) 3 billion years
• 4) 3.5 billion years

Solution

Earth is believed to have formed about 5 billion years ago. 3.5 billion years ago, the atmosphere probably consisted of carbon dioxide (CO2), carbon monoxide (CO), water (H2O), nitrogen (N2), and hydrogen. The “theory of abiogenesis” states that “life originated from non-living matter”.

Q13. Hand of man, wing of bat and flipper of seal represent:

• 1) Analogous organs
• 2) Homologous organs
• 3) Evolutionary organs
• 4) Vestigeal organs

Solution

The forelimbs of man, bats and seal are homologous organs. These forelimbs have same structure and perform different functions such as hand of man is for grasping; wing of bat is for flying and flippers of seal for swimming.

Q14. An isolated population of humans with equal number of blue-eyed and brown-eyed individuals was decimated by an earthquake. Only a few brown-eyed remained to form the next generation. This kind of change in the gene pool is called

• 1) Founder effect
• 2) Bottle neck effect
• 3) Hardy-Weinberg equilibrium
• 4) Blocked gene flow

Solution

Natural calamities like earthquake reduce the size of a population. The brown-eyed individuals formed the next generation though the genetic pool of the small surviving population is not a representative of genetic pool of the original population which is called as bottle neck effect.

Q15. What do you mean by adaptive radiation? 

Solution

It is the evolutionary process in which different species starting from a common point in a geographical area radiate to other geographical areas.

Q16. The first experiment on chemical evolution and origin of life was carried out by:

• 1) Watson and Crick
• 2) Urey and Miller
• 3) Darwin and Wallace
• 4) Beadle and Tatum

Solution

Oparin and Haldane proposed the chemical theory of evolution and origin of life which was later experimented by Urey and Miller. Watson and Crick developed the structure of DNA. Beadle and Tatum proposed hypothesis of “One gene, one enzyme”.   The Darwin-Wallace theory concluded that species as a whole demonstrate descent with modification from common ancestors, and natural selection is the sum of the environmental forces that drive those modifications.

Q17. The scientific name of tiger is

• 1) Equus caballus
• 2) Equus asinus
• 3) Panthera tigris
• 4) Panthera leo

Solution

Scientific name Common name Panthera leo Lion Panthera tigris Tiger Equus caballus Mare Equus asinus Maleass  

Q18. The gas mixture used by Miller in his experiment comprised:

• 1) CH₂, NH₃, N₂, H₂O
• 2) CH₄, NH₃, H₂O, H₂
• 3) CH₄, CO₂, N₂, H₂O
• 4) NH₃, CO₂, H₂O, N₂

Solution

Miller circulated in the glass apparatus a mixture of methane (CH₄₎, ammonia (NH₃₎, water vapour (H₂O) and hydrogen (H₂)forming a mixture of small organic molecules.

Q19. Who demonstrated existence of life in the boiled broth flask?

• 1) Pasteur
• 2) Darwin
• 3) None of these
• 4) Francisco Redi

Solution

Pasteur proved that microorganisms arise from pre-existing microorganisms by experimenting in boiled broth flask that was filled with nutrient broth.

Q20. Which of the following was missing in the Earth’s primary atmosphere?

• 1) O₂
• 2) All of the above
• 3) O
• 4) O₃

Solution

The Earth’s primary atmosphere lacked oxygen and all its forms.

Q21. The Earth’s atmosphere contains what percentage of oxygen?

• 1) 28.26%
• 2) 15.85%
• 3) 0.25%
• 4) 20.95%

Solution

The Earth’s atmosphere consists of 20.95% of oxygen.

Q22. The theory of natural selection had a number of observations. Of these, what can be inferred from the observation of ‘variation’ and ‘struggle of existence’?

• 1) Survival of the fittest
• 2) Stability in population
• 3) Formation of new species
• 4) Rapid multiplication

Solution

From the observation of ‘variation’ and ‘struggle for existence’, we can infer that in the ever changing environment, only the organisms which are best suited for the surrounding and adapted to it survive, i.e. survival of the fittest.

Q23. The phenomenon of "Industrial melanism" shows:

• 1) Induced Mutation
• 2) Geographical isolation
• 3) Reproductive isolation
• 4) Natural selection

Solution

Industrial melanism is an example of natural selection in which it offers protection in the form of camouflage which can resemble to the particular surrounding, replacing light species with dark species.

Q24. Which of the following is formed in Stanley Miller's classic experiment?

• 1) Amino acids
• 2) UV-radiations
• 3) Nucleic acids
• 4) Microspheres

Solution

Urey and Miller showed the synthesis of organic compounds which included amino acids such as glycine, alanine and aspartic acid.

Q25. Convergent evolution of two species is associated with:

• 1) Recent common ancestor
• 2) Different habitats
• 3) Analogous organs
• 4) Homologous organs

Solution

Convergent evolution is the development of different structures evolving for the same function and has similarity. Wings of birds and butterfly do not have similar structures though they perform similar functions. So analogous organs are a result of convergent evolution.

Q26. Which of the following is not a notable feature of the mutation theory put forth by Hugo de Vries?

• 1) Mutations appear suddenly.
• 2) Mutations can occur only in a specific direction.
• 3) Mutations are recurring.
• 4) Mutations are the raw material for evolution.

Solution

According to the mutation theory put forth by Hugo de Vries, mutations can occur in all directions.

Q27. Darwin's theory states that

• 1) Species change morphologically with nature
• 2) Characters are acquired through inheritance
• 3) Affect of environment on evolution
• 4) Nature selects species which can adapt

Solution

The species with the best adaptations to its environment will be the one that will be able to survive and reproduce which is stated by Charles Darwin.

Q28. Industrial melanism is an example of:

• 1) Protective resemblance with the surrounding
• 2) Defensive adaptation of skin against UV-rays
• 3) Drug resistance
• 4) Darkening of skin due to smoke from industries

Solution

The melanization of a population increases the probability that its members will survive and reproduce because it offers protection in the form of camouflage which can resemble to the particular surrounding, replacing light species with dark species.

Q29. State and explain the factors affecting allele frequency in populations. 

Solution

Five factors are known to affect Hardy- Weinberg genetic equilibrium such as genetic drift, gene flow, mutation, non-random mating and natural selection. (i)Genetic Drift- This represents random changes in small gene pools due to sampling errors in propagation of alleles. The bottleneck effect and founder effect are prime examples of genetic drift. (ii)Gene Flow- The movement of alleles into and out of a gene pool is called gene flow. Migration of an organism into different areas can cause the allelic frequencies of that population to increase. (iii)Mutation-These changes in the genome of an organism are an important source of natural selection. (iv) Nonrandom mating-Inbreeding is a popular form of nonrandom mating. Individuals will mate more frequently with close individuals than more distant ones. (v)Natural Selection- Populations vary in the types of individuals and their reproductive success. Those individuals, who leave more offspring behind than others, pass on more of their alleles and have a better success rate in dominating the population.

Q30. Mention how is mutation theory of Hugo de Vries different from Darwin's theory of natural selection. 

Solution

According to Hugo de Vries, new species arise due to single step large mutation whereas according to Darwin, evolution occurs gradually by the method of natural selection.

Q31. There is no life on moon due to absence of:

• 1) Light
• 2) Temperature
• 3) Oxygen
• 4) Water

Solution

Firstly there is no water on the moon which is the first and foremost requirement for the life. Moreover the temperature on the moon is not suitable for the life to exist.

Q32. Modern man differs from apes in:

• 1) Arms shorter than legs
• 2) Wearing of clothes
• 3) Sparse body hair
• 4) Protruding eyes

Solution

Apes had the equal size of arms with that of legs but modern man is having arms shorter than legs which are different from apes.

Q33. Organs that have different embryonic origin but perform similar functions are:

• 1) Homologous organs
• 2) Vestigeal organs
• 3) Atavism
• 4) Analogous organs

Solution

The organs which have same function and are different in fundamental structure and embryonic origin are called analogous organs. The wings of birds and insects are used for flying in air but are different in structure.

Q34. Which one of the following is the most primitive ancestor of man?

• 1) Australopithecus
• 2) Homo neanderthalensis
• 3) Homo habilis
• 4) Ramapithecus punjabicus

Solution

Ramapithecus punjabicus was ape-like primate that lived on the tree and has jaw bones and teeth like those of humans some 15 million years ago who was found to be the most primitive ancestor of man.

Q35. Cranial cavity of man nearly equals to:

• 1) Cro-magnon man
• 2) Australopithecus
• 3) Neanderthal man
• 4) Java ape man

Solution

Cro-magnon man had a cranial capacity (brain size) of 1650 cc about the same as in the living man.

Q36. Man originated in the:

• 1) Pliocene
• 2) Pleistocene
• 3) Palaeocene
• 4) Miocene

Solution

During the Cenozoic era, primitive man originated in the Pleistocene epoch.

Q37. The prehistoric man which lived on earth during late Pleistocene period was:

• 1) Cro-magnon man
• 2) Australopithecus
• 3) Neanderthal man
• 4) Atlantic man

Solution

Homo habilis man started living from the beginning of Pleistocene age and was concluded by Neanderthal man that lived in the late Pleistocene age.

Q38. What is speciation? List any two events leading to speciation. 

Solution

The process involving formation of new species from the existing species is called speciation. Two events leading to speciation are- (i) Interbreeding among different populations or species. (ii) Migration

Q39. An important evidence in favour of organic evolution is the occurrence of the following organs:

• 1) Analogous and vestigeal organs
• 2) Homologous and vestigeal organs
• 3) Homologous and analogous organs
• 4) Homologous organs only

Solution

Homologous and analogous structures reveal a nested hierarchy among all life on Earth that provides evidence in favour of organic evolution.   The hierarchy of organisms shows strong evidence of common descent. Comparing embryos of different animals shows similarities and relationships.

Q40. Animal population within which interbreeding occurs is called:

• 1) Species
• 2) Class
• 3) Family
• 4) Genus

Solution

The breeding of related individuals within an isolated or a closed group of organisms or people occurs among species, which is termed as interbreeding. 

Q41. (p + q)² = p² + 2pq + q² = 1 represents an equation used in:

• 1) biometrics
• 2) population 'genetics
• 3) Mendelian genetics
• 4) molecular genetics

Solution

When p is the frequency of occurrence of dominant allele and q is the frequency of occurrence of recessive allele, the genotype frequency is represented as (p + q) ² = p² + 2pq + q² = 1 in a certain population.

Q42. Convergent evolution is illustrated by:

• 1) Dog fish and whale
• 2) Rat and dog
• 3) Bacterium and Protozoan
• 4) Starfish and cuttle fish

Solution

Convergent evolution is the formation of similar traits by unrelated groups of organisms. Dogfish and whale are the interesting examples of convergent evolution in animals as both of them have more or less similar body organization.

Q43. What does Hardy-Weinberg equation p2 + 2pq + q2 = 1 convey? 

Solution

Hardy- Weinberg equation conveys genetic equilibrium i.e. sum total of all allelic frequencies is 1.

Q44. Which of the following is not a vestigial organ in man?

• 1) Tail vertebrae
• 2) Wisdom tooth
• 3) Vermiform appendix
• 4) Nail

Solution

Vestigeal organs are the organs that occur in reduced form and are useless to the individual but are homologous to the fully developed functional organs. Tail bone, wisdom tooth and vermiform appendix are the vestigial organs that no longer have any role. Nail is the existing organs in the individual

Q45. In the case of peppered moth (Biston betularia), the black-coloured form became dominant over light-coloured form in England during industrial revolution. This is an example of:

• 1) aggressive mimicry
• 2) Natural selection whereby the darker forms were selected
• 3) Protective mimicry
• 4) Appearance of darker-coloured individuals due to very poor sunlight

Solution

Natural selection was the process of selection of darker forms of peppered moth which became dominant over the light coloured moth.

Q46. To create Brussels sprout, which character of Brassica oleracea wasused in artificial selection?

• 1) Terminal buds
• 2) Stem
• 3) Lateral buds
• 4) Leaves

Solution

Brussels sprout was created by artificial selection of plants with modified lateral buds of the plant Brassica oleracea.

Q47. Giraffe has long neck because:

• 1) Due to evolution and adaptation
• 2) Environment is suitable for its long neck
• 3) Their ancestors were long necked
• 4) They have become long due to their need from past

Solution

According to Lamarck, evolution is a gradual process and it occurs by accumulation of changes over generations. Giraffe had to feed on leaves that were the only food available by continuous stretching of neck and forelimbs. This increase in neck length passed on to generations in which further elongation occurred due to similar efforts.

Q48. Which of the following is the correct order of evolutionary history of man?

• 1) Peking man, Neanderthal, Homo sapiens, Cro-magnon
• 2) Peking man, Neanderthal, Homo sapiens, Heidelberg man
• 3) Heidelberg man, Peking man, Neanderthal, Cro-magnon man
• 4) Peking man, Homo sapiens, Neanderthal, Cro-magnon

Solution

Homo erectus or Heidelberg man evolved 1.7 million years ago which is followed by Peking man which is the fossils of Homo erectus. After a gap of 50,000 years came the Homo neanderthalensis called Neanderthal man. The early or fossil modern man is called Cro-magnon man.

Q49. What is the rate of multiplication in Paramecium?

• 1) Four times in 48 hours
• 2) Thrice in 48 hours
• 3) Twice in 48 hours
• 4) Once in 48 hours

Solution

Paramoecium divides at the rate of three times in 48 hours.

Q50. Basis of life is:

• 1) Protein
• 2) Nucleoprotein
• 3) Liquid
• 4) Nucleic acid

Solution

Nucleic acids are essential for every organism for storage, application and transmission of genetic information.

Q51. Ancestors of mammals belong to:

• 1) Ornithischia
• 2) Therapsida
• 3) Chelonia
• 4) Silusidea

Solution

Therapsida includes mammals and their ancestors whose traits are very unique including an erect posture.

Q52. In a random mating population in equilibrium, which of the following brings about a change in gene frequency in a non- directional manner?

• 1) Mutations
• 2) Random drift
• 3) Migration
• 4) Selection

Solution

Random genetic drift refers to the chance fluctuations in gene frequency that arise in finite populations.   If a random mating population suddenly starts to mate non-randomly, this will have no effect on gene frequencies.

Q53. Being all mammals, whale, dolphin, bat, monkey and horse have some common characters but they also show conspicuous differences due to:

• 1) Divergence
• 2) Convergence
• 3) Genetic drift
• 4) Normalisation

Solution

Mammals, whale, dolphin, bat, monkey and horse have different functions but have similar embryonic origin which are said to be homologous organs which is based on divergent evolution.

Q54. Give two examples of biogeographical evidence in favour of evolution. 

Solution

(i) Darwin’s finches (ii) Australian marsupials

Q55. Palaentological evidences for evolution refer to the:

• 1) fossils
• 2) development of embryo
• 3) analogous organs
• 4) homologous organs

Solution

The fossil record is the primary factual evidence for evolution in times past, and evolution is well documented by further evidence.

Q56. Similarity in organisms with different genotypes indicates:

• 1) Macro-evolution
• 2) Micro-evolution
• 3) Divergent evolution
• 4) Convergent evolution

Solution

Different structures have the similarity in structure which performs different functions results in convergent evolution.

Q57. What is theory of spontaneous generation? Name the scientists who dismissed it.

Solution

Theory of spontaneous generation states that living organisms originated abiogenetically from non-living materials at once. This theory was dismissed by Francisco Redi, Lazzaro Spallanzani and Louis Pasteur.

Q58. Explain how homologous organs support the theory of organic evolution. 

Solution

The forelimbs of some animals have similar anatomical structure. They possess humerus, radius, ulna, carpals, metacarpals and phalanges in their forelimbs. For example, forelimbs of man, whales, bats, cheetah indicates that they have common ancestors which supports organic evolution.

Q59. Mesohippus became extinct because of

• 1) Gradual speciation
• 2) Allopatric speciation
• 3) Sympatric speciation
• 4) Phyletic speciation

Solution

Phyletic speciation is the speciation process wherein the new species replaces the old species, but the number of individuals does not increase leading to gradual extinction. A classic example of this is the extinction of Mesohippus which evolved from Eohippus and become extinct. 

Q60. How many moons does Uranus have?

• 1) 8
• 2) 1
• 3) 5
• 4) 3

Solution

Uranus has 5 moons.

Q61. According to Oparin, which one of the following was not present in the primitive atmosphere of earth?

• 1) Oxygen
• 2) Methane
• 3) Water vapours
• 4) Hydrogen

Solution

The most important feature of the ancient environment was the absence of free oxygen.   Evidence of such an anaerobic reducing atmosphere is hidden in early rock formations that contain many elements, such as iron and uranium, in their reduced states. 

Q62. Which one of the following describes correctly the homologous organs?

• 1) Organs which have no function now but had an important function in ancestors
• 2) Organs with anatomical dissimilarities, but performing same function
• 3) Organs appear only in embryonic stage and disappearing later in adult
• 4) Organs with anatomical similarities, but performing different functions

Solution

Organs which look different and perform different functions, having similar basic structure and similar embryonic origin are called homologous organs.

Q63. The theory of spontaneous generation stated that:

• 1) life arose from living forms only
• 2) life can arise from non-living things only
• 3) life arises spontaneously, neither from living nor from the non-living.
• 4) life can arise from both living and non-living

Solution

Theory of spontaneous generation stated that life originated from nonliving materials in a spontaneous manner.

Q64. Life originated from earth's inorganic atmosphere in past but not today. Suggest two reasons. 

Solution

(i) Presence of oxygen (ii) Existence of living organism

Q65. The spread of genes from one breeding population to another by migration which may result in change in gene frequency is:

• 1) Gene flow
• 2) Genetic drift
• 3) None of these
• 4) Gene frequency

Solution

Gene flow is the transfer of alleles from one population to another.

Q66. What is evolution according to Hardy-Weinberg? 

Solution

According to Hardy- Weinberg, the disturbance in genetic equilibrium is the result of evolution.

Q67. Give two Avian and two Reptilian characteristics of Archaeopteryx.

Solution

Archaeopteryx is a missing link between reptiles and birds. Two Avian characteristics of Archaeopteryx are- (i) It possessed feathers, which are exclusively avian structures. (ii) It had rounded cranium with fused bones, jaws modified into a beak, forelimbs modified into wings. Two Reptilian characteristics of Archaeopteryx are- (i) It had teeth in jaws and claws on fingers. (ii) It also had a long tail with free caudal vertebrae and bears tail feathers.

Q68. Darwin's theory does not include

• 1) Survival of the fittest
• 2) Natural selection
• 3) Evolution through inheritance
• 4) Struggle for existence

Solution

Genetic variations are produced by mutations and sexual recombination (molecular inheritance).    This concept was not included in Darwin’s theory.

Q69. What are fossils? Mention any two ways in which the study of fossils supports biological evolution of an organism. 

Solution

Fossils are the remains or impressions of pre-historic organisms preserved in sedimentary rocks. Two ways in which study of fossils supports biological evolution of an organism- (i) The study of Archaeopteryx reveals that birds have evolved from reptiles. This shows fossils provide evidence for evolution. (ii) Phylogeny can be constructed from fossils.

Q70. Mutation theory does not explain:

• 1) Origin of new species
• 2) Connecting link
• 3) Adaptive radiation
• 4) Mimicry

Solution

Mutation theory is the modern concept of evolution which is the major source of genetic variation. It explains about the origin of new species, adaptive radiation and connecting link between two species. But mimicry is not explained in mutation theory.

Q71. The non-directional force that alters Hardy-Weinberg equilibrium is:

• 1) Mutations
• 2) Gene flow
• 3) Gene recombination
• 4) Genetic drift

Solution

When migration of a section of population to another place and population occurs, new genes are added to the new population causing genetic drift. This alters the Hardy- Weinberg genetic equilibrium.

Q72. (a) What is gene migration? (b) Name the phenomenon by which dark coloured moth originated from grey coloured moth 

Solution

(a) When a section of population migrates, it results in addition of new genes or alleles to one population and their loss to another population. This is called gene migration. (b) The phenomenon by which dark coloured moth originated from grey coloured moth is called industrial melanism.

Q73. Among Dryopithecus and Ramapithecus, which one was more man-like?

Solution

First man-like hominid was Ramapithecus.

Q74. Wings of butterfly and bats are:

• 1) Analogous organs
• 2) Homologous organs
• 3) Evolutionary Organs
• 4) Vestigeal and Analogous Organs

Solution

The wings of a bat and a butterfly, both perform the same function of flight aid, but structurally have different origin and hence are considered as analogous organs. 

Q75. The theory of inheritance of acquired characters was put forth in which book?

• 1) Philosphie Botanique
• 2) Philosphie Theories
• 3) Philosphie Zoologique
• 4) Philosphie Evolution

Solution

The theory of inheritance of acquired characters was put forth by Lamarck in his book Philosphie Zoologique.

Q76. The cranial cavity was largest among the:

• 1) Neanderthal man
• 2) Java ape man
• 3) Peking man
• 4) African man

Solution

The fossils of Homo erectus were found in three regions- Java ape man, Peking Man and Heidelberg man. Their brain capacity was 800 to 1300 cubic centimeter. Neanderthal man was found after 50,000 years whose cranial capacity was 1300-1600 cubic centimeter.

Q77. Scientific name of Java man is:

• 1) Australopithecus bisei
• 2) Homo habilis
• 3) Homo erectus erectus
• 4) Homo sapiens neanderthalensis

Solution

Fossils of man found near Java was said to be Java- ape man or Homo erectus erectus.

Q78. Animal husbandry and plant breeding programmes are the examples of

• 1) Mutation
• 2) Natural selection
• 3) Artificial selection
• 4) Reverse evolution

Solution

Farmers and breeders allowed only the plants and animals with desirable characteristics to reproduce, causing the evolution of farm stock which is called as selective breeding or artificial selection.

Q79. What are the key concepts of Darwinian theory of evolution?

Solution

Key concepts of Darwinian theory of evolution are- (i) Branching descent (ii) Natural selection

Q80. The morphological species concept was suggested by

• 1) Davis and Heywood
• 2) Linnaeus
• 3) George Gaylord
• 4) Ernst Mayr

Solution

The morphological species concept was suggested by Davis and Heywood.

Q81. In the Hardy-Weinberg equation (p + q)² = p² + 2pq + q² = 1, 2pq represents

• 1) Frequency of recessive homozygous alleles
• 2) Gene frequency of the total population
• 3) Frequency of dominant homozygous alleles
• 4) Frequency of heterozygous alleles

Solution

In the Hardy-Weinberg equation (p + q)² = p² + 2pq + q² = 1, 2pq is thefrequency of occurrence of heterozygous alleles p² is the frequency of occurrence of homozygous dominant alleles q²is the frequency of occurrence of homozygous recessive alleles

Q82. In which era, reptiles were dominant?

• 1) Coenozoic
• 2) Palaeozoic
• 3) Mesozoic
• 4) Archaeozoic

Solution

During the Mesozoic era, in Cretaceous period, reptiles had become extinct but at the beginning of Jurassic period, reptiles became dominant.

Q83. Give a biological term for single step large mutation.

Solution

Single step large mutation is called as saltation.

Q84. The investigation of life on heavenly bodies other than Earth is known as

• 1) Space expedition
• 2) Alien life investigation (ALI)
• 3) Exobiology
• 4) Alieobiology

Solution

The investigation of life on heavenly bodies other than Earth is known as exobiology.

Q85. The mutation theory was put forth by

• 1) Wallace
• 2) Darwin
• 3) Hugo de Vries
• 4) Lamarck

Solution

The mutation theory was put forth by Hugo de Vries, a Dutch botanist, in1901.

Q86. Connecting link between annelids and molluscs is

• 1) Limulus
• 2) Peripatus
• 3) Neopilina
• 4) Periplaneta

Solution

Neopilina is a connecting link between annelids and molluscs. It is the only segmented mollusc having a pair of shell muscles, gills and auricles.

Q87. Name the period of geological history when lycopod flourished.

Solution

Lycopod were seen in the Jurassic period of Mesozoic Era.

Q88. What do you mean by biogenesis? 

Solution

Biogenesis states that life originates from pre-existing life.

Q89. Marble is formed from

• 1) Granite
• 2) Sea salt
• 3) Lava
• 4) Limestone

Solution

When the sedimentary rock limestone melts and resolidifies, it forms a metamorphic rock called marble.

Q90. Stanley Miller proposed origin of life by:

• 1) Abiogenesis
• 2) Chemical synthesis
• 3) None of these
• 4) Biogenesis

Solution

Chemical synthesis of organic compounds from inorganic molecules proposed the origin of life by Stanley Miller and Harold C. Urey which included a glass apparatus and a mixture of methane, ammonia and hydrogen.

Q91. The difference in the DNA content of chimpanzee and man is about

• 1) 18%
• 2) 28%
• 3) 1.8%
• 4) 58%

Solution

The difference in the DNA content of chimpanzee and man is about 1.8%.

Q92. Cro-Magnon man differs from Neanderthal man in having:

• 1) Large jaws
• 2) Small jaws
• 3) Cannibalism
• 4) Brachiasm

Solution

Cro-Magnon man had large skull, small but strong jaws with teeth closer together, prominent chin.

Q93. Industrial melanism was highlighted in:

• 1) Triticum aestivum
• 2) Biston Betularia
• 3) Mimosa pudica
• 4) Rock python

Solution

Biston Betularia species of peppered moth showed the property of industrial melanism by replacing the light coloured moth with the dark coloured.

Q94. Connecting (should be missing link) link between apes and man is:

• 1) Neanderthal man
• 2) Cro-magnon man
• 3) Australopithecus
• 4) Lemur

Solution

Australopithecus was the first ape-man whose features were similar to modern man like erect posture.

Q95. Which one is present today but was absent about 3 to 5 billion years ago?

• 1) CH₄
• 2) N₂
• 3) O₂
• 4) H₂

Solution

Earth is believed to have formed about 5 billion years ago. 3.5 billion years ago the atmosphere probably consisted of carbon dioxide (CO2), carbon monoxide (CO), water (H2O), nitrogen (N2), and hydrogen. The most important feature of the ancient environment was the absence of free oxygen. Evidence of such an anaerobic reducing atmosphere is hidden in early rock formations that contain many elements, such as iron and uranium, in their reduced states. 

Q96. Geographic and reproductive isolations are most closely associated with:

• 1) Competition
• 2) Extinction
• 3) Succession
• 4) Speciation

Solution

Origin of new species from the existing one is called speciation. Geographical and reproductive isolation are an important factor in formation of new species, when environmental conditions change or migrate to a new area.

Q97. The spark-discharge apparatus to test chemical evolution of life was designed by:

• 1) Dixon and Jolly
• 2) Jacob and Monod
• 3) Oparin and Haldane
• 4) Urey and Miller

Solution

Urey and Miller designed a glass apparatus comprising a gas flask, a condenser and a liquid flask interconnected with tubes and fitted with sources of energy in the form of electric sparks of 75000 V from electrodes in the gas flask.

Q98. What are the various components of human evolution? Give one example. 

Solution

During human evolution, ancestral human types had undergone a number of remarkable changes in their brain size, skeletal features, and dietary preference. For example, Australopithecus had a brain capacity of 450 cubic centimeters and was chinless. It was primarily fruit-feeder but also hunted with stones.

Q99. Hardy-Weinberg operates in the absence of:

• 1) All of these
• 2) Recombination
• 3) Natural selection
• 4) Mutations

Solution

Mutation, Natural selection and recombination do not play any role in Hardy-Weinberg genetic equilibrium.

Q100. Hardy-Weinberg principle explains:

• 1) All of these
• 2) Genetic equilibrium
• 3) Genetic drift
• 4) Chromosomal abberation

Solution

The relative frequency of alleles in the population of sexually reproducing organisms remains constant from generation to generation. So it maintains a genetic equilibrium in the population.

Q101. Are the thorns of Bougainvillea and tendrils of Cucurbita homologous or analogous? What type of evolution has brought such a similarity in them? 

Solution

The thorns of Bougainvillea and tendrils of Cucurbita are homologous organs. Divergent evolution has brought a similarity in them.

Q102. Chemical theory of origin of life was given by

• 1) Spallanzani
• 2) Stanley Miller
• 3) Louis Pasteur
• 4) Oparin and Haldane

Solution

According to chemical theory of origin of life proposed by Oparin and Haldane, there formed the evolution of chemical substances that preceded the actual origin of life.

Q103. Scientist who performed experiment for the prediction of origin of life by using CH₄, NH₃, H₂O and H₂ was:

• 1) A.L. Oparin
• 2) H. Urey
• 3) J.B.s. Haldane
• 4) S. Miller

Solution

S. Miller in association with Harold C. Urey showed the synthesis of organic compounds from inorganic molecules by using methane, ammonia and hydrogen.

Q104. Abiogenesis means

• 1) Origin of panspermia
• 2) Germplasm theory
• 3) Spontaneous generation
• 4) Physico-chemical origin of life

Solution

Abiogenesis is the natural process by which life arose from non-living matter such as simple organic compounds which is a technical term for spontaneous generation.

Q105. According to Hardy- Weinberg's principle, the allele frequency of a population remains constant. How do you interpret the change of frequency of alleles in a population? 

Solution

Change of frequency of allele in a population will result in natural selection leading to the evolution.

Q106. Related species which are reproductively isolated but morphologically similar are called:

• 1) Morphospecies
• 2) Sympatric
• 3) Sibling
• 4) Allopatric

Solution

Sibling species are pairs or groups of genetically closely related species which are morphologically similar but are reproductively isolated.

Q107. (a)What must have provided energy for the warmth for life to originate on primitive earth? Name the first organism to release oxygen into the atmosphere. (b)What do you mean by theory of spontaneous generation? 

Solution

(a)Energy for origin must have been provided by heat, cosmic rays and lightning. The first organism to release oxygen into the atmosphere is Cyanobacteria. (b) Theory of spontaneous generation states that living organisms arose from decaying and rotting matter.

Q108. In which condition, the gene ratio remains constant for any species?

• 1) Mutation
• 2) Gene flow
• 3) Sexual selection
• 4) Random mating

Solution

Mutation cannot occur in Hardy Weinberg equilibrium because the relative frequency of alleles remains constant from generation to generation.

Q109. Name the scientist who disproved spontaneous generation theory. 

Solution

Louis Pasteur disproved spontaneous generation theory. 

Q110. The most apparent change during the evolutionary history of Homo sapiens is traced in:

• 1) Remarkable increase in brain size
• 2) Loss of body hair
• 3) Walking upright
• 4) Shortening of the jaws

Solution

Homo sapiens had a remarkable increase in the cranial capacity (brain capacity) of 1300-1600 cubic centimeters which arose to a superior brain power.

Q111. First mammals occurred in which era period?

• 1) Triassic - Mesozoic
• 2) Tertiary - Coenozoic
• 3) Permian - Palaeozoic
• 4) None of these

Solution

Rise of first dinosaurs and egg-laying mammals occurred in Triassic period of Mesozoic era.

Q112. What is the significance of Archaeopteryx in the study of organic evolution? 

Solution

Archaeopteryx is a connecting link between reptiles and birds. It shows features of both birds and reptiles giving evidence that birds have evolved from reptiles.

Q113. Define natural selection.

Solution

The process by which plants and animals that can adapt to changes in their environment and are able to survive and reproduce is called natural selection. 

Q114. (a)Define natural selection. (b)Differentiate between vestigial organs and atavistic organs. (c)How do Darwin's finches illustrate adaptive radiation?

Solution

(a) The process whereby organisms better adapted to their environment tend to survive and produce more offspring is called natural selection. (b) Vestigial organs are non-functional organs in an organism but were functional in ancestors .Example- Vermiform appendix of man but atavistic organs are those vestigial organs which have become functional. Example- A baby born with a tail. (c) Darwin’s finches are a group of small sized black birds which were first noticed by Darwin on the Galapagos Island. David Lack reported that these finches evolved from a common ancestral type of South American mainland but radiated to different geographical areas and adapted differently in their feeding habits so developing different types of beaks.

Q115. Change in frequency of alleles in a population results in evolution, is proposed in:

• 1) Lamarck's theory
• 2) Hardy-Weinberg principle
• 3) Darwin's theory
• 4) De Vries theory

Solution

In Hardy-Weinberg law, allele frequencies in a population are stable and are constant from generation to generation that causes change in allele population resulting in evolution.

Q116. Why Cro-magnon man is called the extinct representative of modern man?

Solution

Cro-Magnon man had large skull, strong jaws with teeth, wisdom teeth, high forehead, broad flat face, narrow elevated nose which resembles the characteristics of modern man. They also had developed art and have left paintings and carvings in the caves.

Q117. The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because:

• 1) they have biochemical similarities
• 2) they share a common ancestor
• 3) one organism has given rise to another
• 4) they perform the same function

Solution

The bones of forelimbs of whale, bat, cheetah and man share similarities in the pattern of bones of forelimbs. Though these forelimbs perform different functions in these animals, they have similar anatomical structure. Due to homology, they share a common ancestry.

Q118. In the potassium argon technique of determining the age of rocks, which radioactive potassium is used?

• 1) K⁴⁰
• 2) K¹⁰
• 3) K³⁰
• 4) K²⁰

Solution

K⁴⁰ is commonly found in all rocks and has a half-life of 1.3 × 10⁹ years. This radioactive isotope of potassium is used in the potassium-argon dating technique for determining the age of a rock specimen.

Q119. List the two theories of origin of life. 

Solution

(i) Theory of Chemical Evolution (ii) Theory of Abiogenesis

Q120. Miller performed an experiment to demonstrate that organic materials developed from inorganic materials on primitive Earth. In his experiment, he introduced gases such as methane, ammonia and hydrogen, which were present in the Earth’s primitive atmosphere. The ratio in which he introduced these gases (methane:ammonia:hydrogen) was

• 1) 1:2:1
• 2) 2:2:1
• 3) 1:2:2
• 4) 1:1:1

Solution

In his experiment, Miller introduced the gases methane, ammonia and hydrogen in the ratio of 2:2:1 and water vapours at 800°C.

Q121. Which of the following is a connecting link between mammals and reptiles?

• 1) Balanoglossus
• 2) Ornithorhynchus
• 3) Archaeopteryx
• 4) Peripatus

Solution

Duck-billed platypus (Ornithorhynchus anatinus) is the connecting link between reptiles and mammals.

Q122. Fossils formed by the burial of faecal pellets in sedimentary rocks are called

• 1) Coprolites
• 2) Imprints
• 3) Petrified remains
• 4) Impressions

Solution

Fossils  Mode of formation Petrified remains Replacement of tissue by mineral deposits Impressions Remains of fine-grained sediments on which the organism died Imprints Imprints made by organisms while it moves from one place to the other Coprolites Burial of faecal pellets in sedimentary rocks  

Q123. What is speciation? Name two mechanisms of speciation.

Solution

Origin of new species from a pre-existing species is called speciation. Two mechanisms of speciation are- (i) Gradual speciation (ii) Abrupt speciation

Q124.  What is meant by abiotic synthesis? Who proposed the idea and who supported it experimentally? 

Solution

Abiotic synthesis means origin of life from non-living constituents, i.e. chemical evolution of life state that diverse organic molecules were synthesized from inorganic constituents. This idea was proposed by Oparin and Haldane. It was experimentally proved by Urey and Miller.

Q125. How do we compute the age of a fossil?

Solution

We can compute the age of fossil by following methods such as radiocarbon dating, uranium lead-method, potassium-argon method and electro spin resonance method.

Q126. Who proposed the theory of chemical evolution?  

Solution

Oparin and Haldane gave the theory of chemical evolution.

Q127. Why Australopithecus is called African ape-man?

Solution

The fossils of Australopithecus were discovered from the rocks of late Pliocene period in South Africa. It had a number of apes like characters such as small cranial size, long canines etc but was bipedal like man.

Q128. What are the key concepts of Darwinian theory of evolution? 

Solution

(i) Survival of the fittest (ii) Natural selection

Q129. Whose theory was put to test by Miller and Urey and what was the theory? How did their experiment give due to abiotic origin of life on Earth? 

Solution

Urey and Miller tested the theory of Oparin and Haldane, which states that life originated on the Earth through physiochemical processes of atoms combining to form molecules which in turn react to produce inorganic and organic compounds. Urey and Miller created the similar environment in laboratory using glass apparatus and tubes. They took methane, ammonia, hydrogen and water vapour and supplied electron charge using cathode in a closed flask of 75,000V. After a week, it was observed that a number of complex organic molecules have originated such as sugar, nitrogen base and amino acids.

Q130. (a) Name the primates that lived about 15 million years ago. List their characteristic features. (b) (i) Where was the first man-like animal found?       (ii) Write the order in which Neanderthals, Homo habilis and Homo erectus appeared on earth. State the brain capacity of each one of them.     (iii) When did modern Homo sapiens appear on this planet? 

Solution

(a) Primates were Dryopithecus and Ramapithecus that lived 15 million years ago. Their characteristics features were-  (i) They were hairy and walked like gorillas and chimpanzees.  (ii) Ramapithecus was more man-like.  (iii) Dryopithecus was more ape-like. (b) (i)First man-like animal was found in Ethiopia and Tanzania.  (ii) The order of appearance from earliest to the latest is Homo habilis, Homo erectus and Neanderthals.  The brain capacity of Homo habilis is 650-800 cubic centimeters, Homo erectus is 900 cubic centimeters and Neanderthals is 1400 cubic centimeters.  (iii) Modern Homo sapiens appeared between 75,000- 10,000 years ago.

Q131. Define genetic drift. 

Solution

A sudden change in gene frequency by chance alone rather than by natural selection is called genetic drift.

Q132. Name any two vertebrate body parts that are homologous to human forelimbs.

Solution

Wings of birds and forelimbs of horse are homologous to human forelimbs.

Q133. What do you understand by differential reproduction and reproductive isolation? In what context are these terms used?

Solution

The phenomenon in which all organisms who reach reproductive stage reproduce with varying degree of success, some reproduce more offspring and some reproduce only few is called differential reproduction. The phenomenon in which the individual belonging to same species reproduce among themselves to maintain the integrity of species is called reproductive isolation. Differential reproduction and reproductive isolation are used in reference to natural selection.

Q134. List the postulates of Neo-Darwinism.

Solution

The four factors that is present in Neo- Darwinism are- genetic variations, natural selection, speciation and reproductive isolation.

Q135. Are flippers of penguin and dolphin homologous or analogous? What type of evolution has brought such a similarity in them? 

Solution

Flippers of penguin and dolphin are analogous organs. Convergent evolution is a similarity in them.

Q136. Name the common ancestor of the great apes and man

Solution

Dryopithecus and Ramapithecus are the common ancestor of great apes and man.

Q137. What is Hardy-Weinberg principle? 

Solution

It is the principle which states that the relative frequency of alleles in the population of sexually reproducing organisms remain constant from generation to generation.