Assertion Reason Questions for Biology Chapter 1 The Living World

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Directions: In the following questions, a statement of assertion is followed by a statement of reason.
Mark the correct choice as:
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.

Q.1. Assertion : Botany deals with the study of plants and zoology deals with the study of animals.
Reason : Biology is the study of living beings.

Answer Answer: (a) Biology (Bio-living, logy-science). The study of living beings is called biology. Living beings on earth are mainly classified into two forms-plants and animals. Botany and zoology are the fundamental branches of biology. Word botany has been derived from greek word botane which means pasture or plants and zoology has been derived from word zoo-animals, logosstudy. Theophrastus and Aristotle is called the father of botany and father of zoology respectively

Q.2. Assertion : Study of internal structure is called anatomy.
Reason : It is useful for phylogentic study.

Answer Answer: (b) Anatomy is the study of internal structure which can be observed with unaided eye after dissection. By studying anatomy of large number of organisms, it is useful for knowing phylogenetic similarity (homology) and phylogenetic dissimilarity (analogy).

Q.3. Assertion : The science of classifiying organisms is called taxonomy.
Reason : Systematics and taxonomy have same meaning.

Answer Answer: (c) Taxonomy is the science of identification, nomenclature and classification of organisms. But taxonomy and systematics are different terms. Systematics is the branch of biology that deals with diversity of organisms at every level of classification

Q.4. Assertion : Chemotaxonomy is classifying organisms at molecular level.
Reason : Cytotaxonomy is classifying organisms at cellular level.

Answer Answer: (b) All the members of a species have similar karyotype (cytotaxonomy) – there is similarity in the number, size, shape and behaviour of chromosomes. At the molecular level, there is similarity in the types of proteins, enzymes, hormones and other biochemicals.

Q.5. Assertion: Living organisms are regarded as closed systems.
Reason: Energy of living organisms can not be lost or gained from external environment.

Answer Answer: (d) Living organisms are regarded as open system as energy flow is the key function of an ecosystem.

Q.6. Assertion: Both internal as well as external growth is show by living organisms.
Reason: Living organisms undergo the process known as accretion.

Answer Answer: (d) Living organisms show internal growth due to addition of materials and formation of cells inside the body. Such a method is called intussusception. While, non-living things grow due to addition of similar materials to their outer surface. The process is called accretion.

Q.7. Assertion: Metabolism refers to the sum of chemical reactions that occur within living organisms.
Reason: Metabolic reactions occur simultaneously inside living organisms.

Answer Answer: (b) All living organisms are made of chemicals. These chemicals, small and big, belonging to various classes, sizes, functions, etc., are constantly being made and changed into some other biomolecules. These conversions are chemical reactions or metabolic reactions. There are thousands of metabolic reactions occurring simultaneously inside all living organisms, be they unicellular or multicellular.

Q.8. Assertion: One of the defining property of living organisms is consciousness.
Reason: Human being is the only organism that has self consciousness.

Answer Answer: (b) All living organisms have an inherent ability to sense their surroundings or environment and respond to their environmental stimuli. Plants and animals both respond to the external stimuli. Responses of animals are rapid and can easily be observed because they escape by moving away from the site or environmental stress. The plants, on the other hand, cannot move. They face the stresses and adapt themselves by their slow physiological responses. Human beings are slightly different. They are the only organisms who are aware of themselves, i. e., have self -consciousness.

Q.9. Assertion: Living organisms are self replicating, evolving and self regulating unit.
Reason: These are capable of responding to external stimuli.

Answer Answer: (b) Living beings are objects exhibiting growth, development, responsiveness and other characteristics of life. They have their own specific form and structure. Living organisms exhibit properties such as metabolism, growth, reproduction, consciousness, etc. Thus, living organisms are considered as self replicating, evolving and self regulatory interactive systems capable of responding to external stimuli, sharing a common genetic material to varying degree both horizontally and vertically.

Q.10. Assertion: All organisms reproduce for perpetuation of a population.
Reason: Reproduction is an all inclusive characteristic of living organisms.

Answer Answer: (d) Reproduction is the formation of new individuals of the similar kind. Reproduction is not essential for survival of the individuals. It is required for perpetuation of a population. Many organisms do not reproduce, e.g., mules, sterile worker bees, infertile human couples. Therefore, reproduction is not an all inclusive characteristic of living organism

Q.11. Assertion: Living organisms possess specific individuality with the definite shape and size.
Reason: Both living and non living entities resemble each other at the lower level of organization.

Answer Answer: (b) Both living and non-living entities resemble each other at the lower level of organization.

Q.12. Assertion: The growth in living organisms is from inside.
Reason : Plants grow only upto certain age.

Answer Answer: (c) Growth is the act or process, or a manner of growing; development; gradual increase. It is an exclusive event in majority of the higher animals and plants. In plants, growth occurs continuously throughout their life span and in animal, growth is seen only up to a certain age. In living organisms, growth is from inside. Therefore, it cannot be taken as a defining property of living organisms

Q.13. Assertion: Growth in living organism occurs by division of cells and increase in biomass.
Reason: Growth in living organism occurs by accumulation of material by external agency.

Answer Answer: (d) Accumulation of material by external agency cause extrinsic growth which can not be the feature of living organism.


Q.14. Assertion: Consciousness and response to stimuli can be considered as defining property
of living organism.
Reason: The external environmental stimuli can be physical, chemical or biological.

Answer Answer: (b) All organisms, from primitive prokaryotes to most advanced and complex eukaryotes, are able to sense and respond to environmental factors. The stimuli are perceived by sense organs in higher animals through sensory receptors e.g. eyes, ears, nose. Plants do not possess such sense organs. However, they do respond to external factors such as light, water, temperature, pollutants, other organism, etc. Human beings have an additional facility of self conciousness (awareness of self). Consciousness and response to stimuli are said to be the defining properties of living organisms.

Q.15. Assertion: Reproduction cannot be referred as defining property of living organism.
Reason: There are some living organism that do not reproduce e.g. mules, worker bees, infertile
human, etc.

Answer Answer: (d) A mule is a hybrid of male donkey and female horse. It inherited size and intelligence from the horse and firm footedness, great tolerance and ability to live on rough food from the donkey. However, with all its hybrid vigour, the mule is sexually sterile (i.e. unable to reproduce) and have to be produced every time anew. Honey bees are colonial, social and polymorphic insects. Three types of individuals (castes) are found in the colony of honey bees: (i) Queen which is fertile female. (ii) Drones which are males. (iii) Workers are sterile females and perform various duties of the colony.
A large number of couples are infertile. It means they are unable to produce children inspite of unprotected sexual activities. Thus, inability to conceive or produce children even after unprotected sexual cohabitation is called as infertility

Q.16. Assertion: A living organism is unexceptionally differentiated from a non living structure in the
basis of responsiveness.
Reason: Response to stimuli is a defining property of living organism.

Answer Answer:(a) All organisms from primitive prokaryotes to most advanced and complex eukryotes are able to sense and respond to environmental factors. The stimuli are perceived by sense organs in higher animals through sensory receptors. Consciousness and response to stimuli are said to be the defining properties of living organism.

Q.17. Assertion: In fungi, vegetative reproduction occurs by fragmentation and budding.
Reason: Asexual reproduction in fungi, occurs through formation of asexual spores.

Answer Answer: (b) In fungi, vegetative reproduction occurs by fragmentation, budding (yeast), sclerotia, rhizomorphs, etc. Asexual reproduction occurs through formation of asexual spores such as zoospores, sporangiospores, chlamydospores, oidia, coidia, etc.

Q.18. Assertion : Whittaker’s classification for algae is not acceptable.
Reason : Whittaker grouped algae in different kingdoms.

Answer Answer: (a) In Whittaker’s classification, algae are grouped in three kingdoms – Monera (bluegreen algae), Protista (dinoflagellates, diatoms, euglenoids) and Plantae (red algae, brown algae and green algae). Though plant kingdom of Whittaker is often called metaphyta or multicellular plants, the algae included in this kingdom also contain a number of unicellular and colonial forms. The most accepted classification of algae is given by Fritsch. He classified all algae into 11 classes.

Q.19. Assertion : Systematics is the branch of biology that deals with classification of living organisms.
Reason : The aim of classification is to group the organisms.

Answer Answer: (b) Systematics is related with classification, of organisms. In classification, the organisms are grouped on the basis of their characters or phylogeny, etc.

Q.20. Assertion : To give scientific name to plant, there is ICBN.
Reason : It uses articles, photographs and recommendations to name a plant.

Answer Answer: (a) Anyone can study, describe, identify and give a name to an organism provided certain rules are followed. These rules are formed and standardised by International Code of Botanical Nomenclature (ICBN). It uses articles, photographs and recommendations

Q.21. Assertion: Systematics is defined as the science of diversity of organisms in evolutionary context.
Reason: It includes inter-relationship between organisms.

Answer Answer: (b) Simpson (1961) has defined systematics as the branch of biology that deals with the diversity of organism at every level of classification. It deals with cataloging plants, animals and other organisms into categories that can be named, remembered, compared and studied. Study of only one organism of a group provides sufficient information about the remaining members of that group. It also helps in developing evolutionary relationships with or without the help of taxonomic studies of fossils

Q.22. Assertion: New names in binomial nomenclature are derived from Latin or are latinised.
Reason: Latin is a technical language.

Answer Answer: (c) Binomial nomenclature is the system of providing organisms with appropriate and distinct names consisting of two were taken from Latin and Greek languages. New names are now derived either from Latin language or are latinised. This is because Latin language is dead and, therefore, it will not change in form or spelling with passage of time.

Q.23. Assertion: Both words are separately underlined in binomial nomenclature.
Reason: Underlining indicates their Latin origin.

Answer Answer: (a) Both the words in binomial nomenclature when handwritten, are separately underlined, or printed in italics to indicate their latin origin.

Q.24. Assertion: Classification is necessary to study all living organisms.
Reason: Individuals are grouped into categories in classification.

Answer Answer: (a) It is nearly impossible to study all the living organisms. Classification refers to the process by which individuals are grouped into categories. So, classification makes it possible to study all the living organisms by studying the category wise characteristics

Q.25. Assertion: Binomial nomenclature is system of providing name with two.
Reason: Each name consists first of a specific name and second of a generic name.

Answer Answer: (c) Binomial nomenclature is the system of providing organisms with appropriate and distinct names consisting of two words, first generic and second specific.

Q.26. Assertion: Unicellular green algae were not included in protista by Whitttaker.
Reason: Distinction between unicellular and multicellular organisms is not possible in case of algae.

Answer Answer: (a) Unicellular green algae were not included in protista by Whittaker. Distinction between unicellular and multicellular organism is not possible in case of algae

Q.27. Assertion: ICBN is responsible for giving scientific name to plant.
Reason: It uses articles, photographs and recommendations to name a plant.

Answer Answer:(a) International Code of Botanical Nomenclature (ICBN) is responsible for giving scientific name to plants. It uses articles, photos and recommendations to plant. pool.

Q.28. Assertion : Formation of new species is called speciation.
Reason : The deme has a common gene pool.

Answer Answer: (b) All new species develop from the preexisting species. The phenomenon of development of a new species from preexisting one is called speciation. A species is a collections of demes. The deme is a groups of populations with a common gene pool.


Q.29. Assertion : Phylogeny is the developmental history of a species.
Reason : Species is the basic unit of taxonomy.

Answer Answer: (b) Phylogeny is the developmental history of a species or a group of species. Species is the basic unit of taxonomy. It is a natural population of individuals or group of population which resemble one another in all essential morophological and reproductive characters so that they are able to interbreed freely and produce fertile offspring.

Q.30. Assertion : Taxon and category are different things.
Reason : Category shows hierarchical classification.

Answer Answer: (a) A category is a rank or level in the hierarchial classification of organisms. Taxon is a unit in classification which may represent any level of grouping of organisms based on certain common characteristics. There is some confusion in the use of taxon and category, for example Bryophyta is a taxon while division is a category.

Q.31. Assertion : The hierarchy includes seven obligate categories.
Reason : Intermediate categories are used to make taxonomic positions more informative.

Answer Answer: (b) The hierarchy includes seven obligate categories – kingdom, division or phylum, class, order, family, genus and species. In order to make taxonomic position of species more precise, certain categories have been added to this list. They are called intermediate categories, e.g., subkingdom, superphylum or superdivision, superclass, subclass, superorder, suborder, superfamily, subfamily, tribe, subspecies, variety etc.

Q.32. Assertion :The species is reproductively isolated natural population.
Reason : Prokaryotes cannot be kept under different species on the basis of reproductive isolation.

Answer Answer: (b) The species is genetically distinct and reproductively isolated natural population. Sexual reproduction is absent in prokaryotes and some protists. In such cases, morphological differences, cytotaxonomy and chemo-taxonomy are resorted to.

Q.33. Assertion: There are some similarities between cats and dogs.
Reason: Cats and dogs belong to the same family Canidae.

Answer Answer: (c) Family is a group of related genera with still less number of similarities as compared to genus and species e.g., a cat and a dog, have some similarities and some differences as well. They are separated into two different families – Felidae and Canidae, respectively.

Q.34. Assertion: Order is a taxonomic category that includes one or more genera.
Reason: All the genera in an order have some similar features and correlated characters.

Answer Answer: (d) Family is a taxonomic category which contains one or more related genera. All the genera of a family have some common features or co-related characters. Whereas, order includes one or more related families

Q.35. Assertion: Whittaker’s classification for algae is not acceptable.
Reason: Whittaker grouped algae in different kingdoms.

Answer Answer: (a) R.H. Whittaker (1969), an American Taxonomist, classified all organisms into five kingdoms: Monera, Protista, Fungi, Plantae and Animal. Plantae includes green algae, brown algae, red algae, bryophytes, pteridophytes, gymnosperms and angiosperms.

Q.36. Assertion: The hierarchy includes seven obligate categories.
Reason: Intermediate categories are used to make taxonomic positions more informative.

Answer Answer: (b) Taxonomy is based on a hierarchy of classification; the lower you go in the hierarchy, the more closely related the living things are. These groups, from largest to smallest are Kingdom, Phylum, Class, Order, Family, Genus, and Species. Intermediate categories are used to make taxonomic positions more informative.

Q.37. Assertion: Bacteria, Protista do not have circulatory system.
Reason: These organisms live in moist and watery environment.

Answer Answer: (b) In animals that do not contain a circulatory system, the transport of substances occurs by cell to cell diffusion. Bacteria, Protista do not have circulatory system. These organisms live in moist and watery environment.

Q.38. Assertion: The scientific terms for the categories like dogs, cats, mammals, plants, animals etc. is taxa.
Reason: The taxa can indicate categories at very different level.

Answer Answer: (a) To study the organism dogs, cats, mammals, wheat, rice, plants, animals, etc. are convenient categories. Plants, animals, mammals, dogs, etc. all are taxa, which represent taxa at different levels.


Q.39. Assertion: The family Solanaceae includes a number of genera like Solanum, Petunia, Atropa, etc.
Reason: Family contains one or more related genera.

Answer Answer: (a) Family is a taxonomic category which contains one or more related genera. All the genera of a family have some common features and they are separable from genera of a related family by important characteristics. The family Solanaceae includes a number of genera like Solanum, Petunia, Atropa, etc. due to certain similarities.

Q.40. Assertion: Species constitute a group of individuals with fundamental similarities.
Reason: Indica, leo, tuberosum represent such group of individuals.

Answer Answer: (b) Species refer to a group of organisms with fundamental similarities. A species is distinguished from the other closely related species based on distinct morphological differences. e.g., Mangifera indica (Mango), Solanum tuberosum (potato) and Panthera leo (lion). Therefore, all the three names, indica, tuberosum and leo, represent the specific epithets, while the first words Mangifera, Solanum and Panthera are genera.

Q.41. Assertion: Flora contains the actual account of habitat and distribution of plants of a given area.
Reason: Monographs contain detailed information on any taxon.

Answer Answer: (b) Floras, manuals, monographs, etc. are some important taxonomic aids that help in the correct identification. Flora provide the index to the plant species found in a particular area. Manuals are useful in providing information for identification of names of species found in an area. Monographs have information of any taxon.

Q.42. Assertion: Botanical gardens are grown for educational and scientific purposes.
Reason: Zoological parks are the places where wild animals are kept in protected environments.

Answer Answer: (b) Botanical gardens are sufficiently large sized tracts where plants of various types and areas are grown for scientific and educational purposes. Zoological parks are the places where wild animals are kept in protected environments under human care and which enable us to learn about their food habits and behavior.

Q.43. Assertion: Herbarium sheets carry a label.
Reason: Label provides information about data and place of collection.

Answer Answer: (a) A herbarium is a collection of preserved plant specimens and associated data used for scientific study. It carries a label. It provides information about data and place of collection.

Q.44. Assertion: Herbarium is also known as “Dry garden”.
Reason: It is a collection of plant parts that have been dried, pressed, preserved on sheets.

Answer Answer: (a) Herbarium is also known as “Dry garden”. It is a collection of plant parts that have been dried, pressed and preserved on sheets. The procedure of pressing and drying specimens for storage has been an amazingly successful one in terms of preservation of detail and specimen longevity, and the plants so preserved provide a concrete basis for past, present and future studies.

Q.45. Assertion: Keys are analytical in nature.
Reason: These are based on couplet.

Answer Answer: (b) Key is a taxonomical aid used for identification of plants and animals based on the similarities and dissimilarities. The keys are based on contrasting characters generally in a pair called couplet. Keys are generally analytical in nature.

Q.46. Assertion: Information for identification of names of species is provided by monographs.
Reason: Monographs contain information on more than one taxon.

Answer Answer: (d) Manuals are useful in providing information for identification of names of species found in an area. Monographs contain information on any one taxon.


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