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NEET Biology: Diversity in the Living World · Chapter 1

The Living World

What to remember

  • Growth, reproduction, metabolism, cellular organisation and consciousness are the features of living things; metabolism and cellular organisation are the true defining features, and metabolism is the one feature shown by all living organisms.
  • Binomial nomenclature, given by Carolus Linnaeus, names an organism with two words: the generic name (capital first letter) and the specific epithet (small first letter), both in italics when printed and underlined separately when handwritten.
  • The taxonomic hierarchy runs Species → Genus → Family → Order → Class → Phylum (Division in plants) → Kingdom; the species is the lowest category and the kingdom is the highest.
  • Taxonomic aids are herbarium, botanical garden, museum, zoological park and key; a herbarium holds dried, pressed and preserved plant specimens on sheets, and a key is based on contrasting characters in pairs called couplets.

What is living?

Living things are different from non-living things in many ways. Some features are shown by all living organisms. Some features are shown only by some. The main features that people list are growth, reproduction, metabolism, cellular organisation and consciousness.

Growth. Growth is an increase in mass and an increase in the number of cells. In plants, growth by cell division occurs throughout life. In animals, growth is seen only up to a certain age, but cell division continues to replace worn cells. Unicellular organisms grow by cell division. Non-living objects such as a mountain or a sand mound also grow, but they grow by accumulation of material on the surface, from outside. Growth in living organisms is from inside. So growth from inside is a living feature, but growth alone cannot be a defining feature, because many living organisms do not grow in a visible way after some time, and non-living objects also increase in size.

Reproduction. Reproduction is the production of new individuals similar to the parents. Organisms such as fungi multiply by spores. Filamentous algae multiply by fragmentation. Planaria can regenerate lost parts. Yeast and Hydra reproduce by budding. In unicellular organisms like bacteria, unicellular algae and Amoeba, reproduction and growth are the same thing, because cell division increases the number of cells and also produces new individuals. Many organisms do not reproduce at all. A mule, a sterile worker bee and an infertile human couple do not reproduce, yet they are alive. So reproduction is not a defining feature of life.

Metabolism. The sum total of all chemical reactions occurring in the body of an organism is called metabolism. Metabolic reactions can be carried out in a test tube using cell-free extracts, and the reactions are then not living, but the same reactions inside a cell are part of a living system. No non-living object shows metabolism. Metabolism is shown by all living organisms, so it is a defining property of life.

Cellular organisation. All living organisms are made of cells, either one cell (unicellular) or many cells (multicellular). The cell is the basic structural and functional unit of life. Organisation in a cell shows a self-regulated pattern of many chemical reactions. This is a defining feature.

Consciousness. All living organisms can sense their surroundings and respond to stimuli such as light, water, temperature, pollutants and other organisms. Plants respond to photoperiod (the duration of light). Human beings are the only organisms aware of themselves, that is, they have self-consciousness. Consciousness in the sense of response to environmental stimuli is a defining feature of living organisms.

FeatureSeen in non-living objects?Defining feature?
GrowthYes, by accumulation from outsideNo
ReproductionNoNo (mule, sterile worker bee do not reproduce)
MetabolismNoYes
Cellular organisationNoYes
Consciousness (response to stimuli)NoYes

A patient in a coma, on a life-support system, is considered living because of brain activity, shown by electrical signals, and metabolism in the body. Metabolic activity, not heartbeat or breathing alone, is taken as the sign of life.

Diversity in the living world

The number of species that are known and described is between 1.7 and 1.8 million. This refers to biodiversity, the number and types of organisms present on earth. Biodiversity includes the variety of plants, animals and microbes in a region.

In India, we use common names for organisms, such as mango, wheat, house fly and man. Common names vary from place to place within a country, and the same common name may be used for different organisms in different places. Hence there is a need for a standard, scientific naming system that is the same all over the world. Scientific names are based on agreed principles and criteria, which are provided in international codes for naming plants and animals.

Need for classification

The number of known organisms is very large, so it is not possible to study each one separately. Classification is the process by which anything is grouped into convenient categories based on some easily observable characters. For example, we easily recognise groups such as plants or animals, and within them, groups such as trees or birds. Classification makes the study of the vast variety of organisms easier and shows the relationships among them.

The scientific term for the process of classification is taxonomy. Taxonomy involves characterisation, identification, classification and nomenclature. Taxonomic studies of the various species of plants and animals are useful in agriculture, forestry, industry and in knowing our bio-resources and their diversity.

Systematics is a broader field. The word comes from the Latin word "systema", meaning systematic arrangement of organisms. Linnaeus used Systema Naturae as the title of his publication. Systematics takes into account the evolutionary relationships between organisms.

TermMeaning
TaxonomyCharacterisation, identification, nomenclature and classification of organisms
SystematicsStudy of diversity of organisms and their evolutionary relationships
BiodiversityThe variety of living organisms on earth
NomenclatureStandardised naming of organisms

Concept of species

Characterisation of an organism means finding its features. Identification means matching these features with those of known organisms. Taxonomists have developed a common system of naming, which they follow. A species is a group of individuals that have fundamental similarities and can interbreed to produce fertile offspring. It is the lowest taxonomic category and the basic unit of classification. The species of different genera are separated by clear differences in structure and reproductive isolation.

Taxonomic categories and hierarchy

Classification is not a single step process. It involves a hierarchy of steps, each step representing a rank or category. Since the category is a part of the overall taxonomic arrangement, it is called a taxonomic category. All categories together constitute the taxonomic hierarchy. Each category, called a unit of classification, is a taxon (plural: taxa). Taxa can indicate a rank, such as a genus or a family.

The obligate categories in descending order are: Kingdom → Phylum (Division for plants) → Class → Order → Family → Genus → Species. The kingdom is the highest category and the species is the lowest. As we move from species to kingdom, the number of common characters decreases and the number of organisms increases. A species has the maximum number of shared characters among its members.

Species. Species is the lowest category. Members share many characters. For example, Panthera leo (lion) and Panthera tigris (tiger) are different species.

Genus. A genus is a group of related species that has more characters in common compared with species of other genera. For example, potato (Solanum tuberosum) and brinjal (Solanum melongena) belong to the genus Solanum. Lion (Panthera leo), leopard (Panthera pardus) and tiger (Panthera tigris) belong to the genus Panthera, which is different from the genus Felis (cat).

Family. A family has a group of related genera with still fewer similarities. Family is characterised on the basis of vegetative and reproductive features of plant species. Among plants, Solanaceae includes the genera Solanum, Petunia and Datura. Among animals, the family Felidae includes Panthera and Felis (cats). The family Felidae is separate from the family Canidae (dog).

Order. Order is an assemblage of related families that exhibit a few similar characters. The similar characters are less in number as compared with different genera and families. Plant families like Convolvulaceae and Solanaceae are included in the order Polymoniales, mainly based on the floral characters. Among animals, the order Carnivora includes families like Felidae and Canidae.

Class. Class includes related orders. For example, the order Primata (monkeys, gorilla, gibbon) comes in the class Mammalia along with the order Carnivora, which includes carnivores such as tiger, cat and dog.

Phylum or division. Classes with a few similar characters are assigned to a higher category called phylum (in animals) or division (in plants). All animals with a notochord and dorsal hollow nerve cord are in the phylum Chordata, which includes classes such as Mammalia, Aves, Reptilia, Amphibia and Pisces. In plants, classes with a few similar characters are placed in a division.

Kingdom. All animals belonging to different classes, having a few common features, are assigned to the highest category, the kingdom Animalia. All plants are in the kingdom Plantae.

The table below shows the categories for four common organisms.

Common nameBiological nameGenusFamilyOrderClassPhylum/DivisionKingdom
ManHomo sapiensHomoHominidaePrimataMammaliaChordataAnimalia
HouseflyMusca domesticaMuscaMuscidaeDipteraInsectaArthropodaAnimalia
MangoMangifera indicaMangiferaAnacardiaceaeSapindalesDicotyledonaeAngiospermaePlantae
WheatTriticum aestivumTriticumPoaceaePoalesMonocotyledonaeAngiospermaePlantae

Binomial nomenclature

This system of providing a name with two components, the generic name and the specific epithet, was introduced by Carolus Linnaeus. It is the standard system of naming for all organisms. Example: Mangifera indica, where Mangifera is the genus and indica is the species epithet.

Naming of plants follows the International Code for Botanical Nomenclature (ICBN). Naming of animals follows the International Code of Zoological Nomenclature (ICZN). These codes ensure that each organism gets one scientific name that is accepted everywhere.

Universal rules of binomial nomenclature:

  • 1. Biological names are generally in Latin and written in italics. They are Latinised or derived from Latin, irrespective of their origin.
  • 2. The first word in a biological name represents the genus and the second word is the specific epithet.
  • 3. Both the words in a biological name, when handwritten, are separately underlined, or printed in italics to indicate their Latin origin.
  • 4. The first word, the genus name, starts with a capital letter, while the specific epithet starts with a small letter. This can be seen in the name of mango, written as Mangifera indica.
  • 5. The name of the author appears after the specific epithet, that is, at the end of the biological name, and is written in an abbreviated form. For example, Mangifera indica Linn. indicates that this species was first described by Linnaeus. The author citation is not italicised.
RuleExample
Genus starts with a capital letterMangifera
Epithet starts with a small letterindica
Both words italicised in printMangifera indica
Both words underlined separately in handwritingMangifera indica
Author name abbreviated, written at the endLinn.

Taxonomic aids

Taxonomic studies need the identification and classification of organisms. Specimens are preserved and kept for study, and information about organisms is stored. These facilities are called taxonomic aids.

Herbarium. A herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets. The sheets carry information about the date and place of collection, English, local and botanical names, family, collector's name and so on. Herbaria also serve as a quick referral system in taxonomic studies. The herbarium sheets are arranged according to a universally accepted system of classification.

Botanical gardens. These have collections of living plants for reference. Plant species in the garden are grown for identification purposes and each plant is labelled with its botanical or scientific name and its family. The famous botanical gardens are at Kew (England), the Indian Botanical Garden at Howrah (India) and the National Botanical Research Institute at Lucknow (India).

Museum. Biological museums have collections of preserved plant and animal specimens for study and reference. Specimens are preserved in the containers or jars in preservative solutions. Plant and animal specimens may also be preserved as dry specimens. Insects are preserved in insect boxes after collecting, killing and pinning. Larger animals such as birds and mammals are usually stuffed and preserved. Museums often have collections of skeletons.

Zoological parks. These 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 behaviour. All animals in a zoological park are provided, as far as possible, the conditions similar to their natural habitats.

Key. A key is another taxonomic aid used for identification of plants and animals based on the similarities and dissimilarities. The keys are based on a contrasting pair of characters called a couplet. Each statement in the key is called a lead. Separate taxonomic keys are required for each taxonomic category such as family, genus and species for identification purposes.

AidWhat it holds or doesExample/Note
HerbariumDried, pressed plant specimens on sheetsInformation on the sheet: date, place, names, collector
Botanical gardenLiving plants, labelledKew; Howrah; Lucknow
MuseumPreserved plant and animal specimensInsects pinned; large animals stuffed
Zoological parkLiving wild animals in conditions like their habitatStudy of food habits and behaviour
KeyContrasting pair of characters (couplet)Each statement is a lead

NEET traps

  • 1. Growth vs defining feature: Non-living objects also grow, by accumulation from outside, so growth is not defining. Metabolism and cellular organisation are defining.
  • 2. Reproduction vs life: Reproduction is not defining, because a mule or a sterile worker bee does not reproduce but is alive.
  • 3. Taxonomy vs systematics: Taxonomy is naming and classifying. Systematics also includes evolutionary relationships.
  • 4. Phylum vs division: Phylum is used for animals; division is used for plants. Both are at the same level.
  • 5. ICBN vs ICZN: ICBN is for plants (botanical); ICZN is for animals (zoological).
  • 6. Italics and author name: The genus and species names are italicised or underlined separately, but the author's abbreviated name is not.
  • 7. Capital letter rule: The genus name starts with a capital letter; the specific epithet starts with a small letter. Writing "mangifera Indica" is wrong.
  • 8. Taxon vs category: A category is a rank (such as family). A taxon is a group at that rank (such as Felidae).
  • 9. Herbarium vs botanical garden: A herbarium keeps dead, dried specimens. A botanical garden keeps living plants.
  • 10. Genus examples: Potato and brinjal are in the same genus Solanum, but lion and cat are in different genera, Panthera and Felis, though both are in the family Felidae.

One-liners

  • 1. Metabolism is the sum of all chemical reactions in the body.
  • 2. Metabolism is shown by all living organisms and by no non-living object.
  • 3. In unicellular organisms, growth and reproduction are the same event.
  • 4. Growth in living organisms is from inside; in non-living objects it is by accumulation from outside.
  • 5. About 1.7 to 1.8 million species have been described so far.
  • 6. Taxonomy covers characterisation, identification, classification and nomenclature.
  • 7. A species is the basic unit of classification and the lowest category.
  • 8. The kingdom is the highest category in the hierarchy.
  • 9. A group of related species forms a genus; Solanum includes potato and brinjal.
  • 10. Man belongs to the genus Homo, the family Hominidae, the order Primata and the class Mammalia.
  • 11. The housefly is Musca domestica of the order Diptera.
  • 12. Wheat is Triticum aestivum of the family Poaceae.
  • 13. Linnaeus introduced binomial nomenclature.
  • 14. In the name Mangifera indica Linn., Linn. is the abbreviated author name.
  • 15. A key works on a pair of contrasting characters called a couplet.

Practice questions

  1. Which of the following features is shown by all living organisms and by no non-living object?

    1. Metabolism
    2. Movement
    3. Reproduction
    4. Growth from outside
    Answer

    A. Metabolism

    Metabolism, the sum of all chemical reactions in the body, is a defining feature of life. Growth and reproduction are not defining features.

  2. Binomial nomenclature, the system of naming with two components, was introduced by

    1. Aristotle
    2. Carolus Linnaeus
    3. Charles Darwin
    4. Robert Whittaker
    Answer

    B. Carolus Linnaeus

    Carolus Linnaeus introduced the two-word system of naming consisting of the generic name and the specific epithet.

  3. The International Code of Zoological Nomenclature (ICZN) provides rules for naming

    1. algae
    2. plants
    3. fungi
    4. animals
    Answer

    D. animals

    ICZN is the code for animals, while ICBN is the code for plants.

  4. Which taxonomic category is the lowest and is the basic unit of classification?

    1. Genus
    2. Family
    3. Species
    4. Class
    Answer

    C. Species

    Species is the lowest category, and a group of related species forms a genus.

  5. A herbarium is best described as a store house of

    1. stuffed birds and mammals
    2. living plants labelled with scientific names
    3. dried, pressed and preserved plant specimens on sheets
    4. preserved animals kept in jars
    Answer

    C. dried, pressed and preserved plant specimens on sheets

    A herbarium holds dried, pressed plant specimens on sheets, with details such as date and place of collection.

  6. Potato (Solanum tuberosum) and brinjal (Solanum melongena) belong to the same

    1. species
    2. genus
    3. class only
    4. kingdom only
    Answer

    B. genus

    Both have the same genus name Solanum, so they are different species of one genus. They also share higher categories, but the genus is the lowest category they share.

  7. In the classification of man (Homo sapiens), the order is

    1. Carnivora
    2. Sapindales
    3. Diptera
    4. Primata
    Answer

    D. Primata

    Man belongs to the order Primata, class Mammalia, phylum Chordata.

  8. In a taxonomic key, each of the two contrasting statements is called a

    1. lead
    2. taxon
    3. couplet
    4. epithet
    Answer

    A. lead

    A pair of contrasting characters is a couplet, and each statement in the pair is a lead.

  9. The housefly, Musca domestica, belongs to the class

    1. Insecta
    2. Diptera
    3. Arthropoda
    4. Mammalia
    Answer

    A. Insecta

    Housefly is placed in class Insecta, phylum Arthropoda, order Diptera.

  10. The family to which wheat (Triticum aestivum) belongs is

    1. Solanaceae
    2. Poaceae
    3. Anacardiaceae
    4. Muscidae
    Answer

    B. Poaceae

    Wheat belongs to the family Poaceae and the order Poales, a monocot.

  11. Panthera and Felis are two genera placed in the family

    1. Canidae
    2. Hominidae
    3. Felidae
    4. Muscidae
    Answer

    C. Felidae

    Panthera (lion, tiger, leopard) and Felis (cat) are in the family Felidae. Dog belongs to Canidae.

  12. Which of the following lists the taxonomic categories correctly from higher to lower rank?

    1. Genus, family, order
    2. Species, genus, family
    3. Order, class, family
    4. Class, order, family
    Answer

    D. Class, order, family

    The sequence from high to low is kingdom, phylum, class, order, family, genus, species.

  13. The Indian Botanical Garden is situated at

    1. Howrah
    2. Kew
    3. Delhi
    4. Lucknow only
    Answer

    A. Howrah

    The Indian Botanical Garden is at Howrah. The garden at Kew is in England and the National Botanical Research Institute is at Lucknow.

  14. In the scientific name Mangifera indica Linn., the abbreviation Linn. represents

    1. the family
    2. the name of the author who first described the species
    3. the specific epithet
    4. the genus name
    Answer

    B. the name of the author who first described the species

    The author name appears at the end, in abbreviated form, and is not italicised.

  15. About how many species of living organisms have been described so far?

    1. about 170,000
    2. about 170 million
    3. about 1.7 to 1.8 million
    4. about 17,000
    Answer

    C. about 1.7 to 1.8 million

    The number of described species is between 1.7 and 1.8 million.

  16. Given below are two statements: Statement I: Growth is a defining feature of life. Statement II: Metabolism is shown by all living organisms.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    D. Statement I is incorrect but Statement II is correct

    Non-living objects also grow by accumulation from outside, so growth is not defining. Metabolism is shown by all living organisms.

  17. Given below are two statements: Statement I: In a biological name, the genus name starts with a capital letter. Statement II: The specific epithet also starts with a capital letter.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    C. Statement I is correct but Statement II is incorrect

    The epithet starts with a small letter, so Statement II is incorrect.

  18. Given below are two statements: Statement I: A herbarium contains living plants for reference. Statement II: A botanical garden has living plants labelled with their botanical names and families.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    D. Statement I is incorrect but Statement II is correct

    A herbarium keeps dried, pressed specimens. A botanical garden has labelled living plants.

  19. Given below are two statements: Statement I: ICBN is the code for naming plants. Statement II: ICZN is the code for naming animals.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    A. Both Statement I and Statement II are correct

    ICBN is botanical and ICZN is zoological.

  20. Given below are two statements: Statement I: Species is the lowest taxonomic category. Statement II: Systematics takes into account the evolutionary relationships between organisms.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    A. Both Statement I and Statement II are correct

    Both are correct. Systematics is broader than taxonomy because it includes evolutionary relationships.

  21. Given below are two statements: Statement I: Order is a higher category than class. Statement II: Genus is a higher category than family.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    B. Both Statement I and Statement II are incorrect

    Class is higher than order, and family is higher than genus, so both statements are incorrect.

  22. Given below are two statements: Statement I: A mule is sterile, so it is not a living organism. Statement II: A mound of sand grows by cell division.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    B. Both Statement I and Statement II are incorrect

    A mule is alive although sterile. A sand mound grows by accumulation from outside, not by cell division.

  23. Which of the following statements are correct? 1. Each statement in a taxonomic key is called a lead. 2. Keys are based on contrasting characters. 3. A herbarium sheet carries no information on the place of collection.

    1. 1 and 2 only
    2. 1 and 3 only
    3. 2 and 3 only
    4. 1, 2 and 3
    Answer

    A. 1 and 2 only

    Herbarium sheets carry the date, place of collection and names, so statement 3 is incorrect.

  24. Given below are two statements: Statement I: In unicellular organisms, growth and reproduction are the same event. Statement II: In animals, growth by cell division occurs throughout life, but in plants it occurs only up to a certain age.

    1. Both Statement I and Statement II are correct
    2. Both Statement I and Statement II are incorrect
    3. Statement I is correct but Statement II is incorrect
    4. Statement I is incorrect but Statement II is correct
    Answer

    C. Statement I is correct but Statement II is incorrect

    In plants, growth by cell division occurs throughout life, while in animals growth is seen only up to a certain age. So Statement II is incorrect.

  25. Which of the following statements are correct? 1. Panthera and Felis are placed in the family Felidae. 2. Potato and brinjal belong to different genera. 3. Man and housefly are both in the kingdom Animalia.

    1. 2 and 3 only
    2. 1, 2 and 3
    3. 1 and 3 only
    4. 1 and 2 only
    Answer

    C. 1 and 3 only

    Potato and brinjal are both in the genus Solanum, so statement 2 is incorrect.

  26. Assertion (A): Metabolism is a defining feature of life. Reason (R): Metabolic reactions occur in all living organisms and in no non-living object.

    1. Both A and R are true and R is the correct explanation of A
    2. Both A and R are true but R is not the correct explanation of A
    3. A is true but R is false
    4. A is false but R is true
    Answer

    A. Both A and R are true and R is the correct explanation of A

    All living organisms show metabolism and non-living objects do not, which is why it is defining.

  27. Assertion (A): Man is placed in the kingdom Animalia. Reason (R): Binomial nomenclature was introduced by Linnaeus.

    1. Both A and R are true and R is the correct explanation of A
    2. Both A and R are true but R is not the correct explanation of A
    3. A is true but R is false
    4. A is false but R is true
    Answer

    B. Both A and R are true but R is not the correct explanation of A

    Both are true, but the system of naming does not explain the placement of man in a kingdom.

  28. Assertion (A): Mango and wheat both belong to the kingdom Plantae. Reason (R): Mango and wheat both belong to the class Dicotyledonae.

    1. Both A and R are true and R is the correct explanation of A
    2. Both A and R are true but R is not the correct explanation of A
    3. A is true but R is false
    4. A is false but R is true
    Answer

    C. A is true but R is false

    Wheat is a monocot placed in class Monocotyledonae, so R is false.

  29. Assertion (A): Reproduction is a defining feature of life. Reason (R): A mule does not reproduce but is a living organism.

    1. Both A and R are true and R is the correct explanation of A
    2. Both A and R are true but R is not the correct explanation of A
    3. A is true but R is false
    4. A is false but R is true
    Answer

    D. A is false but R is true

    Since a sterile organism is still alive, reproduction cannot be defining. A is false and R is true.

  30. Assertion (A): Botanical gardens keep labelled living plants. Reason (R): Herbarium sheets are arranged by a universally accepted system of classification.

    1. Both A and R are true and R is the correct explanation of A
    2. Both A and R are true but R is not the correct explanation of A
    3. A is true but R is false
    4. A is false but R is true
    Answer

    B. Both A and R are true but R is not the correct explanation of A

    Both are true, but the way herbarium sheets are arranged does not explain why gardens keep labelled living plants.

  31. Assertion (A): Systematics is the same as taxonomy and ignores evolutionary relationships. Reason (R): The word systematics comes from the Latin word systema, meaning systematic arrangement of organisms.

    1. Both A and R are true and R is the correct explanation of A
    2. Both A and R are true but R is not the correct explanation of A
    3. A is true but R is false
    4. A is false but R is true
    Answer

    D. A is false but R is true

    Systematics includes evolutionary relationships, so A is false. R is true.

  32. Match List I with List II. List I: a. Herbarium b. Botanical garden c. Museum d. Key List II: i. Couplet ii. Dried and pressed plant sheets iii. Living labelled plants iv. Preserved and stuffed specimens

    1. a-iii, b-ii, c-iv, d-i
    2. a-ii, b-iii, c-i, d-iv
    3. a-iv, b-iii, c-ii, d-i
    4. a-ii, b-iii, c-iv, d-i
    Answer

    D. a-ii, b-iii, c-iv, d-i

    Herbarium: dried pressed sheets; botanical garden: living labelled plants; museum: preserved and stuffed specimens; key: couplet.

  33. Match List I with List II. List I: a. Man b. Housefly c. Mango d. Wheat List II: i. Poaceae ii. Anacardiaceae iii. Hominidae iv. Muscidae

    1. a-iii, b-i, c-ii, d-iv
    2. a-iii, b-iv, c-ii, d-i
    3. a-iv, b-iii, c-ii, d-i
    4. a-iii, b-iv, c-i, d-ii
    Answer

    B. a-iii, b-iv, c-ii, d-i

    Man: Hominidae; housefly: Muscidae; mango: Anacardiaceae; wheat: Poaceae.

  34. Match List I with List II. List I: a. Man b. Housefly c. Mango d. Wheat List II: i. Poales ii. Sapindales iii. Diptera iv. Primata

    1. a-iv, b-ii, c-iii, d-i
    2. a-iv, b-iii, c-i, d-ii
    3. a-iii, b-iv, c-ii, d-i
    4. a-iv, b-iii, c-ii, d-i
    Answer

    D. a-iv, b-iii, c-ii, d-i

    Man: Primata; housefly: Diptera; mango: Sapindales; wheat: Poales.

  35. Match List I with List II. List I: a. Panthera leo b. Solanum tuberosum c. Triticum aestivum d. Musca domestica List II: i. Wheat ii. Lion iii. Housefly iv. Potato

    1. a-ii, b-iv, c-i, d-iii
    2. a-ii, b-iv, c-iii, d-i
    3. a-ii, b-i, c-iv, d-iii
    4. a-iv, b-ii, c-i, d-iii
    Answer

    A. a-ii, b-iv, c-i, d-iii

    Panthera leo is lion; Solanum tuberosum is potato; Triticum aestivum is wheat; Musca domestica is housefly.

  36. Match List I with List II. List I: a. Taxon b. Species c. Taxonomy d. Systematics List II: i. Unit of classification at any rank ii. Group that interbreeds to give fertile offspring iii. Characterisation, identification, classification and nomenclature iv. Study of diversity with evolutionary relationships

    1. a-i, b-ii, c-iv, d-iii
    2. a-ii, b-i, c-iii, d-iv
    3. a-i, b-ii, c-iii, d-iv
    4. a-iv, b-ii, c-iii, d-i
    Answer

    C. a-i, b-ii, c-iii, d-iv

    Taxon: any unit of classification; species: interbreeding group; taxonomy: characterisation to nomenclature; systematics: diversity and evolutionary relationships.

  37. Match List I with List II. List I: a. Man b. Housefly c. Mango d. Wheat List II: i. Monocotyledonae ii. Insecta iii. Dicotyledonae iv. Mammalia

    1. a-iv, b-ii, c-i, d-iii
    2. a-ii, b-iv, c-iii, d-i
    3. a-iv, b-ii, c-iii, d-i
    4. a-iv, b-iii, c-ii, d-i
    Answer

    C. a-iv, b-ii, c-iii, d-i

    Man: Mammalia; housefly: Insecta; mango: Dicotyledonae; wheat: Monocotyledonae.

  38. A mound of sand becomes larger when material is added to its surface from outside. What does this show about growth as a feature of life?

    1. The sand mound is living because it grows
    2. Increase in size alone cannot define a living thing
    3. Growth is always by cell division in non-living things
    4. Growth from outside is a feature of living things
    Answer

    B. Increase in size alone cannot define a living thing

    Non-living objects grow by accumulation from outside. Living growth is from inside, so growth alone is not defining.

  39. A sterile worker bee never reproduces, yet it is alive. What does this show?

    1. Reproduction cannot be a defining feature of life
    2. Worker bees are non-living
    3. Metabolism is absent in the worker bee
    4. Cellular organisation is not needed for life
    Answer

    A. Reproduction cannot be a defining feature of life

    A living organism need not reproduce, so reproduction is not a defining feature.

  40. A botanist writes Oryza sativa L. for rice. Which part of this name is the author citation?

    1. Oryza sativa
    2. sativa
    3. Oryza
    4. L.
    Answer

    D. L.

    The abbreviated author name is placed at the end, after the specific epithet.

  41. An insect collection is being prepared in a museum. How are insects usually preserved?

    1. They are kept alive in a garden
    2. They are dried and pressed on sheets
    3. They are stuffed and displayed in glass cases
    4. They are killed, pinned and kept in insect boxes
    Answer

    D. They are killed, pinned and kept in insect boxes

    Insects are collected, killed, pinned and stored in insect boxes. Large animals such as birds and mammals are stuffed.

  42. Two organisms belong to different genera but to the same family. Which statement is certainly true for them?

    1. They belong to the same genus
    2. They belong to the same order, class, phylum and kingdom
    3. They belong to different orders
    4. They belong to the same species
    Answer

    B. They belong to the same order, class, phylum and kingdom

    Members of one family share all higher categories, namely order, class, phylum and kingdom, but not the genus.

  43. A student wants to identify an unknown plant by choosing between pairs of contrasting characters, step by step. Which taxonomic aid should be used?

    1. Key
    2. Herbarium
    3. Museum
    4. Botanical garden
    Answer

    A. Key

    A key uses couplets of contrasting characters for identification.

  44. Lion, tiger, domestic cat and dog are compared. Which pair shares the largest number of characters?

    1. Lion and dog
    2. Lion and domestic cat
    3. Lion and tiger
    4. Domestic cat and dog
    Answer

    C. Lion and tiger

    Lion and tiger belong to the same genus Panthera, a lower category than the family or order that the other pairs share.

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