THE Living World flash cards

1. 1.What are the two defining (defining/technical) characteristics of living organisms?

   Metabolism and cellular organisation are the defining features. Consciousness (ability to sense and respond to environment) is considered the defining property of living organisms.

   Hint: Think of the properties that cannot be shown by non-living things.

2. 2.Why is 'growth' NOT a defining property of living organisms?

   Because non-living objects (e.g. mountains, boulders, sand mounds) also grow by accumulation of material on the surface. Also, dead organisms do not grow. So growth cannot define life.

   Hint: Both a mountain and a dead log fail this test.

3. 3.How does growth differ in living vs non-living things?

   Living organisms grow from inside (intrinsic, by cell division/increase in cell number and mass). Non-living objects grow by extrinsic accumulation of material on the outer surface.

   Hint: Inside vs outside.

4. 4.In multicellular organisms, growth and reproduction are ___ events.

   Mutually exclusive events. Growth = increase in body mass/cell number; reproduction = producing progeny. In multicellular organisms these are separate.

   Hint: Increase in cell number vs producing offspring.

5. 5.Why is reproduction NOT a foolproof (all-inclusive) defining characteristic of living organisms?

   Because many organisms (e.g. sterile worker bees, mules, infertile human couples) do not reproduce, yet they are living.

   Hint: Sterile bees and mules are still alive.

6. 6.In single-celled organisms, how are growth and reproduction related?

   In unicellular organisms like bacteria, Amoeba, unicellular algae, growth (increase in number of cells) IS reproduction. The two are synonymous.

   Hint: Cell division serves both here.

7. 7.Define metabolism.

   The sum total of all chemical reactions occurring in our body (or in a cell). All living organisms are made of chemicals that are constantly being made and changed into other biomolecules.

   Hint: All the chemical reactions of the body.

8. 8.Is metabolism a defining feature of life? Can it occur outside the body?

   Yes, metabolism is a defining feature of all living organisms without exception. Isolated metabolic reactions carried out in a test tube (in vitro) are neither living nor non-living — but are surely living reactions.

   Hint: No non-living thing shows metabolism; in vitro reactions are 'living reactions'.

9. 9.What is regarded as the most obvious and technically complicated defining feature of living organisms?

   The ability to sense their surroundings/environment and respond to environmental stimuli (consciousness). Stimuli may be physical, chemical or biological.

   Hint: Consciousness / response to stimuli.

10. 10.Give examples of stimuli to which plants and animals respond.

    Organisms respond to light, water, temperature, other organisms, pollutants, etc. Plants respond to light, seasons; humans are the only organisms aware of themselves (self-consciousness).

    Hint: Light, temperature, water, seasons.

11. 11.Which organism is said to be aware of itself, i.e. has self-consciousness?

    Human being is the only organism who is aware of himself/herself, i.e. has self-consciousness.

    Hint: Only one species knows it is thinking.

12. 12.What happens to a patient in coma with respect to the property of consciousness?

    Even a patient lying in coma, supported by machines, is a suspended case — this raises questions since consciousness is the defining property, yet such property may not be outwardly evident.

    Hint: NCERT's example of a difficult case.

13. 13.What is the ultimate property that emerges as a result of interactions of components of an organism?

    Living organisms are self-replicating, evolving, self-regulating interactive systems capable of responding to external stimuli. Cellular organisation of the body is the defining feature of life forms.

    Hint: Self-replicating, self-regulating, responsive.

14. 14.List the key properties shown by all living organisms.

    Growth, reproduction, metabolism, cellular organisation, consciousness (ability to sense and respond), and being self-replicating/self-regulating/evolving interactive systems.

    Hint: Six characteristic features.

15. 15.Which properties (growth, reproduction) are shown but are NOT considered defining features of life?

    Growth and reproduction are characteristic of living organisms but are not defining properties, because there are exceptions (non-living things grow; sterile organisms don't reproduce).

    Hint: Both have exceptions.

16. 16.What is biodiversity?

    The number and types (variety) of organisms present on earth. It refers to the diversity in the living world.

    Hint: Number and types of organisms.

17. 17.Approximately how many species have been described/known so far?

    The number of species that are known and described ranges between 1.7–1.8 million. This is called biodiversity.

    Hint: About 1.7–1.8 million.

18. 18.Why is a scientific/standardised name needed instead of local names?

    Because local (common) names vary from place to place and language to language, causing confusion. A single scientific name recognised universally avoids confusion.

    Hint: Local names differ region to region.

19. 19.What is the process of giving scientific names called, and what does it require?

    Nomenclature — giving standardised names. It is possible only when the organism is described correctly and we know what it is (its correct identification).

    Hint: Naming; requires correct identification first.

20. 20.What is identification in taxonomy?

    Determining that a given organism is the same as (or different from) an already known organism — correctly describing and placing it so it can be named.

    Hint: Is it the same as a known organism?

21. 21.Who provided scientific names for plants and animals, and using which system?

    Scientists have evolved procedures with agreed principles/criteria. For plants: ICBN (International Code for Botanical Nomenclature); for animals: ICZN (International Code of Zoological Nomenclature).

    Hint: ICBN for plants, ICZN for animals.

22. 22.What does ICBN stand for?

    International Code for Botanical Nomenclature — provides agreed principles and criteria for naming plants.

    Hint: Code for naming plants.

23. 23.What does ICZN stand for?

    International Code of Zoological Nomenclature — provides agreed principles and criteria for naming animals.

    Hint: Code for naming animals.

24. 24.What is binomial nomenclature? Who provided it?

    A system of naming with two components — Genus and species. Given by Carolus Linnaeus. It is universally used by biologists all over the world.

    Hint: Two-word naming by Linnaeus.

25. 25.Give the biological name of the mango and identify its parts.

    Mango is Mangifera indica. Here Mangifera = generic name (genus) and indica = specific epithet (species).

    Hint: Mangifera indica.

26. 26.State the universal rules of nomenclature (naming).

    1) Names are in Latin, written in italics. 2) First word = genus (capital first letter); second word = specific epithet (small first letter). 3) When handwritten, both words are separately underlined. 4) Name of author appears after specific epithet, in abbreviated form.

    Hint: Latin, italics, genus capital, species small, underline separately, author name.

27. 27.How is a biological name written and printed?

    Biological names are generally in Latin and written in italics (printed) or underlined separately (handwritten), indicating their Latin origin.

    Hint: Italics when printed.

28. 28.In a binomial name, which word is capitalised and which is not?

    The first word (genus/generic name) starts with a capital letter; the second word (specific epithet/species) starts with a small (lower-case) letter.

    Hint: Genus capital, species small.

29. 29.What does 'Linn.' after a scientific name like Mangifera indica Linn. indicate?

    It is the abbreviated name of the author (Linnaeus) who first described the species. It is written after the specific epithet in abbreviated form.

    Hint: Author who first described it.

30. 30.Define taxonomy.

    The process of classification based on characterisation, identification, nomenclature and classification of organisms. It includes describing, naming and arranging organisms into groups.

    Hint: Characterisation → identification → nomenclature → classification.

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