Important Questions Class 11 Biology Chapter 1 The Living World

Important Questions Class 11 Biology Chapter 1 The Living World

The Living World is Chapter 1 of Class 11 Biology. It explains what makes living things different from non-living things and why we need to classify the huge variety of organisms on earth. The chapter covers biodiversity, the rules for naming organisms (binomial nomenclature), taxonomy and the taxonomic categories from species up to kingdom.

This page gives 12 important questions from The Living World with clear answers prepared by Extramarks experts. The questions cover the features of living organisms, why organisms are classified, taxon, species, the correct order of taxonomic categories and examples of classification. Students can use them for school tests and CBSE (Central Board of Secondary Education) exam revision, and teachers and parents can use them for quick practice.

Q1. Write any four unique features of all living organisms.

Answer: The four unique features of all living organisms are:
Growth
Reproduction
Metabolism and
Consciousness

Q2. What are the main kinds of reproduction?

Answer: The main kinds of reproduction are:

  • Asexual reproduction
  • Sexual reproduction

Q3. Why are living organisms classified?

Answer: Classification is a process of grouping things based on easily observable characters. Classification of organisms is done for various scientific reasons. Some of the main reasons are listed below.

  • Classification helps in the identification of specific organisms from the groups of organisms.
  • It makes the study of organisms convenient.
  • It helps in spotting the similarities and differences among the different groups of organisms.
  • It helps in the study of fossils and evolutionary relationships of organisms.

Q4. Why are the classification systems changing every now and then?

Answer: Millions of living forms exist on the earth that include plants, animals and microorganisms. Out of them, many are known and have been classified by the scientists under suitable groups, but on the other side, many new species are continuously being discovered. Many of these newly discovered species have a new set of characters and to classify them, either a new system of classification should be developed or an older one should be revised. This brings changes in the existing system of classification every now and then.

Q5. What different criteria would you choose to classify people that you meet often?

Answer: We can classify the people we meet often on a various basis such as gender, age range, profession, education, hobbies and common interests.

Q6. What do we learn from the identification of individuals and populations?

Answer: In a diverse country like India, we can learn from the identification of individuals and populations about their native places, tribes, food habits, languages and dialects, clothing, religions, castes, customs, etc.

Q7. Define a taxon. Give some examples of taxa at different hierarchical levels.

Answer: The specific level in the hierarchy of the system of classification of living organisms is called taxon. The following table states the different taxa with an example at different hierarchical levels.

Taxon Example (Human)
Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Primata
Family Hominidae
Genus Homo
Species sapiens

Q8. Can you identify the correct sequence of taxonomical categories?
(a) Species → Order → Phylum → Kingdom
(b) Genus → Species → Order → Kingdom
(c) Species → Genus → Order → Phylum

Answer: Both (a) and (c) are the correct sequence of taxonomical categories. The correct sequence of taxonomical categories is Species, Genus, Family, Order, Class, Phylum/Division, and Kingdom.

Q9. Try to collect all the currently accepted meanings for the word ‘species’. Discuss with your teacher the meaning of species in case of higher plants and animals on one hand, and bacteria on the other hand.

Answer: The various definition of species are:

(i) Species is the group of individual organisms with fundamental similarities such as in their morphology, anatomy and physiology.

(ii) Species is the basic unit of classification where individuals share common characteristics.

(iii) Species is the group of individuals who can interbreed among themselves and are capable of producing fertile offspring. They are reproductively isolated from the other members of the different species.

Since higher plants and animals perform sexual reproduction, their species can interbreed freely among themselves to produce the fertile offspring.

On the other hand, bacteria with common genetic material belong to the same species since they perform asexual reproduction.

Q10. Define and understand the following terms:
(i) Phylum
(ii) Class
(iii) Family
(iv) Order
(v) Genus

Answer: (i) Phylum: Phylum is a taxon consisting of one or more classes that possess correlated characters. It comes just below the kingdom. In plants, classes with similar characters are assigned under division rather than phylum.
(ii) Class: Class is a group of closely related orders. Class lies above order and below phylum. One example of a class is all members of class Mammalia have mammary glands to feed their offspring and have hair on their bodies.
(iii) Family: Family is composed of different genera with less number of similarities as compared to the genus and species level. It lies above the genus and below order. Example: All tiger, lion and leopard belong to the cat family.
(iv) Order: An order is the taxa with the one or more families of organisms that possess some specifically correlated characters that are different from the members of the different orders. It lies above family and below the class. The similar characters in an order are lesser in number as compared to different genera in the included family.
(v) Genus: Genus is a group of related species which has more common characters in comparison to species of other genera. It lies above species and below family. Example: Lion, leopard and tiger belong to the same genus Panthera.

Q11. How is a key helpful in the identification and classification of an organism?

Answer: Key is a taxonomical tool that is made in use for the identification of plants and animals based on the similarities and differences. It is developed on the basis of contrasting characters usually presented in a pair, called couplet, that represents the choice between two opposite characters. The selection of one character in a key leads to the rejection of another character when family, species or genera is identified. For example, the presence or absence of hair is a couplet to identify if the animal is a mammal or not.

Once the family is known, a set of identification key can be used for finding its species and then genus. If the organism is not already recorded, the efforts are made to find its details before giving it a new name.

Q12. Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.

Answer: The taxonomical hierarchy of a plant and an animal is given in the following table.

Taxonomical Hierarchy Mango Human
Kingdom Plantae Animalia
Phylum or Division Angiospermae Chordata
Class Dicotyledonae Mammalia
Order Sapindales Primata
Family Anacardiaceae Hominidae
Genus Mangifera Homo
Species indica sapiens

Related Study Material on Extramarks

Q.1 A plant belongs to genus Aloe and species barbadensis. Mill denotes the name of the scientist who discovered it. Using the above information, identify the correct scientific name of the plant.

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Aloe barbadensis Mill

Q.2 If we move towards the kingdom from the species in a taxonomic hierarchy, the number of similar features will

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The number of similar characters decreases from the lowest rank towards the highest rank.

Q.3 Observe the diagram given below:

Name the method of reproduction depicted in the diagram.

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Binary fission is a type of asexual reproduction wherein a cell divides and gives rise to two identical cells. This method of reproduction does not favour variation as there is no fusion of gametes and only a single parent is involved in this method of reproduction.

Q.4 A small portion of the liver has been transplanted in the body of Kate from her twin sisters body. After the removal of the portion, the remaining liver will function normally in her sisters body. Which characteristic of living organisms is responsible for the survival of Kates sister

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The liver has the maximum capacity of regeneration in mammals. It can regenerate after the injury or surgery. Due to this ability of the liver, it can regenerate back to its full size in both the donor and the recipient.

Q.5 Phototropism demonstrates which two characteristics of living organisms

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Phototropism is the growth of an organism in response to light (external stimuli).

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