NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms

Chapter Name

NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms

Topics Covered

  • NCERT Intext Questions
  • NCERT Exercise Solutions

Related Study

  • NCERT Solutions for Class 9 Science
  • NCERT Revision Notes for Class 9 Science
  • Important Questions for Class 9 Science
  • MCQ for Class 9 Science
  • NCERT Exemplar Questions For Class 9 Science

NCERT Intext Questions

1. Why do we classify organisms?


We classify organisms for easier and convenient study.

2. Give three examples of the range of variations from daily life.


(a) Small cat and big cow
(b) Grass and coconut tree
(c) Black crow and green parrot

3. Which do you think is a more-basic characteristic for classifying organisms?
(a) The place where they live,
(b) the kind of cells they are made of, Why?


(b) The kind of cells they are made of because various organisms can live in a habitat and it is possible that they have no common factor except habitat.
Thus, habitat cannot be basic characteristic for classifying organism.

4. What is the primary characteristic on which the first division of organisms is made?


Nature of cell is primary characteristics for the first division of organisms to decide as prokaryotic or eukaryotic cell.

5. What is the basis on which plants and animals put into different categories ?


Mode of nutrition is the basis on which plants and animal put into different categories.

6. Which organisms are called primitive and how are they different from the advanced organisms ?


Organisms with simple cellular structure and no division of work are called primitive. Advanced organisms are those who have million of cells and there are different organs and organ system for different biological functions.

7. Will advanced organisms be the same as complex organisms ? Why ?


Yes, advanced organisms will be the same as complex organism because advanced organism have undergone increasingly complex body design during evolution time.

8. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista ?


  • Kingdom – Monera : These are prokaryotic in nature an unicellular. These do not have membrane bound nucleus and cell organelles.
    Examples: Mycoplasma and most bacteria.
  • Kingdom – Protista : These organisms are unicellular and eukaryotic. Nucleus and membrane bound other cell organelles are present in this.
    Examples: Protozoa like algae and diatoms.

9. In which kingdom will you place an organism which is single – celled, eukaryotic and photosynthetic ?



10. In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?


Kingdom Monera will have the small number of organisms with a maximum of characteristics in common. And kingdom animalia will have the largest number of organisms.

11. Which division among plants has the simplest organisms ?


Thallophyta or algae.

12. How are pteridophytes different from the phanerogams ?


Difference between pteridophytes and phanerogams





They have naked embryos.

Embryo is present in seed.


Reproductive organs are hidden.

Seed also contains stored food.


Pteridophytes have special tissue for conduction of water.

Phanerogams have well – developed vascular tissue.

13. How do gymnosperms and angiosperms differ from each other ?


Difference between Gymnosperms and Angiosperms





The plants of this group bear naked seeds which further becomes a fruit.

The plants of this group bear seeds enclosed inside an organ.


Many cotyledons are present.

Only one or two Cotyledons are present.


Plants are usually perennial evergreen and woody.

Plants may be annual, biennial, perennial, woody or non – woody.

14. How do poriferan animals differ from coelenterate animals ?


Difference between Poriferan animals and Coelenterate animals


Poriferan animals

Coelenterate animals


They are mostly marine, non –motile and found attached to rocks.

They are exclusively marine animals that either live in colonics or have a solitary life span.


They show cellular level of organisation.

They show tissue level or organisation.


Example : Spongilla

Example : Hydra.

15. How do annelida animals differ from arthropoda?


Difference between Annelida and Arthropoda





They have no distinct heads.

Body is divided into head, thorax and abdomen.


Exoskeletons are absent.

Body is covered by chitinous exoskeletons.


They have no jointed appendages.

They have jointed appendages.


Excretion occurs through nephridia.

Excretion occurs through coxal gland on malpighian tubules.


Respiration occurs through skin or parapodia, e.g. earthworm, aphrodite.

Respiration occurs through tracheae or book lungs, e.g. prawn, cockroach.

16. What are the differences between amphibians and reptiles ?


Difference between Amphibians and Reptiles





Animals that can live on land as well as in water.

Animals that can live in water.


Breathe through gills or lungs.

Breathe through lungs.


They have smooth non – scady exoskeleton.

Waterproof scaly exoskeleton.


Eggs without covering.

Eggs with hard covering.


Example : frog,

Example: snake, crocodile.

17. What are the differences between animals belonging to the ayes group and those in the mammalia group ?


Difference between Mammalia and Ayes





Mammals give birth to their young ones.

Birds lay eggs.


Mammals have only fur or hair.

Birds have feathers.


Mammals have denser bones.

Birds have porons or hollow boncs.


Mammals have paws, hands, and hooves.

Birds have wings.


Mammals produce sound using a larynx.

Birds does not produce sound.


Mammals feed their young ones with milk produced by the mammary glands.

The young birds are fed by the parents regurgitating partially digested food.

NCERT Exercises Solutions

1. What are the advantages of classifying organisms?


Advantages of classification :

  1. Better categorization of living beings based on common characters.
  2. Easier study for scientific research.
  3. Better understanding of human’s relation and dependency on other organisms.
  4. Helps in cross breeding and genetic engineering for commercial purposes.

2. How would you choose between two characteristics to be used for developing a hierarchy in classification?


(a) The character which is of fundamental importance, generally present in large number of organisms is used in raising a higher category.
(b) The character, generally present in smaller number of organism, is used for raising a lower category.

3. Explain the basis for grouping organisms into five kingdoms.


Basis of classification :

  • Number of cells–unicellular or multicellular
  • Layer of cells
  • Presence or absence of cell wall–eukaryotic or prokaryotic
  • Mode of nutrition–autotroph or heterotroph
  • Level of organization–primitive or advanced

4. What are the major divisions in the plantae ? What is the basis for these divisions ?



Basis of Classification


Thallus like body


Body is divided into leaf and stem.


Body is divided into root, stem and leaf.


Seed bearing, naked seeds


Seed bearin, covered seeds

5. How are the criteria for deciding divisions in plants differents from the criteria for deciding the sub – groups among animals ?


In plants, basic body structure is a major criteria based on which Thallophytes are different from Bryophytes. Apart from this absence or presence of seeds is another important criteria. Gymnosperms and Angiosperms are further segregated based on if seeds are covered or not. It is clear that it is the morphological character which makes the basis for classification of plants.
In animals, classification is based on more minute structural variations. So, in place of morphology, cytology forms the basis. Animals are classified based on layers of cells, presence or absence of coelom. Further at higher hierarchy animals are classified based on presence or absence of smaller features, like presence or absence of four legs.

6. Explain, how animals in Vertebrata are classified into further sub-groups?


Vertebrates are divided into five groups, i.e. Pisces, Amphibia, Reptilia, Ayes and Mammalia on the basis of certain characteristics as follows :

  1. Pisces : Exoskeleton of scales, endoskeleton of bone/cartilage, breathing through gills.
  2. Amphibia : Slimmy skin, larvae with gills, lungs in adults.
  3. Reptilia : Exoskeleton in the form of scales, lay eggs outside water.
  4. Ayes : Exoskeleton of feathers, lay eggs outside water, most of them fly in air.
  5. Mammalia : Exoskeleton of air, external ears present, most of them give birth to young ones.

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