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

NCERT Solutions for Class 9 Science Chapter 7 Diversity in the Living Organisms provides detailed answers for all in-text and exercise Questions. These solutions contain an in-depth explanation of each topic involved in the chapter. Students studying in class 9 can access these solutions for free in PDF format.

All these solutions are prepared by expert teachers and updated for the current academic session. NCERT Solutions for Class 9 Science Chapter 7 Diversity in the Living Organisms help students to understand the fundamental concepts given in class 9 Science textbook. We have prepared the answers to all the questions in an easy and well-structured manner. It helps students to grasp the chapter easily.

NCERT Class 9 Science Chapter 7 Diversity in the Living Organisms Intext Questions (Solved)

PAGE NO. 81

Question 1: Why do we classify organisms?

Answer: There are millions of species on this earth. For anybody, it is impossible to study about each of them in his lifetime. Classification makes it easy to study the organisms; on the basis of certain common characters.

Question 2: Give three examples of the range of variations that you see in life forms around you.

Answer 2:  Three examples of the range of variations in life forms:      

(a) Ants, cockroaches, spiders, houseflies, etc. live in the same building. They look entirely different from each other yet all of them belong to Arthropoda.

(b) Humans, monkeys, cats and dogs lives in the same neighbourhood. They look entirely different yet all of them belong to Mammalia.

(c) A nearby park may show a wide variety of plants; right from small grass to a giant banyan tree.

PAGE NO. 82

Question 1: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?

Answer: The kind of cells an organism is made of is a more basic characteristic of classifying organism because it gives a scientific angle to classification. Moreover, a particular dwelling place can be full of organisms of a wide variety.

Question 2: What is the primary characteristic on which the first division of organisms is made?

Answer: Organisation of the nucleus is the primary characteristic on which the first division of organisms is made. Based on this, organisms can be either prokaryotic or eukaryotic.

Question 3: On what bases are plants and animals put into different categories?

Answer: Plants are autotrophs, while animals are heterotrophs. Cell wall is present in plant cells, while it is absent in animal cells. Plants do not need to move from one place to another, while most of the animals need to move in search of food.

PAGE NO. 83

Question 1: Which organisms are called primitive and how are they different from the so-called advanced organisms?

Answer: An organism which is simple is called primitive. On the other hand, an organism with high level of division of labour, by formation of organs and organ system is called advanced.

Question 2: Will advanced organisms be the same as complex organisms? Why?

Answer: Complexity in body design evolves because of necessity to adapt according to the changing environment. Hence, a complex organism would be an advanced one; in comparison to a simple organism.

PAGE NO. 85

Question 1: What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?

Answer: Organisms which are prokaryotes belong to the kingdom Monera. On the other hand, organisms which are eukaryotes and unicellular belong to the kingdom Protista.

Question 2: In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic?

Answer: Plant Kingdom

Question 3: 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?

Answer: Species will have the smallest number of organisms with a maximum of characteristics in common. On the contrary, kingdom will have the largest number of organisms.

PAGE NO. 88

Question 1: Which division among plants has the simplest organisms?

Answer: Thallophyta.

Question 2: How are pteridophytes different from the phanerogams?

Answer:

PteridophytesPhanerogams
In pteridophytes, the reproductive organs are hiddenIn phanerogams, the reproductive organs are conspicuous
they do not produce seedsthey produce seeds.

Question 3: How do gymnosperms and angiosperms differ from each other?

Answer: Seeds are naked in gymnosperms, while they are covered in angiosperms. Gymnosperms do not bear flowers, while angiosperms bear flowers.

PAGE NO. 94

Question 1: How do poriferan animals differ from coelenterate animals?

Answer:

PoriferaCoelenterata
In Porifera, body has numerous pores,Body pores are absent in coelenterates
Body cavity absent.Body cavity present.
Animals from Porifera show a cellular level of organisationCoelenterata show tissue level of organisation.
Porifera do not have coelomcoelenterata have coelom.

Question 2: How do annelid animals differ from arthropods?

Answer 2:

AnnelidaArthropoda
The entire body is segmented into ringsSegmentation of body into head, abdomen and the thorax region
Skeleton is absentExoskeleton is present.
HermaphroditesPresence of different sexes, bisexual present

Question 3: What are the differences between amphibians and reptiles?

Answer:

AmphibiaReptilia
Skin is moist and softSkin is hardened
In water, they breathe through their skinCan exist in water. They come to land to intake oxygen
Respire through lungs or skinsRespire through lungs
Capable of jumpingThey crawl
Amphibians need water to lay eggsReptilians do not need water to lay eggs
fertilization is externalfertilization is internal

Question 4: What are the differences between animals belonging to the Aves group and those in the mammalian group?

Answer:

AvesMammalia
Body is covered with feathersBody is covered with hairs
Teeth absentTeeth present
Mammary glands are absentaves while present in mammals. 
They possess a beakBeak absent
Forelimbs are modified into wingsForelimbs are present and used for multiple activities
Aves are oviparousMost of the mammals are viviparous
Bones are hollowBones are solid
Body is streamlinedStreamlining of body is not observed(except whales)

NCERT Class 9 Science Chapter 7 Diversity in the Living Organisms Exercise Questions (Solved)

Question 1: What are the advantages of classifying organisms?

Answer 1: There are millions of species on this earth. For anybody, it is impossible to study each of them in his lifetime. Classification makes it easy to study the organisms; on the basis of certain common characters. Further Classification has the following advantages:

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

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

Answer: We need to look at the fact if given character is present in a small number of organisms or a larger number of organisms. In the first case, the commonality of characters would represent a species. In the latter case, the commonality of characters would represent a higher taxa; like genus, family, order or phylum.

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

Answer: he following factors govern the basis of grouping organisms into five kingdoms:
(a) Number of cells
(b) Layer of cells
(c) Presence or absence of cell wall
(d) Mode of nutrition
(e) Level Of organization

Question 4: What are the major divisions in the Plantae? What is the basis for these divisions?

Answer 4: The major divisions of Plantae and the basis for these divisions are as follows:

Thallophyta: Simple body design; with no differentiation into root, stem and leaves.
Bryophyta: Body is differentiated into stem and leaf-like structures. Vascular system is absent.
Pteridophyta: Body is differentiated into root, stem and leaves. Vascular system is present. Reproductive organs are inconspicuous. Seeds are not produced.
Gymnosperms: Seeds are naked.
Angiosperms: Seeds are covered.

Question 5: How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?

Answer:  In the plant kingdom, morphological characters are taken into consideration while deciding about the divisions. Morphology is the study of shapes and forms of various parts. In the animal kingdom, anatomical characters are taken into consideration while deciding about subgroups. Anatomy is the study of various organs’ design in animals.

Question 6: Explain how animals in Vertebrata are classified into further subgroups.

Answer: Vertebrata is divided into two superclasses namely

  • Pisces
  • Tetrapoda

Pisces: The body is streamlined. Muscular tail is present which assists in locomotion. Body is covered with scales. Paired gills are present; which can breathe oxygen dissolved in water. They are cold-blooded animals. The heart has only two chambers. They lay eggs.

Tetrapoda: Animals have four limbs for locomotion and hence the name tetrapoda.

Tetrapoda is divided into four classes, viz. amphibia, reptilia, aves and mammalia.

(a) Amphibia: These animals are adapted to live both in water and land. Mucous glands on skin keep the skin moist. The animals breathe through the skin when in water and through the lungs when on land. The heart has three chambers. These are cold-blooded animals. Examples: Frog, toad, salamander, etc.

(b) Reptilia: These animals show crawling movement for locomotion. Skin is hardened to form scales. Most of the reptilians have three-chambered heart but crocodile has four-chambered heart. They don’t need water to lay eggs, rather eggs are covered with hard shells and laid on land. Examples: snakes, lizards, crocodile, turtle, etc.

(c) Aves: The body is covered with feathers. Forelimbs are modified into wings. These are warm-blooded animals. The heart has four chambers. Bones are hollow (pneumatic); which assists in flying. All the birds belong to this class.

(d) Mammalia: The body is covered with hairs. The skin has sweat glands and sebaceous glands. Mammary glands are present in females and are used for nourishing the young ones. Most of the mammalians give birth to young ones and are called viviparous. Some of the mammals lay eggs and are called oviparous. Examples: human, chimpanzee, lion, platypus, horse, etc.

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