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

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Updated at 2021-04-12


NCERT solutions for class 9 Science Chapter 7 Diversity In Living Organisms Exercise Questions

Q1 ) What are the advantages of classifying organisms?



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


Answer :


(i) Classification helps in exploring the diversity of life forms.

(ii) It simplifies to study them for scientific research.

(iii) It helps in cross breeding and modification for commercial purpose.

(iv) It helps in interpreting the interrelation of humans with other organisms.

(v) It helps in studying the dependence and interactions between different organisms.

Q2 ) How would you choose between two characteristics to be used for developing a hierarchy in classification?



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


Answer :


The basis of the start of the hierarchy will be formed on the basis of the fine character.

1. Human beings are categorized under vertebrates as they possess the vertebral column.

2. Tetrapod is categorized on the basis of the existence of four limbs.

3. Mammals are categorized on the basis of presence of the mammary glands.

Q3 ) Explain the basis for grouping organisms into five kingdoms.



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


Answer :

The major characteristics which is considered for classifying all organisms into five major kingdoms are:

(a) On the basis of their structure and presence or absence of a well developed nucleus and membrane bound cell-organelles, i.e., prokaryotic and eukaryotic organisms.

(b) On the basis of presence of the number of cells which differentiates them into unicellular and multicellular organisms.

(c) On the basis of the presence of a cell-wall which differentiates them into plant cell and animal cell.

(d) On the basis of their mode of nutrition which differentiates them into autotrophs and heterotrophs.

(e) On the basis of their level of complexity of cell which categorizes them into cellular level of organization, tissue level of organization, organ level of organization and organ-system level of organization.

Q4 ) What are the major divisions in the Plantae? What is the basis of these divisions?



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


Answer :



Thallophyta

Bryophyta

Pteridophyta

Gymnosperm

Angiosperm

It has a simple body design and is not differentiated into root, stem and leaves.

Its body is differentiated into stem and leaf-like structures but the vascular system is absent.

Its body is differentiated into root, stem and leaves and also have a vascular system, but the reproductive organs are inconspicuous with no seeds.

They have reproductive organs where the seeds are naked as they don't have any protective covering.

They have reproductive organs where the seeds are covered.

Q5 ) How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?



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


Answer :

Plants are classified based on their morphological characteristics such as :-
On the basis of their cell structure they are classified as thallophytes, bryophytes and pteridophytes.
On the basis of their visibility of seeds they are classified as gymnosperms and angiosperms.

Animals are classified on the basis of their structural variations which are taken into account such as the levels of organization, body symmetry, germinal layers, nature of coelom, segmentation and presence of notochord.

Q6 ) Explain how animals in Vertebrata are classified into further subgroups.



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


Answer :

Vertebrata has two main subclasses namely,
Pisces ( which have a streamlined body with tails and fins that helps them in swimming) and tetrapod ( which have four limbs for their movement).

The tetrapod animals are further classified into:

1. Amphibia : The animals belonging to this group are adapted to live in both land and water. They can breathe under the water through their skin and can breathe through the lungs when they are present on the land. They are cold-blooded and require an aquatic habitat to lay eggs. These organisms are mainly characterized by the presence of two pairs of limbs, smooth and moist skin for respiration.

2. Reptilia : The organisms of this group crawls for their movement. They are cold-blooded and are characterized by the presence of scales on their skin. Reptiles also lack an external ear and some reptiles such as snakes pick up vibrations through the ground.

3. Aves : The forelimbs of these organisms are modified into wings which help them in their flight. Most members of this group have a streamlined body which is specially designed to offer low air resistance during flight. Feathers play an important role in flight, thermal insulation and water-proofing. They are warm-blooded and are thus able to regulate their body temperature. Aves have beak which help them in preening and feeding.

4. Mammalia : These organisms are distinguished by the presence of mammary glands. They have two pairs of limb for walking, grasping, swimming etc. Skin is covered by hair and they have an external ear called pinnae. They are warm-blooded and viviparous in nature.

NCERT solutions for class 9 Science Chapter 7 Diversity In Living Organisms Intext Question

Q1 ) Why do we classify organisms?



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


Answer :

(i) Classification helps in exploring the diversity of life forms.

(ii) It simplifies to study them for scientific research.

(iii) It helps in studying the dependence and interactions between different organisms.

Q2 ) Give three examples of the range of variations that you see in life-forms around you.



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


Answer :


(i) Organisms of varying size which includes organisms from microbes to big mammals .

(ii) Organisms which differ in the pigmentation of various components in their body giving rise to transparent organisms and colour varying organisms from black crow to white swan.

(iii) Organisms which differ in their life span includes grass whose lifespan is around 7 to 10 years and redwood tree whose lifespan is around 500 to 700 years.

Q1 ) 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?



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


Answer :

A more basic characteristic for classifying organisms should depend upon the kind of cells they are made up of, which will differ prokaryotic and eukaryotic organisms.

An eukaryotic cell has membrane-bound organelles, including a well-defined nucleus, which allows cellular processes to be carried out efficiently in isolation from each other. These eukaryotic cells have the capacity to participate in the formation of a multicellular organism as the nucleated cells in eukaryotes can take up specialized functions thus performing complex metabolism.

A prokaryotic cell, which do not have a well defined nucleus and membrane bound organelles cannot perform complex metabolisms due to the absence of important organelles. As a result of which prokaryotic cells cannot contribute in the formation of multicellular organisms and is only present in organisms performing simple functions.

If the habitat or the place where an organism lives is taken as a basic characteristic for classification, then organisms cannot be differentiated on the basis of their structure and functions which can later make the study of each and every organisms difficult.

Q2 ) What is the primary characteristic on which the broad division of organisms is made?



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


Answer :

The primary characteristic on which the broad division of organisms is made is the nature of cell.

On the basis of nature of cell, organisms are broadly divided into two types :-

1. Prokaryotic organisms
2. Eukaryotic organisms


Prokaryotic organisms do not have a well defined nucleus and membrane bound organelles, and thus these organisms having prokaryotic cells cannot perform complex metabolisms.

Eukaryotic organisms have a well defined nucleus and membrane bound organelles, and thus these organisms having eukaryotic cells can perform complex metabolisms.

Q3 ) On what basis are plants and animals put into different categories?



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


Answer :

Plants and animals are put into different categories on the following basis :-

1) On the basis of presence or absence of cell wall.
2) On the basis of their mode of nutrition.
3) On the basis of their motility or locomotion.

Q1 ) Which organisms are called primitive and how are they different from the so-called advanced organisms?



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


Answer :

Primitive organisms are the groups of organisms which have a very simple and basic cell arrangement, mechanism and structure and they do not show any division of labour.

Advanced organisms are the organisms that possess millions of cells that are grouped into various tissues, organs and organ systems performing different complex functions such as in mammals.

Q2 ) Will advanced organisms be the same as complex organisms? Why?



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


Answer :

Yes, advanced organisms are the same as complex organisms.

Because advanced organisms means organisms that have undergone evolution which leads to their complexity of body organization.

The consequence of advancement leads to multiple cell arrangements that operate uniquely.

Q1 ) What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?



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


Answer :

The criterion for classification of organisms as belonging to Kingdom Monera or Protista is the presence or absence of well defined nucleus and membrane bound organelles which differentiates them as prokaryotic and eukaryotic organisms.

Kingdom Monera has prokaryotic organisms while Kingdom Protista has eukaryotic organisms.

Q2 ) In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic?



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


Answer :

The organism which is single-celled, eukaryotic and photosynthetic, will be placed in Kingdom Protista.

As the organism is single-celled, so it can't be placed in Fungi, Plantae or Animalia because these kingdoms consist of multicellular organisms.

The organism can't be placed in Monera because this kingdom consist of prokaryotes but the given organism is eukaryotic, so it can be placed in Kingdom Protista.

Q3 ) In the hierarchy of classification, which grouping will have the smallest number of organisms with maximum common characteristics and which will have the largest number of organisms?



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


Answer :

Monera has the smallest number of organisms with maximum common characteristics in the hierarchy of classification.
Monera was first proposed as a phylum by Ernst Haeckel in 1866. There are approximately 10,000 species of Monera on Earth.

Animalia has the largest number of organisms in the hierarchy of classification.
There are approximately 9 million species of Animalia on Earth.

Q1 ) Which division among plants has the simplest organisms?



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


Answer :

Thallophyta has the simplest organisms among the plants.

Its body is not differentiated into roots, stems and leaves as the body is thallus.

It includes unicellular organisms to large algae, fungi, lichens etc.

Q2 ) How are pteridophytes different from the phanerogams?



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


Answer :


Pteridophytes

Phanerogams

They do not produce seeds.

They produce seeds.

They have simple vascular system.

They have highly differentiated and advanced vascular system.

They have inconspicuous reproductive system.

They have well developed reproductive system.

Q3 ) How do gymnosperms and angiosperms differ from each other?



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


Answer :


Gymnosperm

Angiosperm

Companion cells of phloem are absent.

Companion cells of phloem are present.

Double fertilization is absent.

Double fertilization is present.

They have naked seeds.

They have covered seeds.

Q1 ) How do poriferan animals differ from coelenterate animals?



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


Answer :


Poriferan

Coelenterate

They exhibit cellular level of body organization.

They exhibit tissue level of body organization.

They are asymmetric and non-motile.

They are symmetric and motile.

They are acoelomate as they don't have coelom or body cavity.

They are coelomate as they have coelom or body cavity.

Q2 ) How do annelid animals differ from arthropods?



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


Answer :


Annelids

Arthropods

Their body shows metameric segmentation in which the body is segmented into identical intervals.

Their body lacks metameric segmentation and the body is segmented into head, thorax and abdomen.

They are hermaphrodite as they have both male and female sex organs.

They are not hermaphrodite as they have separate sexes.

They have closed circulatory system.

They have open circulatory system.

They do not have any skeleton.

They have an exoskeleton.

Appendages are absent.

Appendages are present.

Q3 ) What are the differences between amphibians and reptiles?



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


Answer :


Amphibia

Reptilia

They are adapted to live in both land as well as water.

They are adapted to live more on the land.

They can respire through gills and lungs.

They can respire through lungs.

They have skin which is moist and soft.

They have skin which is dry and scaly.

Larval stage takes place in water while the adulthood is spent on land.

Both the larval stage as well as adult stage takes place on land.

They have external fertilisation in which the fusion of the ovum and sperm takes place outside the female body.

They have internal fertilisation in which the fusion of the ovum and sperm takes place inside the female body and then they lay eggs which gets hatched outside the female body.

Q4 ) What are the differences between animals belonging to the Aves group and those in the mammalian group?



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


Answer :


Aves

Mammalia

They have their body covered with feathers which provides them thermal insulation and water proofing.

They have their body covered with hairs and the sweat glands are present under them.

They have a streamlined body which helps them in flight.

They don't have a streamlined body except for whales which helps them in swimming.

They possess a beak which helps them in preening and feeding but they lack teeth.

They don't have any beak but have a mouth with teeth which helps them in feeding.

They have pneumatic bones which are hollow and provides light body weight which is helpful during flight.

They have solid bones which becomes framework of their body.

Forelimbs are modified into wings which help them in flight.

Forelimbs are present as hands which help in various activities.



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