Important Questions for CBSE Class 9 Science Chapter 7 Diversity in Living Organisms

Important QuestionsNCERT SolutionsRD Sharma Solutions


Question. 1  Name one basic characteristic for classifying organisms.
Answer. Cell structure.

Question. 2  What was the modification introduced by Woese in kingdom Monera ? [SAII -2012]
Answer.  Carl Woese modified the Kingdom Monera by dividing it into Archae-bacteria and Eubacteria.

Question. 3  Define the term henpaphrodite. Give one example [SAII – 2014]
Answer.  A hermaphrodite is an organism that has both male and female genitalia.
Example: Earthworm.

Question. 4  What do you understand by diploblasty ? Give one example of an organism which is diploblastic.  [SAII -2014]
Answer.  Diploblasty is a condition of the blastula in which there are two primary germ layers — the  ectoderm and the endoderm.
Example: Jellyfish.

Question.5  A pore bearing organism like creature ‘A’ belongs to a phylum ‘B’ of kingdom Animalia. Identify ‘A’and’B’ [SAII- 2014]
Answer. A — Sponges, B — Porifera.

Question.6  Homo sapiens is the scientific name of human beings. What do these two terms imply ?  [SAII – 2014]
Answer.  Homo sapiens : Homo is the human”genus and sapiens is the only surviving species of the genus Homo.

Question.7  Rewrite the scientific names correctly (i) panthera tigris (ii) periplaneta Americana. [SAII – 2014]
Answer.  (i) Panthera tigris (ii) Periplaneta americana.

Question.8  Name two egg laying mammals.
Answer.  (i) Platypus (ii) Echidna.

Question.9  What is the primary characteristic on which the first division of organisms is made ?
Answer.  The primary characteristics on which the first division of organisms is made in : Do the cells
occur singly or are they grouped together and do they live as an indivisible group

Question.10  Which division among plants has the simplest organisms ?
Answer.  The division ‘Thallophyta’ among plants has the simplest organisms as they do not have well- differentiated body design.

Question.1  In which two categories, the organisms are divided on the basis of evolution ? How are the two categories different from each other ? [SAII – 2014]
Answer.  On the basis of evolution, the organisms are divided into two categories :
(a) ‘Primitive’ or ‘lower’ organisms
(b) ‘Advanced’ or ‘higher’ organisms
Advanced organisms results from the gradual development of more complex organisms jfrom the simpler ones /.e., primitive organisms.

Question.2 Why is it difficult to classify bacteria ? Give two reasons. [SAII -2014]
Answer.  It is difficult to classify bacteria because :
(i) These organisms do not have a well defined nucleus or organelles and do not have multicellular body designs.
(ii) Mode of nutrition of these organisms can be either autotrophic or heterotrophic.

Question.3 What are species ? State in terms of (1) hierarchy of classifications and (2) in relation to reproduction. [SAII -2014]

  1. Hierarchy of classification: Species is the lowermost category in the hierarchy of classification of groups of organisms.
  2. In relation to reproduction : A species includes all organisms that are similar enough to breed and perpetuate.

Question.4 What are Cryptogams ? Why are they called so ?
Answer.  Thallophytes, Bryophytes and Pteridophytes are classified as Cryptogams as they have hidden reproductive organs.

Question.5 We start classification of plants on the basis of differentiation of plant body.
(i) Which division lacks a well differentiated body design ?
(ii). Where are such plants pr&iominantly found ? [SAII -2014]
(i) Thalldphyta
(ii)These plants are predominantly found in aquatic habitat.

Question.6 Differentiate between Bryophyta and Pteridophyta. Give one example of each.

Question.7 Prawn, housefly and spider belong to one group.
(i) Name the group.
(ii)Justify the name given to this group.
(i) Arthropoda.
(ii) They have jointed legs. The word ‘arthropod’ means jointed legs.

Question.8 What is meant by warm-blooded and cold-blooded animals ? Explain. [SAII – 2014]
Answer.  Warm-blooded animals have a relatively higher blood temperature and can maintain the constant  internal body temperature through metabolic processes. Mammals and birds are warm-blooded  animals.
Cold-blooded animals like reptiles, amphibians and fish continuously change their body temperature
with change in the temperature of the environment.

Question.9 List two distinguishing features between annelids and arthropods.

  1. Arthropods have jointed legs that annelids lacks.
  2. Arthropods have their coelomic cavity filled with blood that is absent in annelids,

Question. 10 Write the type of body cavity and symmetry possessed by nematodes. [SAII-2014]
Answer.  Body cavity: Pseudocoelom.
Symmetry: Bilateral.

Question.11 Give two features of Pisces.

  1. Their skin are covered with scales/plates.
  2. They are cold-blooded animals.

Question.12 On what basis are plants and animals put into different categories ?
Answer.  Plants and animals are put into different categories on the basis of their ability to make their f own food.  Being able to produce one’s own food versus having to get food from outside would make very different body designs necessary.

Question.13 Will advanced organisms be the same as complex organisms ? Why ?
Answer.  Yes, advanced organisms be the same as complex organisms because there is a possibility that complexity in design will increase over evolutionary time. Thus, it may not be wrong to say that ‘older’ (‘primitive’ or ‘lower’) organisms are simpler while ‘younger’ (‘advanced’ or ‘higher’) organisms are more complex.

Question.14 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? [SAII – 2011]
Answer.  The grouping having the smallest number of organisms with a maximum of characteristics in ; common is the ‘species’. While the grouping having the largest number of organisms with a maximum of characteristics in common is the ‘kingdom’.

Question.15 Explain the basis for grouping organisms into five kingdoms.[SAII – 2011]
Answer.  The basis for grouping organisms into five kingdoms depends on their:
(a) Cell structure.
(b) Mode and source of nutrition.
(c) Body organisation.

Question.1  Classify the following organisms into their respective kingdoms as per Whittaker’s five kingdom classification:
Amoeba, Euglena, Birds, Herbs, Cats, Lactobacillus.
Answer.  Amoeba — Protista Euglena — Protista
Birds — Animalia Herbs — Plantae
Cats — Animalia Lactobacillus — Monera

Question.2  Make a table to differentiate between Monera and Fungi on the following basis:
(а) Prokaryotic/Eukaryotic
(b) Cell wall

Question. 3  Study the figure and Answer the following questions:

Question.4  Give three differences between Monocot and Dicot plant. [SAII – 2014]

Question.5  What is meant by characteristic of an organism ? Mention two characteristics of class reptilia.  [SAII- 2014]
Characteristics of an organism are the features that help us in knowing, identifying and classifying the organism.
The two characteristics of class Reptilia are as follows :

  1. These are cold-blooded animals.
  2. They respire through lungs.

Question.6  State any two characteristics of mammalia. Name two egg laying mammals. [SAII – 2014]
Answer.  Characteristics of mammalia :

  1. Mammals are warm-blooded animals having hairs on body.
  2. They have four chambered heart.
  3. They have mammary glands for the production of milk to nourish their young onesv
  4. Skin has sweat or oil glands.
    Egg laying mammals: Platypus, Echidna.

Question.7  Explain the following terms:
(i) Bilateral symmetry, (ii) Triploblastic animals and (iii) Open circulatory system.[SAII-2014]
(i) Bilateral symmetry : It means that the left and right halves of the body have the same design. It is fourid in Platyhelminthes.
(ii) Triploblastic animals : In triploblastic animals, there are three layers of cells from which differentiated tissues can be made.
(iii) Open circulatory system : In open circulatory system, blood does not flow in well defined blood vessels. Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood.

Question.8  Tabulate the following features and compare Reptilia, Aves and Mammalia:
(a) Exoskeleton (b) Number of chambers in heart [SAII – 2014]

Question.9  Write appropriate terms for the following:
(a) Animals that are able to maintain a certain body temperature over a wide range of temperature in the environment.
(b) Plants which bear naked seed.
(c) Animals which have pseudocoelom.
Answer.  (a) Warm-blooded animal, (b) Gym nosperms, (c) Nematoda.

Question.10  Give three examples of the range of variations that you see in life forms around you.
Answer.  The following range of variations can be seen in different life forms which occurs on Earth.

  1. Variation in size: Some microscopic bacteria are few micrometre in size whereas blue whale
    and redwood trees of California are approximately of 30 metres and 100 metres respectively.
  2. Variation in lifespan : Some pine trees live for thousands of years while insects like mosquitoes die within a few days.
  3. Variation in body colours: Some life forms such as worms are colourless or even transparent whereas many of the birds, insects, flowers etc., are brightly coloured.

Question.11  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 with?
Answer.  The more basic characteristic for classifying organisms is the kind of cells they are made of because:
(a) An eukaryotic cell has membrane-bound organelles, including a nucleus, which allow cellular processes to be carried out efficiently in isolation from each other.
(b) Further, nucleated cells would have the capacity to participate in makinga multicellular organism because they can take up specialised functions. Therefore, this is a basic characteristic of classification.

Question.12  Which organisms are called primitive and how are they different from the so-called advanced organisms ? [SAII – 2011]

Question.13  How are pteridophytes different from the phanerogams? [SAII-2011]

Question.14 How do gymnosperms and angiosperms differ from each other ? [SAII -2011]

Question.15  How would you choose between two characteristics to be used for developing a hierarchy in classification ?
Answer.  The characteristics which are taken into account for developing a hierarchy in classification are :

  1. Whether cell has membrane-bound organelles present or not. Because such cells would have different biochemical pathways having an effect on every aspect of cell design.
  2. Whether the cells occur singly or are they grouped together. Because this makes a very basic distinction in the body designs of organisms.
  3. Whether organisms produce their own food (plants) or acquire it(animals).

In this way, we can build-up a whole hierarchy of mutually related characteristics to be used for classification.

Question.16  How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals ?
Answer.  The characteristics of body design used for classification of plants will be very different from those important for classifying animals. This is because the basic designs are different, based on the need to make their  own food (plants) or acquire it (animals). Therefore, these design features (having a skeleton) are to be used to make subgroups, rather than making broad groups.

Question.1 X, Y and Z are living organisms.
(a) Identify the group to which they belong on the basis of following features. .
(i) X — Microscopic, unicellular, prokaryotic.
(ii) Y — Microscopic, unicellular, eukaryotic, and shows locomotion with the help of pseudopodia/flagella.
(iii) Z — Multicellular, filamentous, eukaryotic, autotrophic and aquatic.
(b) Which amongst the above is most advanced ?
(c) Name one organism each belonging to the groups of X, Y and Z.  [SAII-2014]
(a) (i) Monera, (ii) Protista, (iii) Plantae (Thallophyta)
(b) Fungi are most advanced organisms as compared to Protista and Monera.
(c) X — Bacteria
Y — Amoeba
Z —Spirogyra.

Question.2 Give the appropriate term for each of the following:
(а) Complex sugar that makes the fungal cell wall.
(b) Plants which bear naked seeds.
(c) Blue-green algae.
(d) Basic unit of classification.
(e) Group of unicellular eukaryotic organism. [SAII – 2014]
(a) Chitin
(b) Gymnosperms
(c) Cyanobacteria
(d) Cell structure
(e) Protista.

Question.3 (a) Why are angiosperms so called ? In which structures do the seeds develop ? Why are cotyledons considered an important part of seed ?
(b) Differentiate between the two categories of angiosperms giving an example of each.  [SAII – 2014]
(a) Angiosperms are so called because these plants have covered seeds.
Seeds develop within ovary which later modify into fruit.
Cotyledons are considered an important part of seed as these are seed leaves. In many instances, they emerge and become green when the seed germinates.
(b) The angiosperms are divided into two categories depending upon the number of cotyledons present in the seeds:
(i) Monocot — Plants having single cotyledon, e.g., Paphiopedilum, maize.
(ii) Dicot — Plants having two cotyledons, e.g., Ipomoea, sunflower.

(a) Identify the organism shown in the picture and write the common name and scientific name of the organism.
(b) Name its phylum and kingdom.
(c) Which organ of digestive system normally harbours this organism ?
(a) It is Ascaris.Common name is Roundworm.Scientific name is Ascaris lumbricoides.
(b) Phylum — Nematoda and Kingdom-Animalia.
(c) Small intestine (an organ of digestive system) normally harbours this organism.

(a) Identify three features possessed by all chordates.
(b) Name the classes of vertebrates which have the following characteristics:
(1) Animals that have streamlined body and gills for breathing.
(2) Animals that are found both on land and in water.
(3) Animals that have mammary glands for the production of milk to nourish their young ones.
(a) Features of chordates:

  • They have notochord.
  • They have a dorsal hollow nerve chord.
  • They are triploblastic.
  • They have paired gill pouches.
  • They are coelomate.


  1. Pisces
  2. Amphibians
  3. Mammals.

Question.6 What is the criterion for classification of organisms as belonging to kingdom Monera or Protista? [SAII – 2011]
Answer.Criterion for classification of organisms belonging to kingdom Monera:
(i) These organisms do not have a defined nucleus or organelles, nor do any of them show multicellular body designs.
(ii) Some of them have cell walls while some do not have.
The mode of nutrition of organisms in this group can be either by synthesizing their own food (autotrophic) or getting it from the environment (heterotrophic).
(iv) This group includes bacteria, blue-green algae or cyanobacteria and mycoplasma.
Criterion for classification of organisms belonging to kingdom Protista:
(i) This group includes many kinds of unicellular eukaryotic organisms.
(ii) Some of these organisms use appendages, such as hair-like cilia or whip-like flagella for moving around.
(iii) Their mode of nutrition can be autotrophic or heterotrophic.
(iv) This group includes unicellular algae, diatoms and protozoans.

Question.7 How do poriferan animals differ from coelenterate animals ? [SAII -2011]

Question.8 How do annelid animals differ from arthropods ? [SAII -2014]

Question.9 What are the differences between amphibians and reptiles ? [SAII – 2011]

Question.10 What are the differences between animals belonging to the Aves group and those in the Mammalia
group ? [SAII- 2011]

Question.11 What are the advantages of classifying organisms ?
Answer.  The importance of classification is :

  1.  It provides us an information regarding the diversity of plants and animals.
  2.  It provides insight into the origin of organism and interrelationship between them.
  3. It makes the study of wide variety of organisms.
  4.  It helps in understanding the evolution of organisms. –
  5. Various fields of applied biology like agriculture, environmental biology etc., also depends t upon correct identification and classification of pest, disease, vector etc.
  6. It serves as a base for the development of other biological sciences like biogeography and

The science of classification thus contributes to a larger extent in advancing knowledge in
most of the other disciplines of biology.

Question.12 What are the major divisions in the plantae ? What is the basis for these divisions ?  [SAII – 2014]
The major divisions in the kingdom plantae are :
(i) Thallophyta (ii) Bryophyta
(iii) Pteridophyta (iv) Gymnosperms
(v) Angiosperms.
The basis of these divisions are :
(a) Whether the plant body has well differentiated, distinct components.
(b) Whether the differentiated plant body has special tissues for the transport of water and other substances within it.
(c) The ability to bear seeds.
(d) Whether the seeds are enclosed within fruits.

Question.13 Explain how animalflTrvertebrata are classified into further subgroups.
Answer.  The following characteristics are considered while classifying Vertebrata into further subgroups – (classes) :


Question.1 Distinguish between the following:
(a) Fungi and Plantae on the basis of nutrition.
(b) Gymnosperms and Angiosperms on the basis of fruits. [SAII-2014]
Answer.  (a) Fungi shows heterotrophic mode of nutrition /.e., they cannot prepare their food while Plantae  are autotrophs i.e., they prepare their own food by the process of photosynthesis.
(b) Gymnosperms bear naked seeds while Angiosperms have seeds which develop inside an organ which later modifies into a fruit.

Question.2 A plant specimen was found without differentiated roots. ‘
(a) Which plant structure helps in attaching this plant to the substratum ?
(b) To which group you will keep this plant ?
(c) Which plant could it be ?
Answer.  (a) Thallus, (b) Thallophyta, (c) Algae.

Question.3 Give a comparative account of the following:
(a) Ulothrix and Funaria
(b) Marchantia and Marselia
(c) Fern and Pinus
(d) Cycas and rose
(e) Wheat and gram
(a) Ulothrix is Thallophytes and Funaria is Bryophytes.
(b) Marchantia is Bryophytes and Marsilea is Pteridophytes.
(c) Fern and Pinus both the plants belongs to group Pteridophyta.
(d) Cycas is gymnospermic plant whereas rose is angiospermic plant.
(e) Wheat is monocot plant whereas gram is dicot plant.

Question.4 Protochordates possesses a notochord in larval forms. Appraise the use of this feature in these animals. :
Answer.  The notochord is a long rod-like support structure (chord = string) that runs along the back of the animal separating the nervous tissue from the gut. It provides a place for muscles to attach for ease of movement.

Question.5 Write two examples of each of the following:
(a) Animals that do not loeomote.
(b) Flightless birds.
(c) Molluscs without shell.
(a) Shrimps and squids.
(b) Kiwi and ostrich.
(c) Octopus and squids.

Question.6 Associate the following features with groups in which they first appeared. ..
(a) Vascular tissues
(b) Notochord
(c) Seeds inside fruits.
(a) Vascular tissues —Pteridophyta
(b) Notochord — Protochordata
(c) Seeds inside fruits — Angiosperms

Question.7 Give the scientific and common name of an organism that possesses the following:
(а) Organisms that are found both on land and water.
(b) Organisms that lay eggs on land.
(c) Organisms having skeleton made of cartilage.
(d) Organisms having hair on their body.
(e) Organisms that are cold-blooded.
(a) Frog (Ranatigrina)         (b) Platypus (Ornithorhynchus anatinus)
(c) Shark (Selachimorpha) (d) Human beings (Homo sapiens)
(e) Rohu (Labio rohita).

Question.8 Match items of column (A) with items of column (B)
(A)                                                                          (B)
(a) Pore bearing animals                               (A) Arthropoda
(b) Diploblastic                                                  (B) Coelenterata
(c) Metameric segmentation                        (C) Porifera
(d) Jointed legs                                                  (D) Echinodermata
(e) Soft bodied animals                                   (E) Mollusca
(f) Spiny skinned animals                              (F) Annelida
(a) C (b) B (c) F (d) A (e) E

Question.9 Match items of column (A) with items of column (B).
(A)                                                                     (B)
(а) Naked seed                                              (A) Angiosperms
(b) Covered seed                                          (B) Gymnosperms
(c) Flagella                                                     (C) Bryophytes
(d) Marchantia                                             (D) Euglena
(e) Marsilea                                                   (E) Thallophyta
(f) Cladophora                                              (F) Pteridophyta
(g) Pencillium                                              (G) Fungi
(a) B (b) A (c) D (d) C (e) F (f) E (g) G

Question.10 Classify the following organisms based on the absence/ presence of true coelom (i.e., acoelomate, pseudocoelomate and coelomate)
Spongilla, Sea anemone, Planaria, Liver fluke, Wuchereria, Ascaris, Nereis, Earthworm, Scorpion, Birds, Fishes, Horse.
Spongilla – Acoelomate Sea anemone – Acoelomate Planaria – Acoelomate
Liver fluke – Acoelomate
Wuchereria – Pseudocoelomate
Ascaris – Pseudocoelomate
Nereis – Coelomate
Scorpion – Coelomate
Earthworm – Coelomate
Birds,’ fishes and horse – Coelomate

Question.11 Endoskeleton of fishes are made-up of cartilage and bone; classify the following fishes as
cartilaginous or bony:
Torpedo, Sting ray, Dogfish, Rohu, Anglerfish, Exocoetus.
Answer.  Torpedo-Cartilaginous,Stingray-Cartilaginous, Dogfish-Cartilaginous, Rohu-Bony, Anglerfish- Cartilaginous, Exocoetus-bony.

Question.12 Classify the following based on number of chambers in their heart.Rohu, Scoliodon, Frog, Salamander, Flying lizard, King Cobra, Crocodile, Ostrich, Pigeon, Bat, Whale.
Answer.  Rohu, Scoliodon 2 chambered.
Frog, Salamander, Flying lizard, King Cobra-3 chambered.
Crocodile, Ostrich, Pigeon, Bat, Whale-4 chambered.

Question.13 Give examples for the following:
(a) Bilateral, dorsiventral Symmetry is found in………………………….
(b) Worms causing disease elephantiasis is………………………….
(c) Open circulatory system is found in ………………………….where coelomic cavity is filled with blood
(d)………………………….are known to have pseudocoelom.
(a) Liver fluke (b) Filarial worm
(c) Arthropods (d) Nematodes

Question.14 Label a, b, c and d in given fig. Give the function of (b).
(a) Dorsal fin (b) Caudal fin
(c) Pelvic fin (d) Pectoral fin
Function of CaudaHm(b)-Caudal fin helps in streamlined movement in water.

Question.15 Classify Rohu, Scoliodon, Flying lizard, King Kobra, Frog, Salamander, Ostrich, Pigeon, Bat, – Crocodile and Whale into the cold-blooded/warm blooded animals.
Cold-blooded-Rohu, Scoliodon, Frog, Salamander, Flying Lizard, King Cobra, Crocodile.
Warm-blooded-Ostrich, Pigeon, Bat, Whale. v

Question.16 Why do we keep both snake and turtle in the same class ?
Because both are:
(1) cold-blooded
(2) have scales
(3) breathe through lungs
(4) have three chambered fjeart and
(5) they lay eggs with tough covering.

Higher Order Thinking Skills (HOTS) Question.

Question. 1 List any two similarities and two differences between Amoeba and Paramecium.
Answer.  Similarity between Amoeba and Paramecium
(a) Both are unicellular and eukaryotic organisms.
(b) Both the organisms have food vacuole.
Difference between Amoeba and Paramecium
(a) Locomotary organ of Amoeba is pseudopodia where Paramecium moves with the help of . cilia.
(b) Amoeba has only one nucleus whereas Paramecium have two nuclei.

Question.2 You are provided with the seeds of gram, wheat, rice, pumpkin, maize and pea. Classify them whether they are monocot or dicot.
Gram-dicot Wheat-monocot
Rice-monocot Pumpkin-dicot
Maize-monocot Pea-dicOt

Question.3  Define the terms and give one example of each:
(a) Bilateral symmetry (b) Coelom (c) Triploblastic
(a) The left and right halves of the body have the same design, e.g. Liver fluke.
(b) Coelom is the internal body cavity between visceral organs and body wall in which well developed organs can be accommodated, e.g., butterfly.
(c) Animals having three layers of cells from which differentiated tissue can be made are called triploblastic, e.g., starfish.

Question.4  You are given Leech, Nereis, Scolopendra, Prawn and Scorpion; and all have segmented body organisation. Will you classify them in one group ? If no, give the important characters based on which you will separate these organisms into different groups. ‘
Answer.  All organisms given in the question do not belong to same group. Leech and Nereis belong to phylum annelida because they have metamerically segmented body, i.e., body is divided into many segments internally by septa. Body segments are lined up one after the other from head to tail. But Scolopendra, prawn and scorpion belong to phylum arthropoda as these have jointed legs and open circulating system.

Question.5  Which organism is more complex and evolved among Bacteria, Mushroom and Mango tree ? Give reasons.
Answer.  Mango tree is more complex and evolved because, it is eukaryotic, autotrophic, terrestrial sporophyte with covered seed. The bacteria is unicellular prokaryote and fungi are the heterotrophic, simple thallophyte with no tissue systems –

Question.6  Differentiate between flying lizard and bird. Draw their diagram.
Flying lizard belongs to group reptiles and characterised as cold-blooded, body covered with scales and having three chambered heart, while Birds belong to group aves and have characteristics of being warm-blooded, having feather covered body, fore limbs modified as wings and having four chambered heart.

Reasoning Questions

Question.1  State reasons for each of the following:
(i) Echidna and Platypus lay eggs but are considered as mammals.
(ii) Forelimbs of birds are modified.
(iii) Crocodiles have four-chambered heart but are still reptiles.
(i) Echidna and Platypus lay eggs but are considered as mammals because they both are semi- aquatic as they can stay both in water as well as out of it.
(ii) Forelimbs of birds are modified into wings to fly.
(iii) Crocodiles have four-chambered heart but are still reptiles as they lay eggs with tough coverings and do not need to lay their eggs in water, unlike amphibians.

Question.2  State reason for the following:
(a) Tapeworm does not have digestive trait.
(b) Frogs use both skin and lungs for breathing.
(c) Birds have pneumatic/hollow bones.
(a) Tapeworm does not have digestive trait as tapeworm are parasites and their body wall absorbs the digested food from the host animal iri which they live.
(b) Frogs use both skin and lungs for breathing as skin is effective for breathing when they are in water whereas lungs are used when the frog is on land or swimming at the surface. ”
(c) Birds have pneumatic/hollow bones to lighten their weight and make it easier for them to fly.

Question.3  Why do we keep both snake and turtle in the same class ?
This is because both snake and turtle:
(i) are cold-blooded
(ii) have scales
(iii) breathe through lungs, and
(iv) do not need to lay their eggs in water.

Question.4  Give reasons:
(a) Animals of phylum platyhelminthes are called flatworms.
(b) Bryophytes are called amphibians of the plant kingdom.
(c) Fungi are called saprophytes.
(d) Bacteria and tapeworms are very different in their body design.
(e) Plants like Pinus and Deodar are called gymnosperms.
(a) Animals of phylum platyhelminthes are called flatworms because the body is flattened dorsiventrally, from top to bottom.
(b) Bryophytes are called amphibians of the plant kingdom as they are found on both land as
well as in water.
(c) Fungi are called saprophytes as they use the decaying organic material as food.
(d) Bacteria and tapeworms are very different in their body design due to change in course of
(e) Plants like Pinus and Deodar are called gymnosperms as the plants of this group bear naked seeds and are usually perennial, evergreen and woody.

Question.5  Give reasons for the following:
(i) From phylum platyhelminthes onwards, animals are categorised as ‘triploblastic.
(ii) The presence of ‘coelom’ in an animal’s body is considered as advantageous. [SAII-20 74]
(i) There are three layers of cells from which differentiated tissues can be made. This allows outside and inside body linings as well as some organs to be made. There is thus some degree of tissue fqrmation.
(ii) Coelom is a true internal body cavity in which well-developed organs can be accommodated.

Important Topics/Areas/Questions which are
frequently asked in the examination

Question.1  Which organisms are called primitive ? How are they different from the advanced organisms ?  [SAII-2014]
Primitive organisms: Organisms which have simpler ancient body designs that have not changed much over evolutionary time are called primitive organisms.
Advanced organisms : Organisms which have complex body designs that have changed over evolutionary time are called advanced organisms.

Question.2  Identify the group comprising specialised tissue for the conduction of water in the plant body. Name one such plant. [SAII-2014]
Answer.  The group pteridophyta shows specialised tissue for the conduction of water in the plant body. Marsilea is one such plant that belongs to this group.

Question.3  Name the type of flowers that can be seen in a: (i) Monocot plant, (ii) Dicot plant.
(i) Monocot plant: Trimerous flower having one cotyledon in the seed.
(ii)Dicot plant: Pentamerqips flower having two cotyledons in the seed.

Question.4  State which were the first terrestrial plants ? Mention two characteristic features of these plants.
(a) Bryophyta are the first terrestrial plants. These are called the “amphibians of the plant kingdom.
(b) The two characteristics features of these plants are :
(i) The plant body is commonly differentiated into stem and leaf like structures.
(ii) There is no specialised tissue for the conduction of water and other substances from one part of the plant body to another.

Question.5  Differentiate between maize plant and mustard plant in terms of:
(a) root system, (b) leaf venation, (c) number of cotyledons

Question.6  What are Phanerogams ? Name its two groups along with the criteria of division. [SAII-2013]
The plants with well differentiated reproductive tissues that ultimately makes seeds are called as phanerogams. Seeds are the result of the reproductive process. They consist of the embryo along with the stored food, which serves for the initial growth of the embryo during germination.
The phanerogams are further divided into two groups, based on whether the seeds are naked or enclosed within fruits – gymnosperms and angiosperms.

Question.7  Name the phylum to which the following organisms belong.
(a) Earthworm (6) Planaria (c) Sycon
(d) Starfish (e) Housefly (f) Octopus
(a) Earthworm-Annelida
(b) Planaria – Platyhelminthes
(c) Sycon – Porifera
(d) Starfish – Echinodermata
(e) Housefly – Arthropoda
(f) Octopus – Mollusca

Question.8  Write three characteristics each of the following groups of animals: [SAll-2012, 2014]
(a) Platyhelminthes (b) Nematoda
(a) Platyhelminthes:
(i) The body is bilaterally symmetrical.
(ii) They are triploblastic.
(iii) Body is flattened dorsiventrally.
(b) Nematoda:
(i) Body is bilaterally symmetrical.
(ii)They are triploblastic.
(iii)Body is cylindrical.

Question.9  Name the following:
(a) An egg laying mammal.
(b) A reptile with four chambered heart.
(c) Scientist who proposed the five kingdom classification.
(d) A mammal which can fly.
(e) An aquatic mammal.
(f) Group of animals having fins for locomotion.
(a) Platypus, (b) Crocodile, (c) Robert Whittaker, (d) Bat, (e) Whale, (f) Pisces.

Question.10  Out of the various phyla under animal kingdom, choose the one that fits the given description. Also give an example in each case:
(a) Have dorsiventrally flattened body.
(b) Water driven tube system is present for locomotion.
(c) Mostly with shells, some are without shell.
(d) Holes are present all over the body.
(e) Longest phylum due to a variety of adaptation. [SAII-2013, 2014]
(a) Platyhelminthes (Planaria),
(b) Echinodermata (Starfish),
(c) Mollusca (Pila)
(d) Porifera (Sycon),
(e) Arthropoda (Spiders).

(a) What do you understand by nomenclature ?
(b) Who introduced this system ?
(c) Give any four conventions while writing scientific names.
(a) Nomenclature is the system of scientific naming of living beings so that they can be uniformly identified all over the world.
(b) The system of scientific naming was introduced by Carolus Linnaeus.
(c) Conventions:
(i) The name of genus begins with a capital letter.
(ii) The name of species begins with a small letter.
(iii) When printed, the scientific name is typed in italics.
(iv) When written by hand, the genus name and species names have to be underlined