The Living Organisms and Their Surroundings

1.      Habitat : The place where organisms live most comfortably is called its habitat. It is the natural home of living things.

Aquatic habitat
(i)        When organisms live in water, it is known as aquatic habitat.
(ii)      Ponds, lakes, rivers, oceans, etc., are examples of aquatic habitat.
(iii)     Water is a medium in aquatic habitat.

Terrestrial habitat
(i)        When organisms live on land, it is known as terrestrial habitat.
(ii)      Forests, deserts, orchards, tea gardens and mountains are the examples of terrestrial habitat.
(iii)     Air is the medium in terrestrial habitat.

(i)        The mountain is a special terrestrial habitat where temperature is very low and the most of the areas are covered with snow.
(ii)      The plants like grasses, mosses and lichens and animals like snow bear, fox, water fowl, musk deer and wolf are found commonly in this habitat.

Several kinds of plants and animals may share the same habitat.

Adaptation : The presence of specific features and habits, which enable a plant or an animal to live in a particular habitat is called adaptation.

Components of a habitat

8.      Light

(i)        The sunlight is essential for the survival of the biotic components as the sun is the ultimate source of energy for all living things.
(ii)      The sunlight affects growth, flowering, seed germination and in many other ways to plants. Indoor plants put in the shade for a long time grow faster but become delicate and weak.
(iii)     Light also affects animals. Animals living in caves and burrows where sunlight cannot reach have very much reduced eyes e.g., Proteus. Amblyopsis do not have eyes.
(iv)     Nocturnal animals : Some animals like bats, cockroaches and owls are called nocturnal as they are active during night.


(i)        Temperature regulates growth, movement, reproduction, morphology and other aspects of life.
(ii)      Animals living in hot areas e.g., snakes, desert rats and lizards are not able to get sufficient water. They have thick skin and do not sweat.
(iii)     Desert animals e.g., camel have long legs. Long legs help them to lift their body above the ground. Thus, they are able to avoid direct contract with the hot ground.
(iv)     Animals having in very cold places. e.g., walrus, seals, penguins, yaks, polar bears etc. protect themselves from cold with their thick skin and thick fur.

10.   Water

(i)        All living organisms need water for their survival.

(ii)      Aquatic plants : These have the following adaptations :
·      Root system is poorly developed.
·      Air filled cavities found inside the body make them spongy and buoyant.
·      Leaves in submerged plants are thin and narrow while in floating plants they are big and flat with waxy coating.

(iii)     Desert plants : These have the following adaptations :
·      Well developed root systems.
·      Stem are succulent and spongy which help in storage of water. It is also green and performs photosynthesis.
·      Stomata (sunken) are less in number.
·      Leaves are either very small or converted into spines.

(iv)     Fishes : These have the following adaptations :
·      Tapering ends.
·      Slippery scales which help in swimming.
·      Gills for respiration.

(v)      Photoplanktons :These are floating plants in ocean and sea.

(vi)     Zooplankton :These are small animals living in ocean and sea.

Interaction of biotic and abiotic components : Organisms do not live in isolation but are interdependent.


Fig.  Interaction of biotic and abiotic components
12.   Living things : These are the objects which need water, air and nutrients for their survival.

Non-living things : These are the objects which do not need water, air and nutrients for their survival.

Cell : It is the basic structural and functional unit of the living things. The structure of a cell can be seen in the peel of an onion bulb or from the lower surface of a leaf under a magnifying glass or a microscope.

15.   Life : It is a process seen only in living objects in the form of growth, movement, feeding or eating, sensitivity, respiration, excretion and reproduction.

Characteristics of the living things : All living things on this earth possess certain basic characteristics. These include the following :
1.    Growth                             2. Movement                       3. Feeding
4.  Responsiveness               5. Excretion                        6. Respiration
7.  Cellular structure              8. Reproduction                  9. Adaptation.

Growth : It is defined as the permanent irreversible increase in the size and total weight of the living object.
       (i)  Animals grow for a certain period.
       (ii)  In case of trees growth takes place throughout the life.
(iii) Growth in plants and animals is influenced by several factor like food, climate, life style, etc.

Life span : Each animal lives for a certain period. This period is referred as life span.

Movement : Change in the position from one place to other is called movement.
(i)      Locomotion : The movement involving change of place in animals is called locomotion.
(ii)    Animals use wings (bird), fins (fish), limbs (cow, horse, buffalo, man) for locomotion.
(iii)   Plants generally show movements of various parts, e.g., Flower buds open, Roots grow away from light, when we touch the leaves of Mimosa (touch me not) they shrivel up.

Cellular Structure
(i)      Cells constitute plants and animal bodies.
(ii)    Cells are organized in various ways in different organisms.
(iii)   They help in carrying out various functions like nutrition, respiration, etc.
(iv)   They are called structural and functional unit of all organisms.

Nutrition : The process of taking food by organisms is generally referred as nutrition or nourishment.
(i)      Food and water are essential for life.
(ii)    Food provides energy that helps in the growth of body and its repair.
(iii)   Autotrophs : They are the living organisms which can synthesize their own food by photosynthesis, e.g., green plants.
(iv)   Heterotrophs : They are the living organisms which cannot manufacture their own food, e.g., all animals.
(v)    Saprophytes : The living organism which obtain their nutrition from the dead plants and animals are called saprophytes.
(vi)   Parasites : The plants and animals that feed on the other living bodies are called parasites.

(i)      Respiration is a process in which food taken by an organism combines with oxygen to release energy.
(ii)    Breathing : Taking in air and its release by animals is referred as breathing.
(iii)   We inhale oxygen (O2) and exhale carbon dioxide (CO2).


(i)      The removal of waste substances from the body of a living being is called excretion.
(ii)    The process of removal of wastes in plants is referred to as secretion.
(iii)   Latex, resin and gum are waste for the plant but useful for us.
24.   Response to Stimuli
(i)      Living beings respond to changes in their surroundings.
(ii)    Stimuli : The factors like food, water, light, touch, gravitational force etc. are stimuli (stimulus) to which plant and animals respond.
25.   Reproduction
(i)      Increase in progeny of a living being is called reproduction.
(ii)    Life produces life.
(iii)   Plants reproduce through seeds. Some plants also reproduce through vegetative parts.

Q.1. What is a habitat?

The place where animals live is known as habitat. A suitable habitat should be safe and food should be available in plenty. The climate of the habitat should be favourable for the animals living there.

Q.2. How are cactus adapted to survive in a desert?

The plants growing in deserts have adaptations to prevent water loss for example, cactus
(i)    has no leaves to prevent water loss through transpiration.
(ii)  stem is modified in such a way that it performs photosynthesis.
(iii)root system is well developed and grows in deep in search of water.

Q.3. Fill up the blanks :

a)    The presence of specific features, which enable a plant or an animal to live in a particular habitat, is called …………… .
b)    The habitats of the plants and animals that live on land are called ………….. habitat.
c)    The habitats of plants and animals that live in water are called ……………. Habitat.
d)    Soil, water and air are the ………… factors of a habitat.
e)    Change in our surroundings that make us respond to them, are called …………. .

(a) adaptation        (b) terrestrial        (c) aquatic    (d) abiotic      (e) stimuli.

Q.4. Which of the things in the following list are non-living?

        Plough, Mushroom, Sewing machine, Radio, Boat, Water hyacinth, Earthworm

In this list plough, sewing machine, radio and boat are non-living.

Q.5. Give an example of a non-living thing, which shows any two characteristics of living things.

One such example is cloud. It shows the following two properties of living things :
(i)     It grows in size.              (ii)   It shows movement.

Q.6. Which of the non-living things listed below, were once the part of a living thing?

          Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber

Butter, Leather, Wool, Cooking oil, Apple and Rubber are the non-living things from the list which were once the part of a living thing.

Q.7. List the common characteristics of the living things.

Some common characteristics of living things are listed below:
(i)      Growth                      (ii)   Movement                         (iii)   Feeding
  (iv)  Responsiveness       (v)   Excretion                           (vi)   Respiration
(vii)   Cellular structure      (viii) Reproduction                    (ix)   Adaptation

Q.8. Explain, why speed is important for survival in the grassland for animals that live there. (Hint : There are few trees or places for animals to hide in grasslands habitats.)

In Grassland habitats the places for animals to hide are limited and when an enemy attacks an animal it has to run fast so as to reach a safe place. If it fails, it has to loose its life. So, the speed in such places is very important in such habitats.

Q.1. Give the names of few habitats.

Pond, forest, sea shore, crop field, grass land, mountain, etc.

Q.2. Name some plants which live in dry areas.

Plants like cactus, munj, kaner, acacia (keekar), seesam etc. live in dry areas.

Q.3. Mention a few aquatic plants found in a pond.

Water, hyacinth, hydrilla, spirogyra, water lily, lotus, lemna, etc.

Q.4. Out of desert and aquatic plants whose roots are almost absent?

Aquatic plants.

Q.5. Which plants have leaves without pores?

Underwater plants.

Q.6. Plants in hilly areas have to bear high speed winds and cold. Which adaptation best helps them to face such conditions?

Tall, thin and straight trunk with needle shaped leaves.

Q.7. Snake is a ………….


Q.8. What is the main role of a producer?

To prepare food.

Q.9. Why head and snout of snake is tapering?

It is burrowing, digging adaptation.

Q.10. Name some plants which live in ponds.

Plants like lotus, hydrilla, hyacinth marselia, trapa, lemna, renum culus, typha, wolffia, nitella, selvinia live in ponds.

Q.11. Name the habitat of the following:

          (a) Cactus  (b) Hydrilla.

 Ans. (a) Cactus – Desert
          (b) Hydrilla – Aquatic

Q.12. Give one example of

          (a) Free floating plant     (b) Plants without root.

(a) Lotus
         (b) Ceratophyllum.

Q.13. Name the respiratory organ in

          (a) Terrestrial animals
          (b) Aquatic animals (fish)

(a) Lungs
         (b) Gills

Q.14. Visit a pond and make a list of animals found inside the water.

The animals like frogs, fishes, mollusks and certain insects are found inside the water. Protozoans like amoeba and turtles, water spiders, water skaters, dragon flies, king fishers, pond horons, ducks and many other types of animals are inhabiting the ponds.

Q.15. Why desert plants have long roots and spiny leaves?

Desert plants have long root and spiny leaves because :
(i)    Long roots go deep into the ground in search of water.
(ii)  Spiny leaves prevent the evaporation of water from the leaf surface.

Q.16. Give three main adaptive features in desert plant.

(i)   Well developed root systems.
         (ii)  Leaves either very small or converted to spines.
         (iii) Stem is green and fleshy in some plants.

Q.17. What is the ultimate source of energy for every ecosystem? Which biotic component can trap solar energy and how?

Sun is the ultimate source of energy. Green plants are capable to trap solar energy by plant in the process called photosynthesis using water and CO2 in the presence of sunlight.

Q.18. Mountain is special terrestrial habitat where temperature is very low and most of the areas are covered with snow. What is flora and fauna of this habitat at higher altitudes?

Ans. Flora :
Grasses, mosses and lichens.
         Fauna : Snow bear, fox, water fowl, musk deer, wolf.

Q.19. What are nocturnal animals? Give two examples of nocturnal animals.

Ans. Some animals are active during night time. These are called nocturnal animals. e.g., bats, cockroaches and owls.

Q.20. Why do camels have long legs?

Long legs of camels help them to lift their body above the ground. Thus, they are able to avoid direct contact with the hot ground.

Q.21. Why is excess of water not useful for plants?

When water is put in excess, air present in the soil is replaced by water. The plant roots will not get oxygen for respiration. So the amount of water in the soil should neither be too less, nor too much.

Q.22. If strong winds blow only in one direction, what will be the effect on trees?

Trees will bend in direction of wind and attain typical shape.

Q.23. Why do we feel more thirsty when it is hot?

When it is hot, sweat comes out of our body. Sweat is the result of the evaporation of water from our body. As our body loses water due to sweating, we feel thirsty and drink water.

Q.24. What adaptation of desert animals protect themselves from deficiency of water?

Animals living in hot places such as desert for example, snakes, desert rats and lizards are not able to get sufficient water. So these animals have thick skin, which prevents evaporation. Since they do not sweat, they cay survive without water for longer period.

Q.25. How do the animals living in cold places protect them from cold conditions?

The skin of animals like walrus, seals and penguins are thick and protect them from cold. Another way of protection, from cold is by having thick fur.

Q.26. How fish are adapted to live in water?

Fishes have following adaptations to live in water :
1)    In all the fishes, the head and tail portions are smaller than the middle portion, that is, the body tapers at both the ends. This shape of the body provides least resistance to the fishes when they swim in water.
2)    Skin of fishes are covered with scales. These scales are slippery, the slippery scales help the fish in swimming.
3)    We have lungs, which is an organ for respiration. Similarly, fishes have gills for respiration. They utilize oxygen dissolved in water and release carbon dioxide into the water.

Q.27. What is the adaptation mechanism of chameleon?

It changes colours to suit with its surroundings.

Q.28. What is reproduction?

It is a process by which living organism gives birth to the next generation of its own kind.

Q.29. What are the different types of reproduction?

(i) Asexual reproduction.
         (ii) Sexual reproduction.

Q.30. What do you mean by vegetative propagation in plants?

It is a process of growing plants from any vegetative part of plant like leaf, stem, root etc.

Q.31. What do you understand by life cycle and life span of a living thing?

Ans. Life cycle :
Life cycle is the series of changes in the life of an organism including reproduction, all the living things have a life cycle. The single cell or unicellular organisms, change into multicellular organism. The multicellular organisms also start their life from a single cell.
Life span : All the living things start their life. These living things grow into adults, remain alive for a certain time and finally die. The time period for which living things remain alive is called its life span. All the living things have a definite life span.

Q.32. “All living things respond to external stimuli”. Explain.

All living things respond to change in their surroundings. These changes which they respond to, are called stimuli. The living things show response to stimuli such as heat, light, touch, sound, smell and taste etc. The response of living things is usually in the form of some movement of their body part. Plant also perform movement, though at a slow rate. For example, chhui-mui, kachhan flowers of lotus and water lily show such type of activity. So all things (animals and plants) respond to external stimuli.

Q.33. What are the main characteristics of the living objects?

(i) Living objects need water, air and food for their survival.
        (ii) They show feeding, movement, respiration, excretion, growth, sensitiveness and reproduction.
(iii)They have a definite life span.
(iv)All living things are made up of cells.

Q.34. Indicate which of the following are living and which are non-living :

          buffalo, grass, grasshopper, table, aeroplane, pencil, bicycle, crow, banyan tree.

Living things                               Non-living things
         Buffalo                                           Table
         Grass                                             Aeroplane
          Grasshopper                                 Pencil
          Crow                                             Bicycle
          Banyan tree.

Q.35. What is life?

It is easy to say that this object is living and this is non-living, but it is difficult to say what is life. Life is the sum total of all the activities shown by a living object and the activities taking place inside its body.
Thus life is the process seen only in living objects in the form of growth, movement, feeding or eating, sensitivity, respiration, excretion and reproduction.

Q.36. Why bacteria and viruses are considered as ‘Immortal’?

Bacteria and viruses neither grow old nor die. Their growth remains continue for ever. They may survive a million years or even more if frozen or buried under salt. If they are buried in non-living environment, they stop growing but not die. Whenever they get favourable conditions, they start growing again. Hence they are considered as ‘immortal’.

Q.37. How will you prove that carbon dioxide is given out during respiration?

Take a test tube containing lime water. Bring it  near your mouth and breathe out into the test tube. By doing this lime water turns milky. This proves that carbon dioxide is given out during respiration as CO2 turns lime water milky.

Q.38. List the important characteristics of living things, which differentiate them from non-living things.


Living ThingsNon-living Things
1.    Living things need food, air and water.
2.    Living things grow.
3.    Living things can move on their own.
4.    Living things are sensitive. They respond to change around them.
5.    Living things reproduce themselves.
6.    Living things respire. They release energy from food.
7.    Living things excrete. They get rid of waste materials from their body.
8.    Living things have a definite life-span.
9.    Living things are made up of living cells.
1.    Non-living things do not need food, air or water.
2.    Non-living things do not grow.
3.    Non-living things cannot move on their own.
4.    Non-living things are not sensitive. They do not respond to change around them.
5.    Non-living things do not reproduce.
6.    Non-living things do not respire.
7.    Non-living things do not excrete.
8.    Non-living things exist for ever.
9.    Non-living things are made up of molecules.
Q.39. Name the type of locomotion in following animals :
          fish, earthworm, cow, birds, frog


Name of Animals
Type of Locomotion
1.    Fish
2.    Earthworm
3.    Cow
4.    Birds
5.    Frog
Q.40. Name the organs which are used by following animals for walking?
         Birds, Fish, Horse
Name of AnimalOrgan used for Locomotion
1.    Birds
2.    Fish
3.    Horse
Q.41. Give one words for the following sentences :

(i)        Any thing that have mass and occupies space.
(ii)      The process of taking food by organisms.
(iii)     The process of getting rid of wastes.
(iv)     The process of removal of wastes in plants.
(v)      The factors like food, water, light, temperature to which organisms respond.
(vi)     Production of new organisms of own kind.
(vii)    Increase in the size along with mass using energy.

(i) matter                 (ii) nutrition             (iii) excretion                (iv) secretion
        (v) stimuli                 (vi) reproduction     (vii) growth.


Q.1. Match the following items given in Column A with that in Column B.

Column AColumn B
(a)  Bird
(b)  Cat
(c)  Hydrilla
(d)  Whale
(e)  Cactus
(f)   Snow bear
(g)  Camel
(h)  Proteus
(i)    Amblyopsis
(j)    Cockroach
(i)   Nocturnal
(ii)  Have no eyes
(iii)Volant adaptation
(v)  Found on mountain
(vi)Aquatic plant
(vii)  Desert plant
(viii)Desert adaption
(ix)   Aquatic adaptation
(x)    Reduced eyes
Q.2. Fill in the blanks with appropriate words :

The place where organisms live is called ……….. .
(ii)          The plants and animals that live in water, it is called ……… habitat.
(iii)         Plants and animals that live on land, it is called ………… habitat.
(iv)         ……….. is a medium in aquatic habitat.
(v)          ……….. is a medium in terrestrial habitat.
(vi)         Soil, water and air are ………… components of a habitat.
(vii)       Plants put in shade for a longer time become ………. .
(viii)      Animals living in ………. have very much reduced eyes.
(ix)         Plants growing in hot and dry places are called ………… .
(x)          Desert plants have …………. Root system.
(xi)         Forests and trees act as ……….. .
(xii)       Animals depend on ……….. for their food.
(xiii)      Matter is anything that has ………… and occupies ………… .
(xiv)      The process of respiration involves ………… gases.
(xv)       Some objects are categorized as livings while others as ………… .

Q.3. State whether the statements given below are True or False :

Habitat is a special environment of an organism.
(ii)          Succulent is an adaptation in mesophytes.
(iii)         All birds do not have feathers.
(iv)         Fin is for aquatic life in fishes.
(v)          The plants and animals cannot survive without air.
(vi)         In all the fishes body tapers at both ends.
(vii)       Cactus plants have thick and fleshy stem to store water.
(viii)      Almost all types of plants occur in the sea.
(ix)         All living organisms need water for their survival.
(x)          Leaves in aquatic plants are reduced in size to minimize their evaporating surface.
(xi)         The flower of surajmukhi (sunflower) always faces the sun.
(xii)       Animals live in isolation and are independent.
(xiii)      Microorganisms are a part of abiotic components.
(xiv)      Habitat includes both living and non-living things.
(xv)       Mountain is a special terrestrial habitat where temperature is very low.
(xvi)      Large trees are abundant at higher altitudes.
(xvii)    Hilly trees do not have flowers.
(xviii)   All objects around us are made up of matter.
(xix)      All objects have similar shapes and size.
(xx)       Non-living objects do not carry out respiration.

Q.4. Choose the correct option in the following questions :

Which one of the following statements is correct?
(a)  Several kinds of plants and animals may share the same habitat.
(b)  All the animals and plants in a habitat are adopted to it.
(c)  Both the statements are correct.
(d)  None of these is correct.

Animals and plants have certain features which make them to survive in a particular habitat. This is called
(a)  adaptation                                (b) speciation
(c) specialization                              (d) evolution

Which is a biotic component of environment?
(a)  Plants                                           (b) Animals
(c) Microorganisms                          (d) All of these

Which is not an abiotic component of environment?
(a)  Soil                                               (b) Bacteria
(c) Water                                            (d) Air

Which is an example of an animal found in mountain region?
(a)  Leopard                                       (b) Yak
(c) Mountain goat                             (d) All of these

What is a characteristic of a desert plant?
(a)  No leaves or very small leaves (b) Spines
(c) Deep roots                                   (d) All of these

Respiration in aquatic animals occurs by
(a)  Lungs                                           (b) gills
(c) nostrils                                          (d) legs

Which is an aquatic adaptation?
(a)  Stream line body                        (b) Light and hollow bones
(c) Hair on body                                (d) gills

Bending of a stem towords sunlight is called
(a)  geotropism                                  (b) phototropism
(c) hydrotropism                               (d) nasticism

Sunken stomata are present in
(a)  hydrophytes                                (b) epiphyes
(c) xerophytes                                   (d) mesophytes


Q.1. Match the following items given in Column A with that in Column B.

Column AColumn B
(a)  Bird
(b)  Cat
(c)  Hydrilla
(d)  Whale
(e)  Cactus
(f)   Snow bear
(g)  Camel
(h)  Proteus
(i)    Amblyopsis
(j)    Cockroach
(iii) Volant adaptation
      (iv) Terrestrial
 (vi) Aquatic plant
 (ix) Aquatic adaptation
 (vii) Desert plant
(v)  Found on mountain
 (viii) Desert adaption
(xi)Reduced eyes
      (ii) Have no eyes
      (i)  Nocturnal

Q.2. Fill in the blanks :
        (i) habitat                       (ii) aquatic                              (iii) terrestrial
        (iv) water                       (v) air                                      (vi) abiotic
        (vii) delicate and weak   (viii) caves and burrows         (ix) xerophytes
        (x) long and extensive   (xi) wind-brakes                      (xii) plants
        (xiii) mass, space           (xiv) exchange                        (xv) non-living
Q.3. True/False :
         (i) True           (ii) False          (iii) False          (iv) True            (v) True
         (vi) True         (vii) True          (viii) True         (ix) True             (x) False
         (xi) True         (xii) False         (xiii) false         (xiv) True           (xv) True
         (xvi) False      (xvii) False       (xviii) True        (xix) False         (xx) True
Q.4. Choose the correct option :

  (i)      (c) Several kinds of plants and animals may share the same habitat and adopt it.
  (ii)     (a) Presence of features which enable plants and animals to live in a habitat are
           called adaptations.
  (iii)     (d) All these constitutes are biotic components.
  (iv)     (b) Bacteria are living beings.
  (v)     (d) Leopard, mountain goat and yak are found in mountain region.
  (vi)     (d) All these characters help the plants to survive in the scarcity of water.
  (vii)    (b) Aquatic animals uses gills for respiration.
  (viii)   (a) Streamline body helps them to swim.
  (ix)     (b) Bending of stem toward sunlight is called phototropism.
  (x)      (c) Sunken stomata found in xerophytes plant, such plant grow under poor water condition.