Topic outline

    • The Living Organisms and Their surroundings

      Q58. State the characteristics of living things.

      Ans. Characteristics of living things are:

                                i.        Living things need food.

                               ii.        Living things show growth.

                              iii.        Living things respire.

                              iv.        Living things respond to stimuli.

                               v.        Living organisms excrete.

                              vi.        Living things reproduce.

                vii.        Living things move.


      Q59. How does body of a person adjust who lives in plains and suddenly go to high mountains regions?

      Ans. A person who live in the plains and suddenly go to high mountain regions may experience difficulty in breathing and doing physical exercise for some days. After some days, his body adjusts to the changed conditions on the high mountain. Such small changes that take place in the body of a single organism over short periods, to overcome small problems due to changes in the surroundings, are called acclimatisation.

      Q60. What are Hydrophytes? Write its adaptations.

      Ans. Hydrophytes are the plants that grow in watery places or the places which remain wet throughout the year. Example: hydrilla, lotus etc.

      Hydrophytic Adaptations are:

                                   i.        Root system is not well developed.

                                 ii.        Root hairs and root cap are absent.

                               iii.        Leaves in hydrophytes are thin and ribbon like.

                              iv.        Tissues usually have air spaces to keep the plants afloat.

                                 v.        Cuticle and stomata are absent in hydrophytes plants.


      Q61. What are Mesophytes? Write its adaptations.

      Ans. Mesophytes are that which we see around us. They grow in moderate climate. Most of the cultivated plants belong to this category. Example: mango, orange, guava etc.

      Mesophytic Adaptations are:

           i.        Roots are well developed.

         ii.        Stems are solid and freely branched.

       iii.        Leaves are large, broad and thin.

       iv.        Stomata are present.


      Q62. What are Xerophytes? Write its adaptations.

      Ans. Xerophytes are the plants that grow in deserts or in place which receives very less water. Example: cactus, euphorbia etc.

      Xerophytes Adaptations are:

                                   i.        Roots of these plants go deep into the soil in search of water.

                                ii.        Roots of these plants have numerous root hairs to absorb water.

                               iii.        Leaves are small and scale like.

                               iv.        Leaves are modified into spines. Example: cactus.

                                v.        Cuticle and stomata are absent in xerophytes plants.

                               vi.        Stems of these plants are thick and fleshy for conserving water. Example: cactus.


      Q63. What are the different types of aquatic habitats?

      Ans.  Different types of aquatic habitats are:

                                 i.        Marine habitat - This includes sea and ocean. Organisms found in this habitat are: whale, dolphin, shark, crab, seaweed, sea grass, red algae etc.

                               ii.        Fresh water habitat – This includes rivers, ponds, lakes and streams. Organisms found in this habitat are lotus, duckweed, water lily, moss, algae, fish, crocodile etc.

                               iii.        Coastal habitat – This is the place where the sea meets the land. Organisms found in this habitat are: oysters, crab, mangroves etc.

      Q64. What are the different types of terrestrial habitats?

      Ans. Different types of terrestrial habitats are:

                                 i.        Grasslands – Grasslands are the areas covered with grass, especially one used for grazing. Animal such as zebra, ostrich, elephant, lion, bison, fox, etc. are found in this habitat.

                                ii.        Deserts – These are dry areas with very less rainfall. Plants such as date palm, cactus, dessert willow tree, desert lily, prickly pear and animal such as rat, snake, camel, and scorpion are commonly found in this habitat.

                                iii.        Polar Regions – Regions close to poles are called Polar Regions. These regions are always covered with snow. Polar bear, penguin, reindeer, rabbit etc. are common in Polar Regions.

                               iv.        Mountain regions: Mountains are large landforms that stretch above the surrounding land in a limited area. Trees such as spruce, pines and animal such as big horn sheep, mountain goats, brown bear, black bear, grizzly bear, mountain lions and antelope etc. are found in mountain regions.