Life on the Earth

  • Question 45

    Write a brief note on man-made ecosystem?

    Humans being have changed the environment to a far greater extent than any other species on earth.
    i. In some instances, the modification is so profound that we call them man-made or artificial ecosystem.
    ii. Villages and cities, orchards and gardens, parks with their animals are man-made terrestrial ecosystem.
    iii. Large dams and reservoirs, lakes, canals are examples of man-made aquatic eco-systems.
    Question 46

    Explain agro-ecology.

    1. The study of the relation between agricultural crops and environment is called agro-ecology.
    2. The physical conditions as well as the biotic communities of different croplands vary widely.
    3. Since there are some common features that mark all croplands, they are generally called agro-eco systems.
    4. The physical conditions of the farm depend upon latitude, overall climatic and ecological factors.
    5. The type of crops depends upon the climatic season and choice of the farmer.
    6. Animal population of cultivated lands comprises earth worms, nematodes, domestic animals, insects and many birds.
    Question 47

    Discuss fresh water environment and mention plants and animals that live therein.


    The fresh water bodies are lakes and ponds. They vary in size from less than a hectares to hundreds of hectares. The relatively shallow lakes called eutrophic lakes have a rich accumulation of organic products.

    Streams and rivers: They differ widely in volume of water, speed of flow and oxygen content, etc. The nature and composition of flora and fauna depends on the source of the river and the land environment. Floating population of planktons are generally absent in such waters. Sediments are deposited on the river bed. The total volume of water is also larger. The surface gets more sunlight raising the temperature of water. The water often is muddy cutting down light at the river bed. Many reptiles, mammals and birds obtain their food from the water therein.

    Question 48

    State the relationship between animal life and vegetation in a region.

    There is a close relationship between animal life and vegetation in a region. Vegetation not only provides food but also suitable habitat for animals. Animals have to move from place to place in search of food. Animals in tropical forests are adapted to live among trees, for example apes and monkeys can climb trees because of their long limbs and small deer can move freely between trees. In the cold Tundra region animals have thick skins to protect them from cold.

    NCERT Book Store

    NCERT Sample Papers

    Entrance Exams Preparation