Class 7 NCERT Solutions Geography Chapter 1 - Environment

(i) Plants, animals and human beings depend on their immediate surroundings and are also interdependent for their survival. Such relations of dependence and interdependence together form an ecosystem. In other words, an ecosystem is the system formed as a result of the interactions of all living organisms with each other, and with the physical factors of the environment in which they exist. They are all linked by transfer of energy and material.

(ii) The environment that consists of all objects created by nature is called natural environment. It includes land, air, water, plants and animals. In essence, it includes both the biotic and abiotic conditions existing on earth.

(iii) The major components of the environment are as follows:

(a)   Natural environment; that includes all natural objects like air, land, water, etc.

(b)   Human environment; that consists of human beings.

(c)    Human-made environment; that consists of objects created by humans like industries, roads, etc.

(iv) Buildings, roads, parks and industries are some examples of the human-made environment.

(v) The solid crust or the hard top layer of the Earth is known as the Lithosphere. It is made up of rocks and minerals and is filmed by a thin layer of soil. It is an irregular surface with a multitude of landforms like mountains, valleys, plateaus and plains. Such land forms are found over the continents as well as on the ocean floors.

(vi) Living organisms like plants and animals are the two major components of biotic environment.

(vii) Biosphere is the narrow zone of Earth where water, air and land interact with each other to support life.

(i) - (b) Aquarium

(ii) - (a) Land

(iii) - (c) Road

(iv) - (b) Growing Population

(i) – (d) Narrow zone where land, water and air interact.

(ii) – (a) Blanket of air which surrounds the Earth.

(iii) – (b) Domain of water

(iv) – (c) Our surroundings

(i) All living organisms depend on their immediate surroundings for survival. Human beings especially interact with their environment and modify it according to their needs and compulsions. The primitive man lived off the land without making many changes in the natural environment. However, as evolution progressed, human beings discovered new ways of using the natural phenomena for the betterment of their lives. The discovery of fire, the invention of the wheel, the development of the barter system and trade and commerce, the invention of the engine, the onset of the industrial revolution and the progress in transportation and communication proved important landmarks in the process of human growth. While undergoing this process of development, human beings had to continuously modify the three components of the environment - 'natural' (polluting the air by burning fuels), 'human' (establishing social, political and religious units) and 'human-made' (railways, roads, etc.).

(ii) Plants and animals depend on each other in a multitude of ways. Plants are consumed by animals. The plants also produce oxygen through the process of photosynthesis; which is necessary for the survival of living organisms on Earth. Forests provide the habitat for wild animals and forestwood is important for humans in a variety of ways (construction, shipping, furniture, etc.).

On the flip side, animals aid plants in the process of reproduction through their involvement in the pollination of seeds. The Nitrogen necessary for the plants is provided to them by the bacteria that reside in the soil and the roots of certain plants. The process of photosynthesis depends on natural phenomena like water, sunlight and carbon dioxide. The carbon dioxide is further provided by humans and animals through their respiration.