[Music] foreign [Music] ment the Earth is the home of human beings and other living organisms this is possible due to the presence of favorable living conditions which make up their environment the term environment refers to all the external conditions in which an organism lives it comes from the French word environa which means to surround it is used to describe everything such as places things people nature Etc it also includes things created by human beings the geographical elements can be broadly classified into two groups natural elements and human-made elements [Music] the natural elements such as mountains Rivers vegetation animals Etc are created by Nature this is called natural environment it includes the biotic and abiotic components the human-made elements such as agriculture Industries settlements means of Transport Etc are created by human beings therefore it is called human-made environment the two types of environments interact with one another they change in course of time from place to place these changes take place due to natural processes and human activities some of them are as the landforms are being Modified by various natural and human activities we experience changes in climatic conditions in different seasons every day some species of plants and animals become extinct and new species evolve the evolution of human beings was due to changes in the environment any changes in the natural environment causes variations in the human interatural environment in vice versa both biotic and abiotic components the biotic components comprise plants and animals whereas abiotic components comprise air water and soil we have already learned about the four major domains of the Earth lithosphere hydrosphere atmosphere and biosphere in class 6. let us refresh our knowledge about these four domains the rocky outermost layer of the Earth is called the lithosphere the term lithosphere means Rocky crust it includes crust an upper part of the mantle the average thickness of the lithosphere is about 100 kilometers lithosphere is very important because it provides land for building houses roads factories and for agriculture it is also an important source of minerals and power resources the water present on the earth's surface is referred to as the hydrosphere the different sources of water such as oceans Seas base Lakes Rivers Etc form the hydrosphere water supports all forms of life water is found in three states solid ice liquid water and gaseous water vapor fresh water is made available on land through the water cycle process the envelope of air which surrounds the Earth is called the atmosphere the atmosphere is held to the Earth by the force of gravity it contains life-giving oxygen for humans and animals and carbon dioxide for plants the atmosphere prevents the sun's harmful Rays from reaching the Earth's surface it controls the extremes of temperature during day and night without atmosphere our Earth would have been Barren like other planets the narrow Zone where the lithosphere hydrosphere and atmosphere meet and interact is called the biosphere the sphere supports life and is called The Living World the biosphere is small in size but it is estimated that about 15 lakhs of different species of organisms live in it the biosphere provides nutrients and resources to all living organisms ecosystem all living organisms interact with each other and are interdependent on one another they also interact with their physical environment the complex system of interactions between organisms and their physical environment in a particular area is referred to as an ecosystem the size of ecosystem varies greatly it can be as large as rainforests grasslands deserts Lakes Rivers or as small as a pond a typical pond ecosystem contains fish frogs algae what are lilies and other species that live in and around the pond most of the ecosystems are complex and contain thousands of interacting species these species interact with each other and also with the abiotic environment human beings are part of the environment in which they live they also able to adapt and modify the environment according to their needs with scientific and technological advancement they have succeeded in controlling and dominating nature the interaction of human beings with the environment T is complex in nature early humans adjusted themselves with the surroundings in which they lived most of their needs were fulfilled from the environmental resources with time the quality and quantity of human needs changed they started developing techniques and new ways to use environment past humans settled in the fertile plane of the river valleys to cultivate land they domesticated animals and learned to use fire for warmth and protection the invention of the wheels surplus food production and exchange of surplus Goods with others helped them to progress gradually humans started processing various raw materials to meet their needs the industrial revolution in Europe enabled large-scale production of goods this means of transport and communication improved and the world became a family thus many changes took place in our environment which were mostly due to natural processes and human activities in spite of all the developments the physical environment still provides human beings with their material needs the primary activities farming fishing Forestry and Mining still provide food and raw materials human beings and their activities also represent the greatest danger to the environment right from the dawn of human civilization people have not only used nature for their existence and fulfillment of needs but also exploited and misused it to a certain extent today the whole world is facing various problems due to technological and scientific development on one hand and overpopulation urbanization and industrialization on the other a perfect balance is needed between the natural and human environment a number of organizations with the help of scientists technologists and planners are working to solve the environmental problems facing the world it is important that all of us understand and learn to live and use environment in a harmonious way only then will a balance in nature be maintained [Music]