There are changes in the environment which are brought by the man. They bring the changes in the physical, biotic conditions and the natural resources conditions. The humans have affected the physical conditions of earth in an adverse manner. He has cut the tress and farms. He has made roads, factories and highways. He has exploited the villages, towns and cities for its use. He has also made big buildings and railways. He has made canals, lakes and tanks to store water for its use. It helps in the irrigation and sewages. In doing so, they have disturbed the ecological balance of the nature. The biotic community consists of the plants, animals and micro organisms. They live together in the same habitat. They affect each other in one way or the other. The man affects the biotic community and is considered to be a prey. It acts on the carnivorous animals like lion, tigers etc. It acts as a predator for the herbivorous animals and includes the sheep, goat, deer and birds. It can also act as a host for some parasites. There are certain animals which are known as the inquilines and include the mice, lizards and cockroach. They move to the new house where the humans shift. There are domestic animals which depend on the humans for their survival. The human help is required for the cultivation of tomato, cabbage, wheat and maize. These are referred as cultigens. The dogs, cats and wild parrots have also been domesticated by the man. Similarity some plants have also been kept at home by humans. There are many organisms which are transplanted by the man. The carrot grass is also known as the Pathenium hysterophorus. It is cultivated in the India and it came into our country in the early 1950s. There are many plants and animals which are introduced by the man. He has introduced them so that they can meet his need. For example, bumble bee to the New Zealand and the merino sheep to Australia. Man has destroyed the common habitats of organisms and also caused the deforestation. The water is polluted by the use of industrial wastes and gases. They kill the aquatic animals. The insects are killed by the use of insecticides which also have an adverse effect on the birds. There is a degradation of the natural resources day by day. They have reached a critical stage as we depend fully on the fossil fuels for the survival. They can only last for some centuries only. The airplanes are causing an adverse effect on the atmosphere by releasing some pollutants. The land resources are affected by the soil erosion, increase in the salt content, acidification and alkalization of the soil along with the water logging ability of the soil. The production of land is also affected by the construction of dams, railways, and mining activities along with the urban encroachment. The mineral deposits are going to be depleted in the few decades. This may lead to the shortage of some important elements. For example, phosphorous is an essential element for the fertilizers and its deficiency can affect the growth of crops. The plant life and vegetation are severely affected by the deforestation and environmental pollution. The biggest threat to the animal life is caused by the destruction of their habitat, killing of animals for the leisure and the environmental pollution. So, a serious threat is caused on the natural resources. This change in the natural resources has caused an adverse effect on the environment. This has lead to the mental imbalance. Most of the ecologists have made a prediction that if the depletion of natural resources will go at this speed the extinction of man can also occur. There is a great dependence of man on the natural resources. It can be direct or indirect. So, the man cannot exist without them. Man must realize the importance of resources and should act according to it. The man is an important part of environment. He cannot live alone and requires interactions to exist in the biosphere. He must conserve the environment. If the environment is not conserved the human may expose to the environmental hazards.
As the resources are decreasing there are efforts by the government to ensure that there supply is not hampered in the future. For example, Brazil is the first country in this world to have alcohol based petrol which act as a fuel for the automobile. The ozone layer can be harmful as well as useful. The layer which is present near the surface of earth is hazardous. The layer which is present in the stratosphere filters the harmful rays and saves the human life.