Each organism continually interacts with its environment: environment affects the organism.
Consider the effects of pollutants in the atmosphere. They are often irritating to human health but the effects of atmospheric pollution on the biosphere may be less direct.
Today even the air is a resource that man must conserve . Under certain conditions, smokes and the wastes from gasoline engines produce a smog that is poisonous to all living things, including man who creates it.
Our environmental pollution has now reached the point that drastic measure must be undertaken. There is no new cave to move to and, if we continue our present course, we will be trapped.