As mentioned in the last lecture, the earth is a dynamic place. Change, not stasis, is the norm. Changes are not all human-induced, and they are all not negative. The concept of conservation is, therefore, philosophically and scientifically flawed.
Conservation means to retain or keep as is.
Take, for instance, the eruption of Mt. St. Helens. The eruption resulted in thousands of hectares of cropland being covered with ash. Initially this was an aesthetic and economic disaster to some people. Subsequent years proved otherwise. The ash soon became invisible as crops grew profusely, resulting in record high crop yields and hence profits.