How do the direct and indirect effects of natural conditions on humans differ from each other?

Human activity directly or indirectly affects the number of natural populations of animals and plants, causing the growth of populations of some species, destroying others, and the death of others. The direct impact of man is in the direct destruction of species. This is deforestation, the desire to definitely catch a bright or unusual butterfly, the desire to take a huge bouquet of flowers, excessive shooting of animals on the hunt.

The indirect effect of people on living nature is to pollute the habitat of organisms, to change it. Thus, the populations of aquatic plants and animals are severely damaged by water pollution. For example, the number of the Black Sea population of dolphins is not recovering, since due to the huge amount of harmful substances entering the sea waters, their mortality is high.