Give your example of how the whole natural complex changes as a result of a change in one component.

Probably, such striking examples cannot be found so that everything is so global. There are small changes that a person brings. Some chemical plant is capable of destroying a lot around itself. Otherwise, nature has the property of adaptation. If you kill all the mosquitoes near some lake, of course it will affect the fish. But over time, they will adapt, they will eat something else. Even their disappearance can also be replaced or covered up with something, and you will not encounter serious consequences. Time will tell.