Terry, as you point out, other species modify the environment. Indeed, every living organism modifies the environment; but the modifications, while they may be great, are limited in scope and, with notable exceptions among mammals, rarely oriented to a premeditated goal - certainly nothing like the extensively planned, organised and sophisticated efforts of humans.
Terry: "have humans always known how and why they were changing their environment? Do we even know today?"
- Yes, we know why we change the environment. Primarily to make the environment more conducive to survival >> healthy living >> etc (Maslow's hierarchy of needs) - including physical and psychological aspects; in a nutshell, because we perceive a benefit in the desired outcome.
- No, we evidently didn't, and almost certainly still don't, know the full implications that our activities have for the environment.
