1) Polar bears are doing well.

2) Technology follows human need, some of which, as shown by Twitter, can be very stereotyped, quick, and explained post-hoc.

3) Every living creature modifies its environment.

4) Genes, by a variety of tricks, turn on or turn off with each passing generation, sometimes in response to environmental assets.

Back to your books, m'boy. And back to your commonsense observations...