Stages of Galactic Intelligence

Imagine the history of the galaxy with respect to extraterrestrial intelligence. Very early there were only first generation stars, no heavy metals and therefore no possibility of life, much less intelligence. That's Stage One. In Stage Two planets with heavy metals form from the starstuff processed in the previous generation of stars, life arises and evolves, but It's quite some time before a technical intelligence developes. In Stage Three, radiotélescopes are invented, radio contact among...

 Resistance to Insecticides and Herbicides as Evolution

Still other species have adapted via selection to human-caused changes in their environment. Insects have become resistant to DDT and other pesticides, plants have adapted to herbicides, and fungi, worms, and algae have evolved resistance to heavy metals that have polluted their environment. There almost always seem to be a few individuals with lucky mutations that allow them to survive and reproduce, quickly evolving a sensitive population into a resistant one. We can then make a reasonable ...