I think the issue with the non living things that exhibit life-like behaviors is that each thing exhibits only 1. Life exhibits all. Viruses need a host to replicate, but then so do many intestinal worms.

I like the "life exhibits ability to evolve." Sure, there are organisms that have been largely the same for millions of years (turtles, for instance). Bacteria have been around since the beginning. But that just means that certain organisms are adapted to be stable over time.

I look up at the sky at night and sense life, an energy beyond the physical. Is the Universe alive too?