types of mutation

i'm trying to discover the history of the discovery of mutation for my novel.

In the novel, which takes place at the turn of the nineteenth/twentieth century, the characters are on Mars without adequate protection from radiation, so they're all dying of radiation sickness and don't know it. (It's complicated.)

When did people start understanding genetic mutation?

In the course of researchy googling, I came across this diagram to the left. I have no idea what it means, but it looks cool.

I wonder, do we have a mechanistic view of the universe because our science makes it seem that way, or do we have a mechanistic view of the universe because our most obvious metaphors for physical processes are machines, and then we draw diagrams that make stuff look like machines?

I don't believe that chromosomes look like this, no matter what you say. LA LA LA LA I'm not listening!