Why is the process of mitosis and meiosis both important to a living organism.What would happen if meiosis did

I know it doesn't occur in my cell cutlure.  I also know that it doesn't occur in bacteria, yet they grow like mad.

If meiosis didn't occur, you wouldn't have diversity. Mitosis always results in creating 2 cells that are genetically IDENTICAL to the mother cell. In meiosis, you have cross-over of chromatids and independent alignment of chromosomes so it results in four genetically DIFFERENT cells (called gametes). Not to mention that sexual reproduction is based on meiosis so it wouldn't happen in the first place. Every species would have to reproduce asexually and so every individual would be exactly the same as the others.

Also, mutations occur during meiosis a lot more often than during mitosis. Mutation is one of the mechanisms through which natural selection (and evolution) take their course. So instead of species changing, they would stay the same for extremely long periods of time (if you wouldn't consider genetic drift, gene flow and geographical separation which I forgot how it's called).

If meiosis did not occur there would be no such thing as natural selection, species would not be able to adapt to changing environments, and they would eventually die off. It would also make artificial selection impossible, which would mean there would be no such thing as breeding.

Basically, evolution would not occur. There would be fixity of species