Comment 2 by k_docks

So long as there is at least one breeding pair, mutations (beneficial) and natural selection, regardless if the habitat is natural or artificial, the genetic diversity should increase.

Evolution does not work like that. Within a species there are lots of genes in the species gene pool, which are not all within any particular individual. You only have to look at humans, dogs, cats etc to know that individuals vary in colour, size, proportions etc, so where an environment acts to select for a particular feature, - such as resistance to sunburn, in habitats like Africa. those with naturally resistant black skin, have as a result of millennia of evolution, come to dominate.

If evolution were true wouldn't there be information added to a genome all the time increasing it's genetic diversity?

Once there are no longer individuals containing those genes in the population, the species can no longer adapt to those conditions without taking thousands or millions of years to re-evolve them by mutations, - or possibly cross breeding with a related species which retains those genes. However, hybrid offspring are usually sterile, so this rarely works.

So long as there is at least one breeding pair,

The breeding of closely related individuals, such as brothers and sisters, resulting from this situation, greatly increases the chances of harmful, damaged genes pairing up and creating genetic diseases and deformities.