Sexual reproduction in the fungi consists of three sequential stages: plasmogamy, karyogamy, and meiosis. The diploid chromosomes are pulled apart into two daughter cells, each containing a single set of chromosomes (a haploid state). ... In most fungi the zygote is the only cell in the entire life cycle that is diploid.
If red light is shined on a population of red walking beans then they would not be as red as when started because they need light to survive and red light is present but they reflect it until they need it to survive.
Mutations that naturally occur can change phenotype and if it is beneficial to the species then it will be past on if it is no then it will die before passing it on.