text: Meiosis takes place in two stages: Meiosis 1 and Meiosis 2.\nAt the end of meiosis 1, you have two haploid cells with double stranded chromosomes.\nAt the end of meiosis 2, you have four haploid cells with single stranded chromosomes.\n\nCrossing over- the stage of meiosis that allows for genetic variability- occurs when the chromatids form tetrads during prophase 1 of meiosis.  This is the only stage that this is able to take place.\n\nSexual reproduction has the benefit of genetic variability.  The coding that will most help the offspring is passed on more frequently than the coding that would give it no selective advantage.\nAsexual reproduction makes exact copies- it would take longer for the organism to adapt to a change in the environment, as it would have to mutate.  This could be very bad for the organism, as the species may die off before the mutation in the genes takes place.