<P> Because the number of chromosomes is halved during meiosis , gametes can fuse ( i.e. fertilization ) to form a diploid zygote that contains two copies of each chromosome , one from each parent . Thus , alternating cycles of meiosis and fertilization enable sexual reproduction , with successive generations maintaining the same number of chromosomes . For example , diploid human cells contain 23 pairs of chromosomes including 1 pair of sex chromosomes ( 46 total ) , half of maternal origin and half of paternal origin . Meiosis produces haploid gametes ( ova or sperm ) that contain one set of 23 chromosomes . When two gametes ( an egg and a sperm ) fuse , the resulting zygote is once again diploid , with the mother and father each contributing 23 chromosomes . This same pattern , but not the same number of chromosomes , occurs in all organisms that utilize meiosis . </P>
<P> Because the number of chromosomes is halved during meiosis , gametes can fuse ( i.e. fertilization ) to form a diploid zygote that contains two copies of each chromosome , one from each parent . Thus , alternating cycles of meiosis and fertilization enable sexual reproduction , with successive generations maintaining the same number of chromosomes . For example , diploid human cells contain 23 pairs of chromosomes including 1 pair of sex chromosomes ( 46 total ) , half of maternal origin and half of paternal origin . Meiosis produces haploid gametes ( ova or sperm ) that contain one set of 23 chromosomes . When two gametes ( an egg and a sperm ) fuse , the resulting zygote is once again diploid , with the mother and father each contributing 23 chromosomes . This same pattern , but not the same number of chromosomes , occurs in all organisms that utilize meiosis . </P>
when does the transition from haploid to diploid take place
when does the transition from haploid to diploid take place
When two gametes ( an egg and a sperm ) fuse
When two gametes ( an egg and a sperm ) fuse