Life has evolved from simple stages to more complex ones, and so have the reproduction mechanisms.
Initially the reproduction was a replicating process that consists in producing new individuals that contain the same genetic information as the original or parent individual.
This double-chromosome stage is called "diploid", while the single-chromosome stage is "haploid".
Sex en france
Sexual reproduction in eukaryotes is a process whereby organisms form offspring that combine genetic traits from both parents.
Chromosomes are passed on from one generation to the next in this process.
Some of the many plausible theories include: that sex creates variation among offspring, sex helps in the spread of advantageous traits, that sex helps in the removal of disadvantageous traits, and that sex facilitates repair of germ-line DNA.
Sexual reproduction is a process specific to eukaryotes, organisms whose cells contain a nucleus and mitochondria.
Some bacteria use conjugation to transfer genetic material between cells; while not the same as sexual reproduction, this also results in the mixture of genetic traits.