Why is meiosis necessary in organisms that reproduce sexually?

Answer 1

meiosis is the division of sex gametes into 1n cells. This way, 2 X 1n cells (a sperm and an egg) can combine to form a 2n cell (a fertilized egg)

Answer 2

Sexually reproducing organisms are different from asexually reproducing ones b'coz of differences in the genotype of the parent and offspring. What i mean is that the offspring is not an exact clone of the parent, as it is in the case of say, bacteria.
The difference arises due to genetic recombination between the non-sister chromatids of homologous chromosomes during crossing-over in the pachytene stage. This kind of recombination is possible only if Meiosis occurs. So, Meiosis is necessary to generate diversity. Otherwise, we would all be clones. In sexually reproducing organisms, any change in the genotype can occur only due to mutation or horizontal gene transfer (conjugation, transduction, transformation).
This apart, Meiosis is also necessary to maintain Diploidy of the zygote.

Answer 3

The problem is that mitosis always gives cells that have 100% of the genetic information. That is why meiosis is necessary. Meiosis creates daughter cells which contain only half the genetic information of the parent cell.

Answer 4

Meiosis is necessary so that it provides all sex cells produced with a haploid (half) number of chromosomes As a result, when fertilization occurs, a resulting zygote appears with a full set of chromosomes. In humans, the full set is 46 chromosomes. The haploid number is therefore 23. By the way, I was long in search with someone who is interested in such things. Please add me to your contact list ([e-mail]), whoever you are; a boy or a girl. Thanks.

Answer 5

Without it, all the cells of the resulting "child" would have twice as many chromosomes as it's supposed to. In order to reap the benefit of sexual reproduction--the mixing up of DNA--the new organisms need to have half mom's DNA and half dad's, creating a new and unique (unless an identical twin) organism.

Just duplicating the parent, as in asexual reproduction, leaves less room for modification over time of the species, except by chance mutation.

Answer 6

during meiosis, the number of chromosomes are halfed to 23 so that when it combines to form the zygot it will form a normal, natural cell with 46 chromosomes.