Why is meiosis needed in species that reproduce sexually?

i) Meiosis is a type of cell division wherein the number of DNA of the germ cells is reduced to half and the full number of DNA is restored only after the male and female germ cells have fused together.


ii) Species that reproduce sexually rely on the fertilization of the eggs in the female by the sperms from the male.


iii) DNA from both the parent germ cells combines during sexual reproduction.


iv) If the copies of DNA are to be combined then this would result in double the amount of DNA every time a new individual is born. This is not possible as the individual would not survive.


v) Since the two germ cells need to fuse together for the production of an offspring, it is necessary that the number of DNA in both the cells is half so that when the cells fuse, the correct full number can be restored.


vi) For this reason, meiosis is needed during sexual reproduction so that the amount of DNA can be reduced into half in the germ cells which makes it possible for the two germ cells to fuse and have a stable amount of DNA in the offspring.


22