The origin of sexual reproduction can be traced to early prokaryotes, around two billion years ago (Gya), when bacteria began exchanging genes via conjugation, transformation, and transduction.

How did reproduction system evolve?

Reproductive organs evolved with the development of gonads that produce sperm and eggs. These cells went through meiosis, an adaption of mitosis, which reduced the number of chromosomes in each reproductive cell by half, while increasing the number of cells through cell division.

Why did we evolve to reproduce?

The reason why, in terms of evolution, organisms have sex may seem rather obvious – they do it to reproduce. Clearly, natural selection must favour individuals who can reproduce over those who can't. ... For many species there is an alternative: asexual reproduction.