There are two main ways that organisms can reproduce:
Some plants can reproduce both sexually and asexually. However, most animals rely on sexual reproduction and all bacteria reproduce asexually.
Sexual reproduction is a process that involves the fusion of the nuclei of male and female gametes (sex cells). This process is also called fertilisation and it forms a zygote (a fertilised egg).
As there are two parents, the offspring are genetically different, containing a mixture of the parent’s genes. Therefore, we inherit genes from both of our parents. This results in a lot of variation over generations.
A normal human cell has 46 chromosomes. Whereas a human gamete only has 23, which is half of the genetic material. So, when the two gametes fuse together, the zygote has 46 chromosomes.
Meiosis is a type of cell division that produces gametes.
Asexual reproduction only involves one parent, and it does not involve fertilisation or sex cells. Therefore, there is no fusion of gametes or mixing of genetic material. All of the offspring are identical clones of each other and the parent.
As asexual reproduction does not involve gametes, meiosis does not take place. Instead, only mitosis is involved.