Most sexually reproducing organisms are diploid, meaning they have two copies of every chromosome (maternal / paternal copy)
Fertilisation of two haploid gametes (egg + sperm) will result in the formation of a diploid zygote that can grow via mitosis
- In order to reproduce, these organisms need to make gametes that are haploid (one copy of each chromosome). This is the final product of meiosis I.
Fertilisation of two haploid gametes (egg + sperm) will result in the formation of a diploid zygote that can grow via mitosis
- If chromosome number was not halved in gametes, total chromosome numbers would double each generation (polyploidy)