Does meiosis occur before or after fertilization?
Meiosis occurs before fertilization.
Meiosis is a reduction division. That means that meiosis produces gametes by reducing the number of chromosomes in half.
After meiosis, egg cells end up with half the number of chromosomes, and after meiosis, the sperm cells also end up with a matching other half.
Then the full number is restored once the sperm cell and the egg cell join up (fertilization).
So meiosis produces gametes (sex cells), each with half of the full number of chromosomes.
Then the egg cell and the sperm cell unite (fertilization), producing a zygote with the full number of chromosomes.
Here is an image of meiosis followed by fertilization