Fertilisation

• Ovulation happens from the ovary into the oviduct • Egg travels down the oviduct moved by cilia • The egg and sperm nucleus join. This is fertilisation • They form a cell called the zygote • The zygote moves down the oviduct and into the uterus • The zygote embeds in the wall of the uterus. This is called implantation

Day 0: fertilisation ( fusion of sperm nucleus and egg in the oviduct) Day 1: forms zygote (fertilisation only successful if the zygote successfully implants into the uterus lining ) Day 2: splits into 2 cells Days 3-4: splits into 4 cells and 8 cells Day 5: blastocyst Day 8-9: implantation

One egg is fertilised by one sperm and in later stages splits in 2 and they develop separately

When 2 eggs and 2 sperm come together and develop.

Asexual and sexual

The term use for a fertilised egg