Internal Fertilisation

• Internal fertilization involves the fusion of gametes (egg and sperm) inside of the body of a parent
• This requires a method by which the gamete of one parent can be introduced inside the body of another (e.g. copulation)
• Terrestrial animals typically use internal fertilization so as to prevent exposure and desiccation of gametes or embryos
• Internal fertilization offers more protection to the gametes and embryos, but at a potential survival cost to the parent

In vitro fertilisation (IVF) refers to fertilisation that occurs outside of the body (in vitro = 'in glass’) [extracorporeal]