Science glossary film: Fertilisation

The fusion of two sex cells to create a new organism. Fertilisation happens in different ways in different organisms, but always involves the fusion of an egg cell from a female with a sperm from a male, which leads to the development of an embryo. Mammals use internal fertilisation, and fertilise only a small number of eggs. Plants and many marine creatures tend to use external fertilisation, and may fertilise thousands or even millions of gametes at once.

Fertilisation happens in different ways in different organisms, but always involves the fusion of an egg cell from a female with a sperm from a male, which leads to the development of an embryo. Mammals use internal fertilisation, and fertilise only a small number of eggs. Plants and many marine creatures tend to use external fertilisation, and may fertilise thousands or even millions of gametes at once.