Bringing Sperm and Ova Together:
The female gamete, as we’ve mentioned, is the
ovum. The terms “ovum” and “egg” are often used as if they’re interchangeable, but this really isn’t the case. An
egg is an ovum (especially a
fertilized ovum – a zygote), plus any supporting cells or tissues that may be present in addition.
Fertilization can occur either inside the female’s body or outside of it. If the ova are fertilized outside the female’s body, this is known as
external fertilization. Typically, the female lays her eggs and the male sheds sperm over them as they’re laid or shortly afterwards. This is a quick and easy way to get eggs fertilized, but it has a number of disadvantages. The most obvious disadvantage is that external fertilization must take place in a wet environment, else the eggs will dry out and die.

Most amphibians such as these Wood Frogs (Phylum Chordata) have external fertilization.
As the female expels her eggs, the male sheds sperm onto them.