Inside or outside

The idea

Animal gametes are sperm (male) and eggs (female); fish and frogs release them into water, where fertilisation and embryo development take place, while in birds and mammals sperm are deposited inside the female's body for fertilisation.

Hen and fish

A hen's egg and a fish's egg form in different ways.

Do all animals fertilise the egg in the same place?

• No, some inside the body and some outside
• Yes, all inside
• Yes, all outside

Sort the animals

Where does the male gamete join the female gamete?

Fertilisation sites

In some animals such as hens and cows, the male gamete joins the female gamete inside the female's body (internal fertilisation). In fish and frogs, the gametes join outside the body, in water (external fertilisation).

Internal: hen, cow (inside the body). External: fish, frog (outside, in water).

Notes

Internal: hen, cow. External: fish, frog.

Check yourself

Fertilisation inside the female's body is …

In which animal does fertilisation happen outside the body?

Frogs have …

In a cow, the male and female gametes join …

• internal fertilisation — correct. Yes!
• external fertilisation. External is outside the body.
• budding. Budding is asexual.
• Cow. Cow: inside the body.
• Fish — correct. Yes!
• Hen. Hen: inside the body.
• internal fertilisation. Frogs fertilise outside the body, in water.
• no fertilisation. Frogs have external fertilisation.
• external fertilisation — correct. Yes!
• inside the female's body — correct. Yes!
• in water. That is for fish and frogs.
• in the soil. In a cow, inside the body.