Page 434 - Primary Six Notes

Types of fertilization

There are two types of fertilization

1. External fertilization

2. Internal fertilization

1. External fertilization

This is where the female lays eggs and the male pours sperms

on them outside the mother’s body to fertilize them e.g. fish

and amphibians.

2. Internal fertilization

This is when eggs are fertilized inside the mother’s body after

mating.

Human sexual reproduction

 Fertilization takes place in the oviduct /fallopian tube.

 Immediately after fertilization, the zygote moves to the uter-

us.

 The zygote attaches itself onto the placenta with the help of

an umbilical cord. This process is called implantation.

 The placenta supplies the embryo with food nutrients and
oxygen. At the same time, it removes waste products.

 The umbilical cord transports food to the foetus and waste

products from the foetus to the placenta to be carried away

by blood.