On unit 4, we studied the human reproduction. Humans are vertebrate animals (we have a backbone), so we already know how vertebrates can reproduce.

Do you remember it?

Basically, there are 4 steps:

  1. The sperm and the ova are produced in the male and the female reproductive systems.

  2. Fertilization: it is when a spermatozoon and an ovule join to make a baby.

  3. Pregnancy: it is the development of the baby in the mother's uterus.

  4. Birth: it is when the baby is born.



Steps 1, 2 and 3 are common to all vertebrates. The difference comes with step 4: are all vertebrates born the same way? The answer is NO!!

Depending on how babies are born, we can make the difference between viviparous and oviparous vertebrates.

VIVIPAROUS VERTEBRATES

  • They grow inside their mother's womb.

Womb.jpg
DEVELOPMENT OF A HUMAN BABY
  • The babies drink their mother's milk.

  • The babies are born fully developed (their organs can work efficiently): if they are born before they are fully developed, they will die, because their organs are not ready to work.

  • Parents need to take care of the babies until they can look after themselves.


Mum looking after a baby.jpg
AT THE BEGINNING, PARENTS TRANSPORT THEIR CHILDREN


OVIPAROUS VERTEBRATES

  • They are born from eggs.

  • Some animals sit on their eggs to keep them warm until they hatch. Then, the parents take care of the babies until they can look after themselves.

  • Other animals abandon their eggs. When the eggs hatch, the babies can look after themselves.

Born from an egg.jpg
OVIPAROUS ARE BORN FROM EGGS

Time for the videos.

On the first video, you will watch how a cow is born.




On the second video, you will watch how a chicken develops inside an egg.





Time to play games to check what you have learned. Click here to go to the games section.