Reproduction - Livingstone High School

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Transcript Reproduction - Livingstone High School

R EPRODUCTION Reproductive Parts and Fertilisation

Q UESTIONS  How do you think a baby is formed?

 What do you think are the important things both parents will pass on to their child during the formation of a baby?

R EPRODUCTION IN HUMANS Well, before a human can reproduction sexually, certain organs in the body occur in humans?

R EPRODUCTIVE S YSTEM  Which part of the human body are involved in sexual reproduction?

M ALE SEX ORGAN  In the male, the male sex organ plays an important role in sexual reproduction.

 The testes produce millions of sperms which can only be seen under a microscope.

R EPRODUCTIVE SYSTEM - M ALE

T HE R IBENA A NALOGY  In animals, the male gametes are known as  sperms  The female gametes are known as  ova or eggs

H UMAN S PERM Contains mitochondria which provides energy for the sperm’s activity Enables the sperm to swim towards egg

F EMALE SEX ORGAN • In the female, the female sex organ plays an important role in sexual reproduction.

• The ovaries produce eggs.

R EPRODUCTIVE SYSTEM – F EMALE

H UMAN E GG

H OW DOES HUMAN LIFE BEGIN ?

      The sperms in the testes of a male are transferred through the penis into the female’s vagina.

The sperms find their way to meet the egg inside the female’s body.

If a sperm meets an egg, they fuse. This is known as fertilisation.

Only one sperm can fertilise the egg.

The male and female are now the father and mother of the fertilised egg.

ERTILISATI ON

Mrs The resa Teo/ 2003

H OW DOES HUMAN LIFE BEGIN ?

 The fertilised egg divides to form more and more cells.

 These cells will eventually form the organs in the body of the developing baby.

H OW DOES FERTILISATION OCCUR ?

There is mating .

Sperms are introduced into the female through the vagina.

The sperms swim through the uterus to the oviduct towards the egg.

A sperm bumps into the egg.

The sperm penetrates the egg membrane.

The tail drops.

The egg membrane thickens to prevent other sperms from entering.

The sperm nucleus fuses with the egg nucleus.

H OW DOES HUMAN LIFE BEGIN ?

 As the baby develops inside the mother’s womb, the mother’s belly gets bigger.

 After about 9 months, the baby is born.

P ARENTS AND THEIR Y OUNG     The fusion of the sperm and egg results in a fully developed baby.

These two reproductive cells contain information about the characteristics of the father and the mother.

Through the reproductive cells, the characteristics of the parents are passed on to their young.

Thus, the characteristics of plants and animals are preserved in future generations, hence ensuring that their kind continues to exist. © 2009 Marshall Cavendish International (Singapore) Private Limited

H OW DOES IT HAPPEN ?

• Puberty - specific changes in the male  Boys usually reach puberty at an average age of 13 years.

 Sex organ starts to produce sperms  Shoulder and chest become broader  Voice breaks and deepens  Moustache and beard start to grow

H OW DOES IT HAPPEN ?



Puberty

- Specific changes in the female  When a baby girl is born, the ovaries already contain around 400 000 ova or eggs.  Girls tend to mature two years earlier than boys (average age of 11)  When she matures, a small fraction of these eggs mature (approx. 450) and is released from alternate ovaries each month.

 Breasts develop  Hips widen  Undergoes the menstrual cycle

M ENSTRUAL C YCLE  It is a cycle that all mature girls go through.

 One cycle takes approximately

28 days

 Ovulation – thickening of uterus walls – menstruation.

Reproduction - Livingstone High School

Transcript Reproduction - Livingstone High School

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