Year 7B Reproduction
© Tony P. Thould
September 2000
REPRODUCTON
In order for a plant or animal species to
survive they must reproduce.
Most plants and animals reproduce by
sexual reproduction which involves a
male sex cell joining with a female sex
cell. This is called fertilisation.
1. Why do some animals/ plants produce
only a few young whilst others produce
hundreds or thousands?
2.
What is an endangered species?
3. What is the difference between
Internal and External Fertilisation?
4. In what ways can Man help Plants /
Animals to survive?
Minimum you must answer is Questions 1,2 and 3.
AN OVUM CELL
Nucleus
Contains the female
set of chromosomes.
Allows only one
sperm inside before
blocking any other
ones from getting in
Cell Membrane
A SPERM CELL
Tail for
swimming
Acrosome to make a hole
in the ovum wall for the
sperm to get into the ovum
Mitochondrion to make
energy to move the tail
Nucleus with
male
chromosomes
Its job is to fertilize the ovum ( egg ) cell
Test
The Sperm cell
uses its tail to swim
to the Ovum
The Acrosome dissolves
a hole in the Ovum wall
and one Sperm enters
Fertilisation
FERTILIZATION
Pollen
Carries the
Male
Chromoso
mes in its
Nucleus
+
Ovule
Contains
the Female
Chromoso
mes in its
Nucleus
These are each a HALF SET of
Chromosomes so that when they
join together they form a
WHOLE SET in the seed.
=
Seed
A Fully
Fertilized
Ovule
FERTILIZATION
Sperm
Carries the
Male
Chromoso
mes in its
Nucleus
+
Ovum
Contains
the Female
Chromoso
mes in its
Nucleus
These are each a HALF SET of
Chromosomes so that when they
join together they form a
WHOLE SET in the seed.
=
Foetus
A baby with
a full set of
Chromosom
es
FERTILIZATION
There are two types of fertilisation :EXTERNAL
INTERNAL
This takes place
outside the female
body e.g. Frogs,
where the female lays
her eggs in water and
the male sheds his
sperm over them
This takes place
inside the female
body e.g. Man, where
the sperm are placed
inside the females
body and they swim
to the Ovum.
EXTERNAL FERTILISATION
Fertilisation takes place outside the females body
Male releases his
sperm into the
water nearby
The female lays her eggs
in a shallow hollow in the
sea bed
GERMINATION
Once the seeds have been dispersed they need
the right conditions to start growing into a
new plant - Germination.
These conditions are:•Warmth
•Moist
•Air
•Light/Dark
THESE ORGANS HELP WITH
REPRODUCTION
The male sex organs are made up from the
Penis, Testes and Scrotum. The Testes
make Sperm which contain the male genes.
The Penis places the sperm as near as it
can to the female’s egg ( Ovum )
The female sex organs are made up
from the Ovaries, Vagina, Uterus and
Oviduct. The ovaries make the Ovum
which contains the female genes. The
Uterus ( womb ) holds the developing
baby.
THE MALE SEX ORGANS
Pubic Bone
Erectile
Tissue
Bladder
Seminal
Glands
Sperm Duct
Penis
Testicle
THE FEMALE SEX ORGANS
Oviduct
Ovum
released
from the
ovary
into the
Oviduct
Ovary
Uterus or
Womb
Cervix
Vagina
In a flowchart draw and
label the path taken by a
Sperm Cell from leaving
the Testicle to fertilising
the Ovum Cell
THE MAIN PARTS OF A FLOWER
Petal
Stigma
Anther
Style
Stamen
Carpel
Filament
Ovary
Sepal
Ovule
Test
THE FUNCTIONS OF THE MALE PARTS
Anther
Stamen
Makes pollen which has
the male genes in it
Filament
Different plants
have different
numbers, shape and
sizes of Stamens
Holds the Anther up in
the air so that visiting
insects brush against it
Test
THE FUNCTIONS OF THE FEMALE PARTS
Stigma
Style
Carpel
Ovary
Test
Ovule
A sticky surface
where pollen stays
when visiting insects
brush against it.
Guides the pollen
tube down to the
Ovary.
Makes the Ovules
which contain the
female genes.
Forms the fruit.
THE FUNCTIONS OF THE MALE PARTS
Stamen
Different plants
have different
numbers, shape and
sizes of Stamens
THE MENSTRUAL CYCLE
Every month once puberty has been reached,
an egg or Ovum is released from one of the
ovaries in the female. This is called Ovulation.
If the Ovum is not fertilised then it leaves
the body through the Vagina along with the
lining of the Uterus which had become
thicker and richly supplied with blood.
This happens every month and is known as a
Period or Menstrual Cycle.
Day 28
Day 7
THE
MENSTRUAL
CYCLE
Day 21
Day 14
THE MENSTRUAL CYCLE
Oviduct
Week One
An Ovum is made
in the Ovary ready
to be released into
the funnel of the
Oviduct.
Ovary
Uterus
Vagina
THE MENSTRUAL CYCLE
Week Two
The Ovary releases
the Ovum into the
funnel of the
Oviduct. This is
Ovulation.
The Uterus wall thickens
ready for the fertilised Ovum
THE MENSTRUAL CYCLE
Week Three
The Ovary travels
down the Oviduct
towards the
Uterus.
The wall of the Uterus is
well supplied with blood.
THE MENSTRUAL CYCLE
Week Four
As the Ovum was
not fertilised, the
Uterus wall is shed
with the Ovum the Period.
THE MENSTUAL CYCLE
Once the period has finished the whole
cycle begins again and continues each
month as long as the Ovum is not fertilised.
To prevent the fertilisation of the Ovum
many couples take precautions which
stops the Sperm reaching the Ovum -
Contraception
EARLY PREGNANCY
The Embryo ( baby
) is held in the wall
of the Uterus and is
joined to the
Placenta by the
Umbilical Cord.
The baby gets food and oxygen from the mothers
blood through the Placenta. It also gets rid of waste
into the mothers blood through the Placenta
THE PLACENTA
The Placenta forms a barrier between the
blood of the mother and the baby but allows
substances to pass between them.
Placenta
THE PLACENTA
Oxygen, sugar, protein, vitamins, minerals,
water, antibodies all pass from the mothers’
blood, along the Umbilical Vein in the
umbilical cord to the baby.
Placenta
THE PLACENTA
Placenta
Waste products such as Carbon Dioxide,
Urea and excess salts pass from the baby
along the Umbilical Artery in the unbiblical
cord to the Placenta and into the mothers
blood so that her body can get rid of it.
THE PLACENTA
The Umbilical Cord
carries food and Oxygen
to the baby and waste
away.
Food and
Oxygen in
the mothers
blood
Placenta
Waste food and
Carbon Dioxide
THE PLACENTA
Unfortunately, some harmful substances can
pass from the mothers blood into the baby
e.g. Alcohol, Drugs, Nicotine and AIDS
Placenta
THE AMNION
This is a bag that surrounds the baby and is
filled with a fluid which protects the baby
from bumps and bangs.
Placenta
The Amnion
NINE MONTHS LATER
Placenta or
Afterbirth
Cervix
The baby is ready to be born. The head is
engaged - in the right position for birth, at
the mouth of the Uterus, the Cervix.
Adolescence
When children reach their teens
many physical and emotional
changes take place which some
of them find difficult to come to
terms with.
PRIMARY SEXUAL CHARACTERISTICS
Males
Females
Secondary Sexual Characteristics
These are changes in the bodies of boys
and girls when they are changing from a
boy to man and girl to woman
Physical Changes
Puberty is the period when certain physical
changes take place in the male and female
body usually in early teens.
Males
Females
• Pubic facial and
armpit hair grows
• Pubic and armpit hair
grows
•Voice breaks and
deepens
•Breasts develop and
body more curved
•More muscular body
•Menstrual cycle begins
giving her monthly
periods
•Sperm produced by
testes.