SURVIVAL

© T. P. Thould

April 2000

FERTILIZATION

For many plants and animals species to survive they need to reproduce by Sexual Reproduction.

This involves a Male and a Female each making a sex cell which can join together ( FERTILIZATION )and form a new individual.

THE MAIN PARTS OF A FLOWER

Sepal

Stamen

Petal

CarpelFilament

Anther

Stigma

Style

Ovary

TestOvule

THE FUNCTIONS OF THE MALE PARTS

Stamen

Anther

Filament

Makes pollen which has the male genes in it

Holds the Anther up in the air so that visiting insects brush against it

Different plants have different numbers, shape and sizes of Stamens

Test

THE FUNCTIONS OF THE MALE PARTS

Stamen

Different plants have different numbers, shape and sizes of Stamens

THE FUNCTIONS OF THE FEMALE PARTS

Stigma

Style

Ovary

Carpel

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.OvuleTest

POLLINATIONBefore fertilizion can take place. The pollen grains carrying the Male Chromosomes must get to the female part of the flower I.e. from the Anther to the Stigma. This is POLLINATION

Anther Stigma

POLLINATIONPOLLINATION can be by Insects, in which case the flowers are brightly coloured and smell.

If the flowers are dull and not easily seen then their pollen is carried by the Wind

Anther Stigma

POLLINATIONPOLLINATION can be either Self or Cross

SELF is when the Anther and Stigma are on the same plant.

CROSS is when they are on different plants

Anther Stigma

FERTILIZATION

PLANTS have flowers which have male and female parts that make the male and female sex cells.

The male part ( Stamen ) makes the POLLEN

The female part ( Carpel ) makes the OVULE

Pollen + Ovule = Seed

Fertilization

Once Pollination has taken place, the Pollen grain grows a tube carrying the Male Chromosomes , down the Style and through the Ovary wall.

Stigma

Style

Ovary

Ovule Pollen Tube

The Male Chromosomes join with the Female Chromosomes in the Ovule.

This is FERTILIZATION

FERTILIZATION

Pollen + Ovule = Seed

Carries the Male

Chromosomes in its Nucleus

Contains the Female Chromosomes 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.

A Fully Fertilized

Ovule

SEED DISPERSAL

Most plant have a way of dispersing their seeds so that they germinate and grow well away from the parent plant.

WHY?

Two ways some plants use to disperse their seeds is by:-

SEED DISPERSAL

1. Animals

2. Wind

How could the above seed be changed so that it could be dispersed by

a) An Animal b) The windSolution

SEED DISPERSAL

How are these seeds dispersed - what is it about them that gives you the answer?

A B

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

Bladder

Seminal Glands

Sperm Duct

Testicle

Penis

Erectile Tissue

Pubic Bone

THE FEMALE SEX ORGANS

Ovary

Uterus or Womb

Cervix

Vagina

Ovum released from the ovary into the Oviduct

Oviduct

FERTILIZATION

Sperm + Ovum = Foetus

Carries the Male

Chromosomes in its Nucleus

Contains the Female Chromosomes 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.

A baby with a full set of

Chromosomes

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.

THE MENSTRUAL CYCLE

Week One

An Ovum is made in the Ovary ready to be released into the funnel of the

Oviduct.

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

Week Three

The Ovary travels down the Oviduct

towards the Uterus.

THE MENSTRUAL CYCLE

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.

Day 7

Day 14Day 21

Day 28

THE MENSTRUAL

CYCLE

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 stoops 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

Food and Oxygen in

the mothers blood

Waste food and Carbon Dioxide

The Umbilical Cord carries food and Oxygen to the baby and waste away.

Placenta

THE PLACENTA

Placenta

The Placenta forms a barrier between the blood of the mother and the baby but allows substances to pass between them.

THE PLACENTA

Placenta

Unfortunately, some harmful substances can pass from the mothers blood into the baby e.g. Alcohol, Drugs, Nicotine and AIDS

THE AMNION

Placenta

This is a bag that surrounds the baby and is filled with a fluid which protects the baby from bumps and bangs.

The Amnion

NINE MONTHS LATER

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.

Cervix

Placenta or Afterbirth