Name this life process

Reproduction
What is reproduction?
 Reproduction
• Reproduction (or procreation) is the
biological process by which new "offspring"
individual organisms are produced from their
"parents".

• Reproduction is a fundamental feature of all

known life
 Reproduction
Methods of reproduction
• Asexual
• Sexual
Asexual reproduction in potato
Asexual reproduction in potato
Asexual reproduction in hydra
 What could be the possible
difference between asexual and
sexual reproduction?
 Reproduction

Reproduction

Asexual Sexual
Produces identical off springs Produces genetically different off springs
 What is asexual reproduction?
• Asexual reproduction is a mode of
reproduction by which offspring arise from a
single parent, and inherit the genes of that
parent only

• No variation
Chromosome
Chromosome number
 Questions
• What is a gamete?
• What is a zygote?
• Why do gametes contain half the number of
chromosomes?
• What is a diploid cell?
• What is haploid cell? Give example
• When do cells divide by meiosis?
• What is the purpose of meiosis?
Reproduction in flowering plants
• Vegetative structures:
stems, roots and leaves
• Reproductive structures:
flowers
• Vegetative Propagation:
reproduction of vegetative structures
Structures of a typical flower:

Angiosperms reproduce sexually by producing flowers

How pollen is made
 Ovary
Green part - ovary
white part - ovule
Each ovule contains
nucleus which is the
female gamete
Why do bees visit a flower?
Wind pollinated flower- pollination
• Pollination: the transfer of pollen grains from
anthers to the stigmas of the same flower or a
different flower but of the same species
• external agents are needed –
• (1) by insect
• (2) by wind
• Comparison of wind-pollinated
and insect-pollinated flowers

wind-pollinated insect-pollinated
wind-pollinated insect-pollinated
Example: grass Example: Bauhinia
wind-pollinated insect-pollinated
Petals are dull and …large & brightly
much reduced in size coloured, conspicuous
to insects
wind-pollinated insect-pollinated
Petals are dull and …large & brightly
much reduced in size coloured, conspicuous
to insects
No scent or nectary Scent and/or nectary to
attract insect
wind-pollinated insect-pollinated
Petals are dull and …large & brightly
much reduced in size coloured, conspicuous
to insects
No scent or nectary Scent and/or nectary to
attract insect
Stigmas protrude …lie deep inside corolla
outside flower on long
styles
wind-pollinated insect-pollinated
Petals are dull and …large & brightly
much reduced in size coloured, conspicuous
to insects
No scent or nectary Scent and/or nectary to
attract insect
Stigmas protrude …lie deep inside corolla
outside flower on long
styles
Stigmas are feathery, …relatively small
giving them a large because they are easily
surface area to filter touched by insects
pollen from the air
wind-pollinated insect-pollinated
Anthers hang outside …lie inside flower to
flower on long filaments touch insects when they
so the pollens are easily come to collect nectar
released into the air
wind-pollinated insect-pollinated
Anthers hang outside …lie inside flower to
flower on long filaments touch insects when they
so the pollens are easily come to collect nectar
released into the air
Large number of pollens Less pollens because
are produced to offset high chance of
the high degree of successful pollination
wastage during dispersal and to reduce wastage
wind-pollinated insect-pollinated
Anthers hang outside …lie inside flower to
flower on long filaments touch insects when they
so the pollens are easily come to collect nectar
released into the air
Large number of pollens Less pollens because
are produced to offset high chance of
the high degree of successful pollination
wastage during dispersal and to reduce wastage
Pollen is smooth, light …larger and often have
& small and sometimes projections to adhere to
have wing-like insects
extensions to aid wind
transport
12.4.1 Fertilization &
Development in Flowering Plants
- pollen grains send out pollen tubes which grows
down the style & ovary, towards the micropyle
- pollen grains are attracted by sugars in stigma
and secrete enzymes to digest a pathway
through the style
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals &
stamens
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/ pericarp
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/pericarp
ii) ovule
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilization
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/pericarp
ii) ovule ⎯→ seed
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilization
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/pericarp
ii) ovule ⎯→ seed
iii) integuments
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/pericarp
ii) ovule ⎯→ seed
iii) integuments ⎯→ seed coat (testa)
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/pericarp
ii) ovule ⎯→ seed
iii) integuments ⎯→ seed coat (testa)
iv) fertilised egg
12.4.3 Development of Fruits and Seeds
Fate of floral parts after fertilization
Floral Part Fate after fertilizztion
(a) sepals, petals & All wither and drop off
stamens
(b) ovary Becomes the fruit
i) ovary wall ⎯→ fruit wall/pericarp
ii) ovule ⎯→ seed
iii) integuments ⎯→ seed coat (testa)
iv) fertilised egg ⎯→ embryo
Seeds

(Testa)
 What are the conditions required
for the seed to germinate?
https://learning.cambridgeinternational.org/classroom/course/view.php?id=3643
Conditions required for seed to
germinate
• 1. Temperature –
warmer temperatures enable enzymes
to work
• 2. Oxygen - enables seeds to respire
aerobically to supply energy for growth
• 3 Water - Water is required to activate the
enzymes to break down
• Starch - glucose
• Fats - fatty acids and glycerol
• Proteins - amino acids
Germination & Early Growth in Flowering Plants

Conditions necessary for seed germination

1. Water - taken up through the micropyle;
softens seed coat;
cotyledons swell up & burst through seed coat;
enzymes are activated to break down starch to
simple sugars and proteins to amino acids;
fats are converted into fatty acids & glycerol;
these dissolve in water & are transported to the
growing points of the embryo
• Glucose, fatty acids & glycerol provide
respiratory substrates from energy for
growth is released;
• Glucose is also used in the formation of
cellulose cell walls;
• Amino acids are used to form new
enzymes and structural proteins within
new cells.
 Questions
• What is the function of the flower?
• After pollination, how does the male gamete reach the ovule?
• What is the function of micropyle in a seed?
• What happens to each of the following after fertilization?
• Petal
• Stamens
• Zygote
• Ovule
• Integuments of the ovules
• Ovary
• What are the conditions essential for germination?
• What is the function of each of them in germination
• Protein
• Carbohydrates
• fat
 Advantages Disadvantage
Sexual Causes genetic variation Energy consuming
If environment changes, Two parents required
increased probability of Spread of diseases (STD)
high survival rate
Greater resistance to
diseases
Asexual Single parent required Not much genetic diversity
Less competition
Less energy
Quickly populates the
environment
Disadvantage of asexual
reproduction
 Hermaphrodite
• an individual in which reproductive organs of
both sexes are present
an organism, as an earthworm or plant,
having normally both the male and female
organs of generation.