For IGCSE O-Level Biology students Chapter 13

1. Reproduction in plants

2. Sexual & asexual reproduction
Sexual reproduction:
 Two parents
 Fusion of a female &
male cells (gametes)
 Parent & offspring are
not identical
 Slower
 Variation is present in
the same species
Asexual reproduction:
 One parent only
 No gametes are
produced
 Parent and offspring
are identical
 Faster
 No variation

3. Examples of asexual reproduction.
Budding in yeast
Nucleus
replicates
Nucleus
migrates to
one end
Part of the cell
grows into a
bud
The bud
separates
creating a new
cell

4. Examples of asexual reproduction.
Vegetative reproduction in potato plants

5. Examples of asexual reproduction.
Runners in strawberry

6. Sexual reproduction in plants
 To reproduce sexually plants have male
and female reproductive organs in their
flowers.
 The male part is called the stamen
 The female part is called the carpel

10. POLLINATION
It is the transfer of pollen grains from the anthers to the
stigma
Pollinating agents
Insects Wind

11. Differences between insect &
wind pollinated flowers
Insect pollinated Wind pollinated
 Have large colored
petals with guide lines
 Have a scent
 Have a nectary on which
insects feed
 Have a sticky stigma for
pollen grains to stick on it
 The female and male
organs are enclosed in
the flower
 Pollen grains are larger
with spikes to hold on
insect body
 Have small green petals,
no guide lines
 Have no scent
 Have no nectary
 Have a feathery stigma to
catch the pollen in the air
 The female and male
organs are hanging
outside the flower
 Pollen grains are smaller
& light weight to be carried
by wind

12. POLLEN GRAINS AS SEEN UNDER THE MICROSCOPE
Can you tell which belongs to insect pollinated flowers / wind pollinated flowers?

13. FERTILISATION
It is the joining of male and female cells to produce a zygote.
Ovary Fruit
Ovary wall Fruit cover
Ovule Seed

14. Seed structure
D

15. Seed-fruit dispersal
 If a seed lands next to the parent plant and
germinates it will compete with the parent
plant for nutrients in the soil.
 Most plants developed methods to
scatter/disperse their seeds to ensure they
land further away from the original plant.
 There are 2 main methods of seed
dispersal:
 Wind dispersal
 Animal dispersal

16. Wind dispersal
Parachute e.g. dandelion Winged fruits e.g. Acer

17. Animal dispersal
Hooked fruits e.g. Burdock and others

18. Animal dispersal
 Other fruits are large coloured and
fleshy/juicy to attract animals to eat
them, swallowing the seeds at the same
time.
 The seeds have hard indigestible testa
that pass out with faeces in a new area
away from original plant.
 Example of such fruits: apple, acorn,
strawberries…etc.

19. Seed germination
 Once a seed falls onto a suitable surface
it starts to grow.
 Conditions required for seed germination:
1. Suitable temperature
2. Oxygen
3. Water