Transcript Reproduction in Flowering Plants

Reproduction in Flowering
Plants
WALT – Explain how plants
reproduce Sexually
Mr. Stuart
Living Environment
• Identify and draw, using a hand lens if
necessary, the
• sepals,
• petals,
• stamens,
• anthers, carpels,
• ovaries and
• stigmas of one, locally available, named,
insect-pollinated, dicotyledonous flower,
Sexual Reproduction
• Using the gametes from 2 parents to
produce genetically unique individuals
Flower
• Sexual reproductive structure
• Produces egg and sperm
• Fertilization takes place inside
the flower
Which is the most accurate
statement?
The principal role of a flower in
the life
cycle of a plant is:
•
•
•
•
(a) attracting insects
(b) producing seeds
(c) producing pollen
(d) producing nectar
Female
reproductive
organ
Pistil/ Carpel
*Stigma –top of the carpel,
Sticky surface for pollen to
stick to
*Style – connects the stigma
to the ovary
*Ovary –contains ovules
( eggs)
Male
reproductive
organ
Stamen
*Anther – produces sperm
nuclei by meiosis. Sperm
nuclei are enclosed by
pollen grains.
*Filament – holds the anther
up
Pistel = many Carpels
• Female
• Male
1) What features of flowers might attract insects?
2) Which part of the flowers become a the seed and be the fruit?
Draw an accurate diagram of a
flower and include both Male/
Female Organs
• Pg 67
http://www.bbc.co.uk/bitesize/standard/biol
ogy/world_of_plants/growing_plants/revisio
n/4/
Pollination
Pollination
WALT –
• Explain the Transfer of mature pollen
grains from the anther to the stigma using
-wind
-insects
-birds & other animals
• Name the agents of pollination
• Compare the different structural
adaptations of
• insect-pollinated and wind-pollinated
flowers
• Describe the growth of the pollen tube and
its entry into the ovule followed by
fertilisation (production of endosperm and
details of development are not required)
• and examine the pollen grains under a
light microscope or in photomicrographs
• Pollination as the transfer of pollen grains
from the male part of the plant (anther of
stamen) to the female part of the plant
(stigma)
Draw in your books
• Cross Pollination
*Self pollination –pollen from same flower
*Cross pollination – pollen from a different flower
- more variation
Because nature doesn’t like self
pollination, often it is rejected
• When a pollen grain lands on the
stigma, it sticks and a pollen tube
grows down through the style to an
ovule (egg)
Wind v Insect Pollination
• Wind pollinated flowers are different in
structure from insect pollinated ones.
• [You need to be able to explain the main
differences. This table will help to make
these clear for you]
Insect pollinated
flowers - rose
sweet pea
Wind pollinated
flowers - ragweed
Insect Pollinated
Wind Pollinated
Insect Pollinated
Wind Pollinated
Insect Pollinated
Wind Pollinated
large, brightly coloured small petals, often
petals - to attract
brown or dull green - no
insects
need to attract insects
large, brightly coloured petals - to
attract insects
small petals, often brown or dull
green - no need to attract insects
often sweetly scented - no scent - no need to
to attract insects
attract insects
often sweetly scented - to attract insects
no scent - no need to attract insects
usually contain nectar - to attract insects
no nectar - no need to attract insects
moderate quantity of pollen less wastage than with wind
pollination
pollen produced in great
quantities - because most
does not reach another flower
wastage than with wind pollination
flower
pollen very light and
pollen often sticky or spiky -smooth - so it can be blown
to stick to insects
in the wind and stops it
clumping together
wastage than with wind pollination
because most does not reach another
flower
pollen often sticky or spiky - to stick to
insects
pollen very light and smooth - so it can
be blown in the wind and stops it
clumping together
anthers firm and inside
flower - to brush against
insects
anthers loosely attached
and dangle out - to release
pollen into the wind
Insect Pollinated
Wind Pollinated
large, brightly coloured petals - to attract small petals, often brown or dull green insects
no need to attract insects
often sweetly scented - to attract insects no scent - no need to attract insects
usually contain nectar - to attract insects no nectar - no need to attract insects
moderate quantity of pollen - less
wastage than with wind pollination
pollen produced in great quantities because most does not reach another
flower
pollen often sticky or spiky - to stick to
insects
pollen very light and smooth - so it can
be blown in the wind and stops it
clumping together
anthers firm and inside flower - to brush anthers loosely attached and dangle out
against insects
- to release pollen into the wind
stigma inside the flower - so stigma hangs outside the
that the insect brushes
flower - to catch the drifting
against it
pollen
Fertilization
• The sperm travels through the pollen tube to the
ovule. The sperm & egg fuse forming the zygote
(fertilized egg) –this grows into the plant embryo
(cells grow by mitosis)
• The ovary and zygote (fertilized ovule)
develop and ripen.
*The ovule forms the seed and the ovary
forms the fruit.
• A fruit is a ripened ovary
Germnination
WALT – Understand the process of
germination
The plant embryo uses food stored in the
cotyledon of the seed until it develops
leaves for photosynthesis
• Cotyledon – Leaf inside seed that supplies
food to growing embryo
Seedling
micropyle –opening in ovule where pollen tube attached
and sperm entered
hilum –scar where ovule attached to ovary
radicle –embryonic root
Epicotyl – grows above the cotyledons and gives
rise to the leaves.
Hypocotyl –below the point of attachment of the
cotyledon, develops into the stem.
Parts of a seed
• Dicot
Seed coat
Hypocotyl
Epicotyl
Cotyledons
Endosperm
• Monocot
Seed coat
Epicotyl
Hypocotyl
Cotyledon
Radicle
Seed Germination
Monocot
Dicot
Epigeous
Hypogeous
Radicle
Page
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Question 1 2 5 1 2 3 4 5 1 2 3 1 2 3 4 5
Marks
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