Bellringer-October 1, 2014
Write under exit slip
1) How do flowers reproduce?
2) Do flowers have separate male and female
organs?
3) How do monocot and eudicot flowers differ?
Flowers/Reproduction
Aquaponics
Flower
• Sexual reproductive structure
• Produces egg and sperm
• Fertilization takes place inside the
flower
The flower: the defining
structure of angiosperms
 Reproductive structure:
pollen transfer; specialized
shoot with modified leaves
 Sepals: enclose flower
before it opens
 Petals: attract pollinators
 Stamens: male sex organs;
anther (produces pollen),
filament
 Carpels or Pistil: female
sex organs; includes
stigma, style, ovary, ovules
Female
reproductive
organ
Pistil or Carpel
*Stigma –top of the pistil,
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
Pollination
• Flowers/fruits can be carried by wind,
water, or animals to new locations,
enhancing seed dispersal
(a) Wings enable maple fruits
to be easily carried by the wind.
(b) Seeds within berries and other
edible fruits are often dispersed
in animal feces.
Figure 30.9a–c
(c) The barbs of cockleburs
facilitate seed dispersal by
allowing the fruits to
“hitchhike” on animals.
Pollination: Transfer of mature pollen grains from the
anther to the stigma
• When a pollen grain lands on the stigma, it
germinates and a pollen tube grows down
through the style to an ovule (egg)
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)
*Self pollination –pollen from same flower
*Cross pollination – pollen from a different flower
- more variation
• 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
Fruits
• Form when ovary with ovules
(eggs) ripens
• May be dry and hardened (nuts)
• May be enlarged and fleshy
(berries, apples, tomatoes)
…TASTY!!!
• Used to help disperse seeds