bellringer -march 17, 2014
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Bellringer -March 17, 2014. How do flowers reproduce? Do flowers have separate male and female organs? How do monocot and eudicot flowers differ? . Flowers/Reproduction. Aquaponics. Flower. Sexual reproductive structure Produces egg and sperm Fertilization takes place inside the flower. - PowerPoint PPT PresentationTRANSCRIPT
Bellringer-March 17, 2014
1) How do flowers reproduce?2) Do flowers have separate male and female
organs? 3) How do monocot and eudicot flowers differ?
Flowers/ReproductionAquaponics
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 (Pistal): female sex organs; stigma, style, ovary, ovules
Pistil*Stigma –top of the pistil,Sticky surface for pollen to
stick to*Style – connects the stigma to
the ovary*Ovary –contains ovules ( eggs)
Stamen*Anther – produces sperm
nuclei by meiosis. Sperm nuclei are enclosed by pollen grains.
*Filament – holds the anther up
Female reproductive organ
Male reproductive organ
• Flowers/fruits can be carried by wind, water, or animals to new locations, enhancing seed dispersal
Figure 30.9a–c
Wings enable maple fruits to be easily carried by the wind.
(a)
Seeds within berries and other edible fruits are often dispersed in animal feces.
(b)
The barbs of cockleburs facilitate seed dispersal by allowing the fruits to “hitchhike” on animals.
(c)
Pollination
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
2 groups of Angiosperms (flowers) Monocots: 1 embryonic seed leaf called cotyledon
(lilies, palms, grasses, grain crops); parallel venation; 3 petals
Eudicots (formerly Dicots): 2 embryonic seed leaves (roses, peas, sunflowers, oaks, maples); netlike venation; 4-5 petals
Vascular tissue refinement: vessel elements/fiber cells