REPRODUCTIVE ORGANS OF TERRESTRIAL ANGIOSPERMS R. Perry MALIBU HIGH SCHOOL
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in terrestrial angiosperms. The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) or allow selfing (fusion of sperm and egg from the same flower). Flowers give rise to fruit and seeds. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to beautify their environment, but also as objects of romance, ritual, religion, medicine and as a source of food.
The reproductive organ of a terrestrial angiosperm is also know as
A FLOWER
MALE PART the STAMEN
FEMALE PART the PISTIL
pollen
stigma
anther filament
style ovary containing ovules
petals sepals pollen = sperm ovules = eggs
stem
MALE PART the STAMEN
FEMALE PART the PISTIL
male gametes produces pollen holds up anther
captures pollen holds up + growth of endostigma sperm produces ovules
female gamete attracts birds and bees
sperm + egg = new seed !
protect ovary holds flower up
SELF POLLINATION pollination
gravity
wind
fertilization
CROSS POLLINATION
wind
gravity pollination
birds bees
PLANT #1
PLANT #2
fertilization
WHICH IS BETTER FOR EVOLUTION THE SURVIVAL OF THE SPECIES? SELF FERTILIZATION: ONE PARENT - ONLY ONE SET OF GENES !
CROSS FERTILIZATION:
+
TWO PARENTS A MIXING OF TWO SETS OF GENES !
IMPERFECT
FL O W
COMPOSITE
ER S
PERFECT
?
PERFECT FLOWERS (bisexual) A perfect flower is a type of flower that has both pistillate (female) and staminate (male) parts. It does not require wind, insects or animals to pollinate.
IMPERFECT FLOWERS (unisexual) An imperfect flower does not have male and female parts in the same flower. Pollination requires the wind, insects, animals or other agents.
COMPOSITE FLOWERS Com`pos´i`tae (Bot.) A large family of plants, having their flowers arranged in dense heads of many small florets and their anthers united in a tube.
THE END