Slide 1
The angiosperms - otherwise known as the flowering plants - are the dominant plant group on earth today with approximately 275,000 known species.
The flower is the reproductive structure of the plant that is derived from modified leaves and plays an important role in pollination.
The seeds of the angiosperms are considered "housed" seeds because the seed is complete enclosed within an ovary - which is the fruit.
The fruit and flowers are responsible for the success of this group.
Slide 2
The flower contains either male reproductive structures, female reproductive structures, or both.
The
male part of the flower is known as the stamen and it is comprised of the
anther and the filament. The anther produces the pollen.
The
female part of the plant is known as the carpel and is made up of the stigma,
style, and ovary. The ovary houses the egg which will become fertilized
to produce the zygote. After fertilization, the ovary will develop into
the fruit and house the seeds.
The petals of the flower typically are colorful and attract animal pollinators.
Slide 3
The flowers are the reproductive structure of the angiosperms and they can be classified as either perfect - which means they have both male and female parts on the same flower or imperfect - which means the flower has either male or female parts but not both.
Many species of angiosperm take advantage of animals for pollination and seed dispersal (including humans)
This ability to take advantage of animals is what has made the angiosperms so succesful.
Slide
4
When pollen lands on the stigma it grows a pollen tube into an ovule where it deposits two sperm nuclei - this is a process known as double fertilization.
Slide 5
Pollination is the process of moving pollen from one plant to another and, in the angiosperms, it often involves an animal pollinator.
Slide 6
Not all angiosperms take advantage of
animal pollinators. Some use the wind for pollination.
Characteristics
of wind pollinated plants include that they produce large amounts of pollen,
and small inconspicuous flowers.
Pollen travels <100 meters so wind pollinated plants must grow close together
Trees (oaks) and grasses are often wind pollinated.
Slide 7
Wind pollination is a wasteful process - if the wind blows the wrong way - all that pollen and all that reproductive effort is wasted.
Slide 8
Animal
pollinated plants produce smaller amounts of pollen.
Instead of putting energy into abundant pollen production they put their energy into producing large, showy flowers - these flowers attract pollinators, often give a them a reward - such as nectar.
Pollinators can carry pollen large distances so animal pollinated plants can be widely separated.
Slide 9
All
kinds of animals can be pollinators - insects, birds and even mammals.
The features of the flower fit the pollinator. Insects tend to be attracted to yellow flowers with flat surfaces for landing. Birds are attracted to red and hummingbirds hover in front of the flower and don't need to land.
Bats are active at night so bat-pollinated plants are typically white and highly scented.
Some plants even attract beetles and flies as pollinators - this flower is the color of meat and has the pungent odor of rotting flesh - beetles anf flies love it!
Slide 10
Some plants take advantage of animals but do not give them a reward. Orchids in the genus Ophrys are wasp and bee mimics. They produce pheromones that mimic the pheromones of a female and they even look like a female.
Male wasps come and attempt to copulate with the flower. In the process they pick up pollen and then deliver it to another flower.
They do not get any nectar or other food.
These orchids are parasites. They essentially steal reproductive energy from the wasps.