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Learning Goal 5:
Understand how POLLINATION and SEED
DISPERSAL are ADAPTATIONS that
allows for plant SURVIVAL, including:
• How it works/happens
• How other organisms may
SYMBIOTICALLY assist
What main survival need do POLLINATION
& SEED DISPERSAL meet?
How It Happens• Pollen falls from the anther (male – sperm) to
the stigma (female – leads to ovary/egg)
• Sperm cell (pollen) joins the egg cell in the ovary
• This fertilization process results in a seed (zygote)
• The fruit forms around the seed-hopefully making the seed more attractive for dispersal
What is pollination?
• Self-pollination: transfer of pollen from anther to stigma of same plant
• Cross-pollination - transfer of pollen to a different plant (of the same species)
Pollinating animals visit flowers not because they are pretty or smell nice, but because they offer sugary
nectar and protein rich pollen.
Flowers “trade” their food in hopes insects will be attracted and pollinate.
Bees
Both honeybees and native wild bees such as bumblebees are attracted to flowers with bright lively colors especially blues and yellows. Bees cannot see red. Notice the “landing pad”?
Bats
Bats typically pollinate at night in the areas such as American Southwest and the rainforest. Flowers pollinated by bats are typically large and sturdy. Night blooming flowers are the most common flowers pollinated by bats such as cactus flowers (saguaro)
ButterfliesBlossoms built for butterflies have lively colors, especially pinks, blues, and yellows. They are often grouped together in small masses.
The floral tube is usually narrow, restricted to allow for the butterfly’s slender tongue… fat bees keep away!
BIrds
Red is a banner that says “EAT HERE” to these fast flying birds (hummingbirds). These pink, orange, and red blossoms are narrowly constricted so that only narrow bills can enter. There is no landing platform on the flowers.
Gymnosperm• Seed is not enclosed
(ex: pinecone)
• “Non-flowering” seed plant
• Tree or plant usually has needles that stay green year round (pine trees, firs, cedars and spruces)
How are pine needles a good adaptation for survival in cold climates?
Pollination of Gymnosperm
• Pollination occurs once a genetically compatible pollen grain lands directly on the “naked” ovule.
• It may be ONE YEAR or longer between pollination and fertilization!
• Once fertilized, the seed is released and grows into a new plant or tree
Seed Dispersal
Seeds need to reach a destination where they can grow.
• How do they get there without a way to cause movement of their own?
• How do they not compete with the parent plant?
Birds• Birds can carry seeds to a
new location in their
mouths or the seeds may
be dispersed when the bird
poops!