Insects and Flowers: The Biology of a Partnership (Friedrich Barth)
season appear to be the most important variables influencing insect visitation rates. Results of this study indicate that relationships between insects and flowers . Evidence from the fossil record and from the inferred ecological and phylogenetic relationships between flowering plants (angiosperms) and their insect. Plant evolution before their relationship with insects was limited by the ability of insects to collect in exchange for visiting the flower and picking up the cargo.An Orchid’s Trap - Wings of Life
Most feed on the nectar of a flower. The nectaries are usually located deep in the middle of a flower so that pollinators have to first brush against the anthers, and then the stigma to get to the nectar. Some pollinators, like bees, need pollen in addition to nectar. Some pollinating insects e. The insects try to leave quickly but the flowers may have traps to slow the insects down.
It may be useful to ask a few students to role-play the pollination process. Part One Assign each group a pollinator: They can pick a name out of a hat or you can assign them. Pass out the Pollinator Observation Data Sheets 1 per student. Students should take time to read the descriptions of all the flowers and look at the data before answering the questions. On the back, they will answer the following questions: Who is your pollinator?
What number flower did your pollinator visit the most? What are 3 flower traits that you think attract your pollinator? Let students know that they are beginning to construct explanations about what flower features attract their pollinator. Their explanations right now are only based on observations in the field, which is exactly how research scientists build their explanations.
In the next step, they will receive more information about their pollinator to modify or strength their explanations. Each group should get the Pollinator Profile that corresponds to their pollinator. Once students have read their Pollinator Profile, they will write down 3 flower traits that are attractive to their pollinator on the Constructing Explanations sheet.
This time, they will have more information to use, so remind students to consider the following: Compare the information in the profile to the data gathered from pollinator observations. Encourage students to not just look at the data from the flower their pollinator visited the most, but look at trends amongst all the flowers.
For example, bees went to Flower 2 the most, but they also went to Flower 6 — do Flowers 2 and 6 have anything in common? These may end up being the same 3 traits that they wrote down earlier, but they need to be supported by the information they just learned about their pollinator. Part Three Set up your Imaginary Garden.
Insects and Flowers - The Pollinator Garden
Set up your garden while students are working on Part Two, or do Parts One and Two before recess, and set up your garden while students are outside. Use a large table or area on the ground so the flowers may be spread out. Have the students come gather around the garden.
Tell them that their job is to find one flower that that their pollinator would be most attracted to, based on their observation data and the information in their Pollinator Profile.
It is important that they look not only at the flower itself, but the unobservable traits smell, when it blooms, etc. Remind students that in nature, flowers do not have tags explaining when they bloom or what they smell like. Botanists would have to go study the flowers, sometimes at night. Each group should work together to select one flower that their pollinator would be attracted to. Once they have selected their flower, they will take it back to their table.
On their Constructing Explanations sheet, they will circle which flower they chose and write one sentence describing why that flower would attract their pollinator. Wrap-Up Have students present their flowers to the class and explain why it would be attractive to their pollinator.
Highlight that these evolutionary changes do not happen overnight. It takes hundreds or thousands of years for these adaptations to take shape.
Pollinator - Wikipedia
Ask students what they think would happen to their flower if their pollinator disappeared. If it did, how would it change? As a final discussion question, ask students how the pollinators may be adapted to the flowers. This can also be turned into a larger lesson or homework assignment, if desired see Extensions. Extensions You may choose to extend this lesson and delve more deeply into flower anatomy at the beginning with a more formalized flower dissection.
Take a field trip to a flower garden. Record your observations on what pollinators you see there. Be sure to include notes about the flowers themselves.
Did you find anything surprising? To add an arts aspect, have each student create a flower with craft materials that would be attractive to their pollinator. This works especially well as an extension if the Imaginary Garden cards were used. Have each student write a few sentences about why this flower attracts their pollinator, and create a pollinator bouquet with the whole class.
If students are advanced, you can extend the lesson through an exploration of co-evolution. Challenge students to research pollinators and find out the ways in which the pollinators themselves are adapted to certain flowers.
You can read more about it here. Educator Background The Angiosperm Lifecycle For angiosperms, or flowering plants, to reproduce, they go through pollination, create fruits, and disperse seeds. For the students, it is useful to describe the process in four steps: In some cases, plants do not need animals for pollination or seed dispersal. In other cases, plants rely on animals for both processes and must attract each animal in a different way.
Pollination is the transfer of pollen from the stamens to the stigma of flowers.
Friedrich G. Barth
Pollen can be carried by insects, other animals, wind, or water. Self-pollination refers to the process in which pollen lands on the stigma of its own flower or another flower on the same plant. Cross-pollination refers to the process where pollen is transferred to the stigma of a flower on another plant of the same species. Since ovules within the same plant can differ genetically from one another, self-pollination can result in some variation in the offspring.
Cross-pollination, in which genetic material comes from two parents, results in greater variation and is therefore considered advantageous.
- Bugs and Flowers
Once the pollen grain reaches a compatible stigma, it receives a chemical signal from the stigma. The pollen then produces a tube, which grows down through the style, into the ovary, and into one of the ovules.
This allows the male pollen cell to fuse with the female cell inside the ovule. While most evolutionary processes involve direct adaptations of a single species, with bees and flowers, the evolutionary process involves two interlinked species.
Wind has the advantage of carrying pollen long distances and spreading it over vast areas. However, in wind pollination, much of the pollen will never find its way to the proper species of plant. Insect pollination helps solve this problem. Therefore, those plants most able to attract insects were also those most likely to survive. Thus, plants evolved certain characteristics to attract insects such as bees. Because bees in particular may collect either nectar or pollen for food, they have become among the most efficient of pollinators.
As flower pollinators, bees have evolved into a powerful connecting force in Nature. Take a moment to think about how you are connected to and dependent upon the connection between bugs and flowers. Either directly or indirectly, much of your food comes from pollinated plants. Consequently, you are part of the larger series of interrelationships that depend upon the biological intimacy between bugs and flowers.
Worth Your Extra Attention: The University of Cincinnati has provided an excellent web page with lots of detail about coevolution. It is worth your time to examine their wide assortment of fascinating examples of coevolving connections in Nature.
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