Pollination - The Story Behind Bees and Flowers
Lesson 2 of 2
Objective: SWBAT to develop and argument to explain how bees influence the probability of successful plant reproduction.
To engage students in lesson I show students the TEDEd video Nature's Matchmakers on how bees help plants have "sex" (attention-getting word - could use reproduce if you'd rather but the word sex is used in the video).
Teacher Note: This video introduces students to new vocabulary in addition to new concepts. It's crucial that you stop video in the following minutes to scaffold content:
- Minute 1:25 (Figure that explains number of plant species vs pollinator species)
- Minute 1:51 (Evolution of bees from wasps)
- Minute 2:00 (Pollinator Networks)
- Minute 2:20 (Specialists)
- Minute 2:30 (Generalists)
- Minute 3:00 (Nested Network)
- Minute 3:45 (Modular Network)
Students are required to answer the questions below as they watch video:
1. Most pollinator networks for which we have data are “nested.” Draw and describe how a nested plant-pollinator network looks like. Which may be the reason for nestedness to evolve?
2. In addition to nestedness, the networks are usually “modular.” What a modular structure means and which is the advantage of a modular structure?
3. Today, around ________ plant species receive pollination services from more than 200,000 pollinator species.
4. How much of our food production depends on bees?
5. Fossil records suggest bees may have evolved from ________ that gave up hunting after they acquired a taste for nectar.
6. Plant-pollinator networks are everywhere. Ecologists record these networks in the field by observing which pollinators visit which plants, or by analyzing ________.
a. The gut content of pollinators
b. The fingerprints left by pollinators when the visit plants
c. The DNA left by pollinators when they visit plants
d. The identity of pollen loads on the body of pollinators
7. The main characteristic of the architecture of all plant-pollinator networks on Earth is ________.
a. All species have similar number of interactions
b. Most species have few interactions and few species have many interactions
c. Most species have many interactions and few species have few interactions
d. There is not a common characteristic, all networks are different.
In this section of lesson students explore pollination by completing a simulation of bee pollination. (SP2 - Developing and Using Models)
2. Give each student a photocopy of Bee Diagram. Have them study the line drawing of the bee. Ask them to identify and write down the bee structure or structures that do the following:
3. Divide the students into two groups: the pollinators (bees) and the plants. Give each member of the plant group a cotton swab and a small amount of "pollen" (talcum or other type of powder) in a container or dish. Instruct each member of the pollinator group to visit a member of the plant group and dip a finger into the pollen. At this point, ask the class to name the part of the plant that the pollinators touched (the stamen, which consists of the anther and the filament) to get the pollen on their fingers. Have them determine whether it is a male or female part. Ask the students what parts of the pollinators' "bodies" (represented by their finger) touched the stamen that could carry the pollen to the next plant. Ask what they were looking for when they got to the plant (nectar) and what appendage they used to get it (proboscis bristles).
In this section of lesson I show students a clip from the movie Wings of Life from Disneynature. At the time that I'm writing this lesson the entire movie is being streamed on Netflix.
The objective of showing this clip is to show students in real life how the behaviors of different pollinators influence the reproductive success of different plant species. This clip summarizes what students have learned in the previous two sections of lesson. You might want to pause it at key points and ask students what they've noticed.
To elaborate on what students have learned in the previous sections of lesson I show students the video below that discusses an escalating problem in the world that scientists are frantically trying to find a solution to.
In the past decade, the US honeybee population has been decreasing at an alarming and unprecedented rate. While this is obviously bad news for honeypots everywhere, bees also help feed us in a bigger way -- by pollinating our nation's crops.
As students watch video I have students answer the following questions:
1. In affected colonies ________________.
a. There is no queen bee
b. The food stores remain untouched
c. There are dead bees everywhere
d. The comb has disintegrated
2. Colony collapse disorder will only affect the price of honey.
3. When was colony collapse disorder found to affect over half the commercial hives in the United States?
4. Since when have humans domesticated bees?
a. 200 years ago
b. The early 1900's
d. The 1600s
5. Honeybees generate over one third of food in the United States by pollinating crops.
6. Are there particularly important crops that you think should be protected especially from the effects of colony collapse disorder?
In this section of the lesson, students match pollinators with the plants they pollinate. Besides the figure below I have included a printable version of the activity. This activity is courtesy of NOVA.
After you print this page out, match the pollinators shown above with the plants they pollinate (below). Note there is only one correct choice for each plant. Write your answers in the space provided.
To wrap up the lesson, students complete an Exit Slip where students are required to develop an evidence-based argument on how pollinators impact the reproductive success of plants. (SP7 - Engaging in Argument from Evidence/MS-LS1-4 - Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants respectively/CCC - Cause and Effect.)