"In preparation for a life cycle unit, I took my second graders to a local farmer's market with the intent of finding seeds on the way and hidden in the produce we brought back," reports Marilyn VanDerWerff from Fremont, MI. Back in the classroom, Marilyn's students counted, sketched, compared, and wrote about the treasures they'd discovered.
"The students tried growing some of their found seeds under different conditions, but had mixed luck with germination," says Marilyn. "We then focused on experimenting with the Fast Plants seeds that a parent had obtained for us." (See sidebar, right.) After all, those miniature plants will reliably go through a complete life cycle in just six weeks. Working in small groups, the youngsters tested some of their ideas about plant needs, such as how different amounts of fertilizer might affect growth. "As the students measured, drew, and described in their lab books what they saw, they were amazed at how quickly the plants began to bloom -- in just a few weeks," she explains.
In response to the students' flower focus, Marilyn invited them to share what they knew about these vital plant parts. "The idea that bees often visit flowers inspired a discussion about what the creatures might be looking for," says Marilyn. "Some kids knew a bit about bees looking for pollen, but didn't seem to have a sense of what the plant might get out of the deal," she adds. The Fast Plants kit provided a tool for finding out: dried bees. With guidance, students used toothpicks to make "bee sticks," then tried their hands at doing what hungry bees do. "The students took their mission seriously and developed theories about what would happen in the process," says Marilyn. She explains that, based on previous observations, students knew that a single bee travels to many flowers. As her keen observers buzzed around the room working the flowers, they noticed the yellow pollen that seemed to get stuck on the bees. This inspired a close-up look at bees through hand lenses. "This is soooo cool" was a familiar refrain as students discovered the bristly bee body hairs and sac-like indentations on the legs.
Only a week and a half after playing pollinators, Marilyn's students began to notice pods forming as the flowers withered. Soon after, when the pods and plants began drying, students harvested them and discovered the seeds inside. "They were delighted to find the seeds and began to make the connection to the bee activity," says Marilyn. "The real 'aha' may have come as they noticed that none had formed on the flowers that had not been visited by bees," she adds.
Bees pollinate more flowers than any other creatures on earth. There are many different types and sizes of native bees that do so, but honeybees, which originated in Europe, deserve special mention. They are the only insect we rely on for food (honey) and pollination of many of our commercial food crops.
In honeybee society, it is the worker bee "scouts" who scope out an area for signs of flowers rich with pollen and nectar. They then spread the word back at the hive by "dancing" a message for other bees. The speed of the dance and numbers of "waggles" performed tells the other worker bees the distance and direction to the food source.
There's no hanging around the dance floor for worker bees. They are off to the site to forage for nectar and pollen, and they quickly become attuned to the colors, shapes, and smells of particular flowers. In fact, on any given trip, a bee typically gathers nectar from only one kind of flower. It draws it in through a tube that contains its 1/4-inch tongue, consumes some on the spot for energy, then brings the rest to the hive to make honey and nourish the young. Worker bees also use their front legs to gather protein- and vitamin-rich pollen, then push it back to sac-like indentations on their bristly back legs. Their abdomens also have bristly hairs that hang on to pollen as they brush against flower anthers. (As students observe bees at work, they may notice that some are pollen-laden, like a dustmop that needs to be shaken!) As they visit other flowers, the bees inadvertently leave some behind, paving the way for pollination and fertilization.
Sunny, warm, and calm weather means business to a worker bee, but extended rainy periods, which decrease nectar production, can dampen their inclination to forage. If your students notice that squash or cucumbers aren't producing much fruit, ask them to consider what environmental factors might be responsible.