At CASE, teachers
experience science as we hope their students will ...
After a period of discovery, during which participants search for the stamens, examine the pollen under a microscope, and search for the female flower parts, a discussion of flower shape and adaptation ensues.
Pollinators are considered. What does the size and shape of the different flowers indicate about the different insects and birds that pollinate them? How does the blooming pattern help the plant's chances of being successfully pollinated? Where do the seeds form?
This
45-minute warm-up introduces many valuable concepts-adaptation, co-evolution
of insects and plant and seed production. The activity identifies misconceptions
some of the teachers have. For example, prior to the lesson, some teachers
have
the misconception that pollination is required for a plant to flower.
The large number of different flowers gave the participants the opportunity
to examine and compare a range of flower types and forms. This is an activity
that can easily be replicated in the classroom where students can explore
the form and function of flowering plants.
After the warm-up, the teachers engage in activities designed to answer two investigative questions: what variations exist within plants and animals of a given environment? and How do the life cycles of plants and animals compare? In one classroom participants are given two bowls; one contains about 20 different types of seeds (representing an environment of limited biological diversity) and the other over 60 different kinds (representing an environment of rich diversity). The groups are asked to sort the seeds and describe the diversity they observe. They identify differences in size, weight, shape, color, and thickness of coat and cotyledon of the seeds. The teachers are expected to realize that the diversity among the seeds reflects the diversity of the plants from which they come. At this point the class is asked, "How does each seed know what plant to become?"This is a fundamental question for the elementary level.
A
discussion of variation and genetic origins begins, drawing out what individuals
in the class know. The instructor asks, "How does variation within
a species help or hurt that species survive?" To investigate the
question the class plays a game. Each group is given a box with cardboard
moths that vary in color from white to various grays to black; the bottom
of the box is an irregular black and white splotchy pattern. Participants
are instructed to "randomly" pick out five moths from the box
and record the results. The moths are returned to the box, mixed and the
game continues until all participants have drawn three times. The results
are then tabulated by class and at the end of the day 300 draws are represented.
The results astonish the teachers. The lighter colored moths are frequently selected; the darker colored moths are harder to see against the dark background of the box. These experiences elicit discussion during the week on Life and Environments that develop important concepts on human genetics, adaptation, mutations, inherited characteristics, and the patterns of living organisms.