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Melittobia digitat & Brassica rapa:
Cornell University Comes to Marcus Whitman!

Marcus Whitman Central School District Newsletter. April 2002.

What’s a great way for kids to learn biological concepts, using a hands-on approach? How about growing some plants and insects??!!

Since the beginning of classes in September, Rebecca Smyth, an entomologist from Cornell University’s school of Agriculture & Life Sciences, has been visiting Pete Saracino’s 7th and 8th grade Biology classes. Ms. Smyth is a PhD. candidate and a Fellow with the Cornell Environmental Inquiry Research Partnership (CEIRP). The Partnership provides support for teachers and students conducting original research or inquiry-based projects in the environmental sciences. Cornell undergraduate and graduate Fellows guide classroom projects using Environmental-Inquiry curricula as well as activities the fellows develop based on their own research expertise.

Each Friday since early September has been “Cornell Day” in Mr. Saracino’s Biology classes. Relying on Rebecca’s expertise, Mr. Saracino’s classes have been engaged in two different studies. One study involves “raising” parasitic wasps, scientific name: Melittobia digitata. Don’t worry. These wasps aren’t much larger than a flea. And they don’t sting! The other involves raising mustard plants, scientific name: brassica rapa.

So, why on Earth would anyone want to raise wasps??!!!

The answer’s easy! What better way to explore a good number of Life Science concepts than to “raise a little life”!! Principles like life cycles (each student raised the wasps from adult to egg to larva to pupa and back to adult), metamorphosis (students were able to see each life-stage first-hand), symbiosis (adult female wasps are parasitic on mud daubers; they lay their eggs on mud dauber pupae; once hatched, the larvae use the pupae as a source of nourishment), reproduction (students used bioassays to study how the female wasps find a sexual partner using chemical cues called pheromones), parthenogenesis (if the female wasp cannot find a male to mate with, she simply lays more eggs; the eggs that hatch are all males, and she mates with her own offspring!) come easily to life as the kids see the action taking place before their very eyes. And students had their own batch of wasps to observe and study! Another bonus of this project was the skill gained by the students in using a dissecting microscope. These wasps are very small, and the kids were often required to observe the “action” under these microscopes. In the end, they became quite proficient at operating these scopes. Last, but not least, the students were required to keep a lab manual where daily observations were recorded and drawings made. This gave them practice doing science just like real scientists do!.

Now, on to mustards! What can be learned from this humble plant? The answer is natural selection and genetics! What better way for kids to learn about these concepts than by growing plants, observing their traits, then choosing (or “selecting”) which traits they want to try to pass along to potential offspring?

Under Rebecca’s guidance that’s exactly what the kids did. They grew the mustard plants from seeds. Care was taken to ensure that each plant was given the same conditions of light, temperature, fertilizer, and moisture. As the plants grew, students made careful observations - complete with drawings – of each phase of the plant’s life – just like real scientists.

Why such meticulous care and observation? The goal of this phase of the project was to determine if certain traits were “heritable”. That is, would a tall plant be able to pass along its trait for “tallness” to its offspring? Or, was a plant’s height determined only by the conditions in which it grew? Or, perhaps the trait reflected a combination of both heredity and environment!

The two traits chosen were “height” and degree of “stem hairiness”. These traits were measured on each plant. Then, pipe cleaners in hand, the students pollinated flowers. Tall plants were crossed with tall plants; short were crossed with short; hairy were crossed with hairy; smooth were crossed with smooth.

And then, they waited.

The plants were allowed to go to seed. These seeds were then harvested and used by the kids to grow the next generation of plants. When the new generation had grown to their full stature, new measurements were taken, results tabulated, and conclusions drawn.

Much was learned! By growing, observing, drawing, pollinating, harvesting and replanting real-life plants, the kids received first-hand knowledge about plant and flower parts, plant pollination and reproduction, seed harvesting and replanting, genetics and natural selection.

In closing, both projects provided Whitman students with an avenue to learn a broad range of biological concepts. A more subtle benefit to the kids was the opportunity to work with a real-life scientist – and a female one at that! Ms. Smyth provided the students with an excellent role model for young people – especially the young girls - who aspire to pursue a career in the sciences.

The projects were a great success. Mr. Saracino feels that they were so beneficial he has decided to have a Cornell fellow join his classes each fall to help Whitman students explore the world of science.

Click here to see photos.