Snail Variations - Going Further

Assessment

1. Students’ data and graphs can be collected and graded.
2. Written protocols for trait measurements can be passed between groups so that students get practice and feedback on writing a scientific protocol. You may wish to do this before having each group graphically represent their data. This extension generates considerable discussion on the causes of experimental error and measurement inconsistencies. It also allows the full characterization of the population of snails on a wide range of traits.

Going Further

1. Snails may be “tagged” with spots of nail polish then released into one or more environments (for instance, a school yard versus a vacant lot). Choose your environments carefully such that those areas actually can support a number of snails (a parking lot is probably not the best choice). Students can make hypotheses about which snails with what combination of traits will survive better in which environments. Changes in the populations’ traits may be monitored over time and may be correlated with the students initial hypotheses. In this way, students can ask very open ended questions about natural selection in the real world with living organisms. In the end, students may discover more about habitat choice and survival than natural selection per se, still it is an incredibly rich and varied exercise that the students thoroughly enjoy.
2. As described previously, garden snails are escargot and are quite tasty if prepared properly. There are several steps to preparing your snails for the table:
   1. Feed your snails just cornmeal (3 tablespoons for a dozen snails) for approximately 4 days.
   2. Fast your snails in clean habitats with just wet towels for 2 more days.
   3. Just before cooking, rinse the snails in cool water from the tap.
   4. Plunge the snails into boiling water, shells and all. Boil uncovered for 2-3 minutes. A lot of foam will develop so watch carefully.
   5. Drain the snails and rinse with cold water. Using a toothpick, carefully pry each snail from its shell.
   6. The tightly coiled gall section of the snail that lies deepest in its shell should be cut off and discarded.
   7. The final cleaning step is to rinse the snails in water with a splash of vinegar until the water no longer turns cloudy.
   8. To cook the snails, boil 2 cups of snails in a broth made from 3 cups of beef broth, 1/2 cup white wine, 1 small chopped onion, 1 bay leaf, 1/2 teaspoon thyme, 1/2 teaspoon parsley, and salt and pepper to taste. Simmer for 1 hour.
   9. For the traditional preparation of escargot in garlic butter, melt 1 stick of butter (8 tablespoons) then add 1 1/2 teaspoons of chopped garlic, 1 tablespoon chopped green onion, and 2 tablespoons chopped fresh parsley. Puree the melted butter and seasonings in a food processor. Add salt and pepper to taste. Drizzle the garlic butter evenly over cooked escargot in an oven proof dish like a ramekin.
   10. Bake at 400 degrees for 7 –10 minutes.
3. Investigate trait variations in plants. Grow plants in the classroom and compare trits such as plant height, color, time to flower opening, hairiness, and more. See the Raising Plants project for more details.