Bringing Scientific Inquiry Alive Using Real Grass Shrimp Research

Article excerpt

When scientists seek answers to questions or explanations behind events or observations, they use processes that encourage logical thought, careful planning, thorough research, and detailed experimental design. These processes are not always based on a standard formula of steps, but do typically include the following skills:

* Observing and being curious about the environment

* Coming up with an idea/identifying a problem or question to study

* Collecting background material

* Formulating a testable hypothesis

* Designing a study or experiment that will directly address the hypothesis and control variables where appropriate

* Performing the study and collecting the data

* Analyzing the data

* Proposing explanations and drawing conclusions

* Presenting the findings

Students often struggle to master these skills, especially in formulating a testable hypothesis and limiting conclusions to the actual experimental results. Although science teachers strive to provide meaningful examples of scientific inquiry throughout the school year, time constraints and the need to cover an extensive curriculum often restrict activities on the nature of scientific inquiry to the start of the school year.

This lesson was developed for middle school students using actual research on grass shrimp (Palaemonetes pugio) to illustrate the process of a scientific investigation. The research was conducted at Savannah State University and funded by the National Oceanic and Atmospheric Administration (NOAA) Office of Education through the Living Marine Resources Cooperative Science Center. The lesson has wide applicability and could be used as training on the processes of scientific inquiry, as part of the life science curriculum on crustaceans, or as part of an Earth science/environmental science curriculum. The lesson is a simulation activity and not an actual hands-on investigation; it could be effective in introducing inquiry skills. Although the focus of this activity is on the prevalence of a parasite on an estuarine organism, the framework could be modified to be more applicable to other environments by considering proportions as they relate to the number of four-leaf clovers on a playground, the number of weeds in a small patch of grass, a comparison of the number of large versus small insects around a porch light, or the number of a certain color of candy in a package (Curran 2003).

FIGURE 1 Background information sheet: Grass shrimp

There are many species of grass shrimp, which are animals
in the phylum Arthropoda and subphylum Crustacea.
Grass shrimp are abundant in most estuaries of
the eastern United States and the Gulf of Mexico (Anderson
1985; Gosner 1978). Grass shrimp can survive
in water that ranges from freshwater to a mixture of
fresh and salt water (brackish), to full-strength seawater,
and they can survive a wide range in water temperature
(Anderson 1985). Grass shrimp are abundant in
shallow water that is cloudy with suspended sediment
(Anderson 1985; Ruiz, Hines, and Posey 1993). They
also live in areas with submerged underwater vegetation
and marsh grass (Anderson 1985). If the amount
of marsh grass or vegetation in an estuary is reduced,
the number of grass shrimp normally present may decrease
(Anderson 1985). When docks and roads are
built, or when wetland areas are filled in with dirt, the
area with marsh grass will get smaller. This reduces
the habitat for the grass shrimp.

Grass shrimp are sensitive to conditions in their
environment. Grass shrimp are known as an "indicator
species." Changes in the grass shrimp population
structure can indicate whether there is a change in their
ecosystem (Key, Wirth, and Fulton 2006). For example,
it has been found that if an estuary receives a high
concentration of polluted water runoff from roads and
highways, the grass shrimp may experience reduced
production of embryos and reduced rates of hatching
(Lee, Maruya, and Bulski 2004). …