Teacher Support/Lesson PlanObjectives: The students will be able to identify the organisms that rely on either Oysters or Zebra mussels for their habitat.
The students will be able to identify organisms based on the trace evidence left on the shell of a bivalve.
Note: Pictures of organisms which settle on oysters may be seen at Maryland Sea Grants web site/ page Oyster Anatomy: http://www.mdsg.umd.edu/oysters/anatlab/lab.htm
The students will be able to graphically represent, compare, and contrast the communities that would be associated with Oyster bars, or colonies of Zebra Mussels.
The students will be able to explain the effects that zebra mussels are likely to have on the ecosystem, water quality, and oxygenation of the Chesapeake Bay as well as measures that could be taken to discourage the presence of the Zebra Mussel.
Outcome addressed;
Prince George's County; Explains the impact of natural forces and human activities on the environment.
National Content Standards; The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem.
Time Required: Approximately 3 one hour periods, but you know your kids better than I do.
Materials needed (per lab group):
Uncleaned Oyster shells, Uncleaned Zebra Mussel shell, hand lenses, graph paper. That's it.
A little advice:
Finding the Oyster shells should be fairly simple. Any place that sells Oyster's on the half shell should be able and willing to give you all you want for free although they may smell a bit like cocktail sauce. Zebra Mussels, however may be a bit more difficult to acquire. Check with the Maryland Department of Natural Resources, or their local equivalent for populations that are accessible. The city of Baltimore has taken proactive measures to prevent infestation by the Zebra Mussel. Their example might be helpful to the students attempting to determine how to prevent Zebra Mussel infestation.
The traces that you are likely to encounter on Oyster shells are not particularly diverse, but there are more than you find on a Zebra Mussel. Oysters are often home to barnacles. If the barnacle has broken free, there will be a circular scar, with lines running from the center to the edge. Oyster spat that fall off generally leave an irregular, circular smooth patch. Bryzoan colonies appear as a dark grid. Mussels sometimes leave a collection of fine threads where they were anchored to the oyster. The only thing you normally find on Zebra Mussels are baby Zebra Mussels.
A few additional activities that might be useful as alternatives to what is presented here are available, for those of you who would like an alternative.
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