SimBio Virtual Labs®
EcoBeaker®: The Barnacle Zone
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SimBio Virtual Labs®: EcoBeaker® The Barnacle Zone
When we tell our kids about different species and where they live, we naturally start talking about weather ...view middle of the document...
You would expect, therefore, that organisms living in the upper intertidal zone would need very different adaptations than those living in the lower intertidal. In addition to including a range of physical environments, the intertidal zone is home to many different kinds of organisms who spend their time either stuck to the rocks or moving slowly around them. This makes it a great habitat in which to study how organisms interact with one another and whether or not those interactions shape organisms’ distributions.
This lab simulates life on the side of a rock along the rocky intertidal coast of Scotland. Our simulated rock is inhabited by two species of barnacles, small animals that, as adults, have shells that are shaped like little volcanoes. Although they don’t look like it in their adult stages, barnacles are crustaceans, related to crabs and lobsters. As adults, barnacle shells are cemented to a rock or other hard object, so that an adult barnacle can’t move anywhere. When a barnacle is submerged, it opens its shell and uses its feathery legs to filter the water for food particles. When the tide recedes and a barnacle is exposed to the air, it closes its shell tightly to keep itself from drying out. Although the adult barnacle can’t move, it makes larvae that can swim around in the water in search of appropriate places to settle and live out their adult lives.
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SimBio Virtual Labs® | The Barnacle Zone
Two common species of barnacle live on the Scottish coast; one is Semibalanus balanoides (formerly Balanus balanoides) and the other is Chthamalus montagui (formerly Chthamalus stellatus) When you walk along the shore, you can see that above a certain height, the rocks are covered by Chthamalus but have very few Semibalanus individuals. (Note: This lab refers to the two barnacle species by their Genera names.) Lower on the rock, the pattern is reversed, with Semibalanus abundant and Chthamalus rare. In the early 1960s, a researcher named Joseph Connell decided to investigate the cause of this pattern. He knew that one important determinant of where intertidal organisms live is how much they are exposed to air. Connell wanted to know whether exposure to air was the only condition that governed which species of barnacle lived where, or whether some interaction between the two species of barnacles also had something to do with it. In this lab, you’ll repeat some of Connell’s experiments.
Outline of This Lab
This lab takes you on a virtual field trip to the coast of Scotland. While exploring the marine life along the shore, you encounter the side of a large rock upon which you find Chthamalus and Semibalanus, the two types of barnacles described previously.
In this simulated system, the depth of the water covering the rock decreases each day when the tide goes out, exposing barnacles on the upper part of the rock to air. This exposure may be difficult for barnacles on the upper part of the rock to...