Food webs and trophic dynamics are important biological topics that explain community interactions, ecosystem energetics, and other ecological phenomena. Interactions among organisms in different trophic levels is a particularly important factor shaping the structure and function of communities and ecosystems. To investigate the interactions between producers and consumers, you will construct a simple ecosystem containing an algal producer and a crustacean herbivore and observe what happens over the course of a two-week period in this simple food chain. In this experiment, you will use an experimental design developed by Hudon and Finnerty (2013), but in a “flipped” format. You should first view the assigned videos that describe the fundamental features of the experimental procedure. Make notes about experimental design to investigate bottom-up or top-down effects in a simple ecosystem composed of a single producer and consumer species.
The producer is a unicellular, marine alga in the genus (Platymonas sp.). This species has a flagellum which allows it to swim through its aquatic environment. The consumer is Artemia salina (brine shrimp), a crustacean related to crabs and lobsters. They hatch from cysts and are easily grown in lab. The larva, called a naupilus, are active swimmers and develop into the mature adult form in a few days. The mature adults are grazers that feed on algae.
Hudon, D. and J.R. Finnerty. 2013. To build an ecosystem: an introductory lab for environmental science and biology students. The American Biology Teacher 75:186-192.
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