Name(s)_____________________________ _____________________________ Period________ Due Date__________

Barracuda Bellyache

ObjectiveThe student will be able to create a food web for a top-level carnivore (barracuda) in an aquatic ecosystem. The student will be able to show the flow of energy and label organisms within a food web with the appropriate vocabulary.The student will be able to show the flow of ciguatera toxin through a typical barracuda food chain.

VocabularyBenthic paralysisBiological magnification predatorCiguatera temperature-stabledinoflagellate trophic levelfood web latitude

MaterialsThis handoutComputer with microphoneInternet

BackgroundCiguatera poisoning in humans causes abdominal cramps, nausesa, vomiting, and diarrhea. It may also include numbness and tingling of the lips, tongue and throat. Some victims also suffer from dizziness, malaise, dry mouth, muscle and joint pain, blurred vision, rash, and reversal of hot and cold sensations. In rare instances, death may occur as the result of respiratory paralysis.

This seafood poisoning is caused by eating fish caught near coral reefs between 35° N and 35° S latitude. Fish most often associated with the poisoning are barracuda, red snapper, amberjack, surgeonfish, sea bass, and grouper although over 400 different species of fishes and shellfish have been implicated. The toxin is temperature-stable, so neither cooking nor freezing the fish will destroy it. Its presence cannot be detected by inspection, taste, or smell. IN the U.S. and its territories, ciguatera is the most frequently reported food-born disease associated with a naturally occurring toxin.

Ciguatera toxins originate from single-celled microscopic dinoflagellates. The most common species is Gambierdiscus toxicus. The benthic algae is sporadically distributed in the tropical waters of the Atlantic and Pacific Oceans. It is usually found in sheltered areas with little wave action or freshwater inflow. It is generally attached to larger algae, coral reefs, and other hard substances. Many ciguatera poisoning outbreaks are associated with events that disturb the bottom, such as dredging, anchoring, and severe storms.

Dinoflagellates, like ciguatera-producing G. toxicus, are food for many small marine fishes and invertebrates. The animals are in turn fed upon by larger ones. In this way, the ciguatera toxin enters the food web. As animals at each higher trophic level feed, the toxin amounts become magnified. Barracuda are top predators and consequently frequently contain toxin levels that are high enough to make human consumption dangerous.

Procedure1. Research the barracuda’s food web on the

internet. Find a picture of a barracuda and pictures of things typically eaten by barracuda. (be sure all pictures are labeled)

2. Find pictures of things each of the above fishes would eat. (label each)

3. Continue the process all the way down to dinoflagellates, which as producers make their own food. Include both poisonous and non-poisonous species of dinoflagellates.

4. Construct a food web using your pictures w/ labels. Arrange the pictures in trophic levels. Draw arrows from the organisms being eaten to the organism(s) that eat it. Label all trophic levels, the amount of energy available in each level, and types of autotrophs or heterotrophs.

5. Using your food web, illustrate the concept of biological magnification as explained by your teacher. Use dots to follow the path of the toxin upward from the poisonous dinoflagellates. Use one dot to indicate one dose of toxin. Each organism that eats an organism containing toxin gets all of the doses (dots) of that organism

6. Using “screencast-o-matic.com” your group will record your explanation of the food web, energy flow, and biological magnification. The file will be saved on a flash drive and given to Mr. Adams to upload on his computer.

7. Your grade for this project will be calculated using the following rubric. Your final product will be a food web diagram and an oral presentation by your group of the biological magnification & energy flow concepts within a food web.

Grading rubric Possible Points Points Earned

Food web with at least 12 different organism pictures & labels 20 pts _____All vocabulary correctly defined 10 pts _____Trophic levels labeled and types of autotrophs/ heterotrophs identified 10 pts _____Arrows drawn correctly 5 pts _____All feeding relationships correct 10 pts _____

Biological magnification and energy flow

explained correctly in oral presentation 25 pts _____Amount of energy found at each trophic level 10 pts _____Both partners giving presentation 10 pts _____

Total 100 pts _____

Comments:

Online tools for creating your project include (but are not limited to): Powerpoint, Prezi.com, piktochart.com, create.visual.ly, infogr.am, google charts, word, glogster.com, movie maker, screencast-o-matic.com, etc.