Name(s)_____________________________ _____________________________ Period________ Due Date__________
Barracuda Bellyache
Objective
The student will be able to create a food web for a toplevel 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.
Vocabulary
Benthic
Biological magnification
Ciguatera
dinoflagellate
food web
paralysis
predator
temperature-stable
trophic level
latitude
Materials
This handout
Computer with microphone
Internet
Background
Ciguatera 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.
Procedure
1. 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 nonpoisonous 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.
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.
Grading rubric
Food web with at least 12 different organism pictures & labels
Possible Points
20 pts
Points Earned
_____
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
_____
100 pts
_____
Total
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