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1.1.1 Modeling Krill Behavior:
How do brine shrimp react to physical stimuli?
In this Activity students will simulate aspects of the Antarctic ice
ecosystem, and see how simple life forms respond, modeling links between
environmental factors and biological responses. Although brine shrimp
are different from krill and silverfish, students should recognize the
parallels with the work done by the Palmer LTER team.
Objective
Students will conduct a controlled experiment with brine shrimp eggs
in order to draw conclusions about this organism's response to variations
in light levels and water temperature.
Materials (for each group of 3/4 students)
- aluminum foil
- balance
- bar magnet
- brine shrimp eggs from a local tropical fish store
- cover glass and slide
- glass rod
- graduated cylinder
- ice cubes
- light source
- medicine droppers
- microscope or hand lens
- petri dish
- plastic bag
- salt solution
- Activity 1.1.1 Student Worksheet
- Krill to Kill? Blackline Master #10
Please note: as we've suggested in previous Passport to Knowledge field
trips, if the materials for any Activity are beyond the resources ordinarily
available to you, consider enlisting a local high school science teacher,
for whom such simple items are more likely to be available.
Engage
Any organism must respond to changes in their environment in order to
get food, avoid predators, and successfully breed-in short, to survive.
In the Antarctic, the LTER group has confirmed that some of the most important
factors are as expected: the seasonal cooling and warming of the continent.
But their work in the last few years has also begun to show the precise
mechanisms by which the (relatively) hotter/colder cycle works, by affecting
the size of the ice-sheet, the time when it appears from year to year,
and how it affects the amount of light and dark penetrating down into
the ocean. In this experiment, students can observe how brine shrimp react
to changes in their environment, which somewhat parallel the above phenomena.
Ensure that students understand brine shrimp are "stand-ins"
for the krill they'll see in the videos. Review with students the Krill
to Kill? Blackline Master #10, so they
understand something of the actual life cycle of krill and the conditions
they face.
Explore
Procedure
1. Organize class in research teams, hand out Activity 1.1.1 Student
Worksheet, "How Do Brine Shrimp React to Physical Stimuli?",
review materials list, and lab procedures. Have students complete their
hands-on investigation.
2. When all groups have finished their investigations, have research
teams share their results and discuss. Were all results the same? What
might account for any differences? Which variables were difficult to control?
Expand/Adapt/Connect
Referring to the krill data sheet, could students replicate the entire
life cycle of krill in the pack ice by freezing brine shrimp in the lab?
Why or why not? Explain. Response should go into their assessment portfolios.
Sea ice is easily tracked by satellite and infrared imagery. Link
from the LFA 2 Web site to other sites, such as those maintained by the
Palmer LTER group, NOAA and NASA, to see how the ice grows and retreats
with the seasons.
Last Update: 1/18/97
Comments on the LFA Web site: Webspinner.
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