Project Brine Shrimp

Transcription

Project Brine Shrimp
2008 SMILE Summer Teacher Workshop High School Club Activities
Project Brine Shrimp
Project Brine Shrimp: Exploring Biological Effects of
Environmental Change
Material adapted from:
Science NetLinks Lesson Plans:
http://www.sciencenetlinks.com/lessons.cfm?DocID=103
Virginia Tech Science Education
http://www.tandl.vt.edu/scied/lessons/video_lessons.htm
Science Junction Lesson Plans
http://ncsu.edu/sciencejunction/terminal/lessons/brine.html
Introduction:
The growth and survival of organisms depend on the physical conditions of their
environment, often showing sensitivity to even the smallest changes. Organisms that
live in aquatic environments all have built-in adaptations to deal with changing levels
of salinity, temperature, pH and pollutants. For example, brine shrimp can survive in
both seawater and brackish water, thus can be found in salt lakes and brine ponds all
over the world. However, brine shrimp have no defense against predation, so can best
thrive in conditions in which their predators cannot, such as high salinity and
temperature. In this activity students will design and conduct an investigation with
brine shrimp to test their tolerance to environmental change.
Objectives:
Students will:
• Develop an understanding of how the growth and survival of an organism
depends on physical conditions of their environment
• Use the scientific method to design and conduct experiments with brine shrimp
• Produce a scientific report on results.
Materials:
Brine Shrimp Hatchery Kit
(Materials in bold are provided by SMILE)
Air Pump
Petri Dishes
Empty 2-litre Soda Bottle
Desk Lamp (with high watt bulb)
Microscopes
Magnifying Glasses
Acidic Liquid (e.g. lemon juice, vinegar, muriatic acid)
Distilled or aged tap water
Baking soda
2 Common Pollutants (e.g. motor oil, soap or bleach)
pH Paper
Non-iodized/rock salt
Thermometers
Droppers/Pipettes
2008 SMILE Summer Teacher Workshop High School Club Activities
Project Brine Shrimp
Materials provided are enough to support 20 students
Handouts/Overheads:
Student Information Sheet
Brine Shrimp Transparency
Procedure:
1. Before the class begins set up the brine shrimp hatchery
• Take the 2-liter soda bottle and cut off the bottom (where it starts to curve
inward)
• Turn the bottle upside down and screw it to the hatchery base
• Attach one end of the airline tubing to the bottom of the base and connect the
other end to an air pump, turning the air pump on. Place the air pump in a
location higher than the hatchery to prevent water getting into the pump when
switched off.
• Fill the bottle ½ full with distilled or aged tap water (dechlorinated); bubbles
should come from the air pump to aerate the water.
• Add one packet of hatch mix
• Place a desk lamp about 8” away from the bottle, try to keep the water temp
2. When the class begins, briefly introduce brine shrimp (use the brine shrimp
transparency) and their life cycle. Brainstorm with the students what they think brine
shrimp need for growth and survival plus what they think could affect these needs.
3. Inform the students they are to design and conduct experiments to test the
tolerance of brine shrimp to changes in physical conditions. Divide the students into 4
groups:
A pH
B Temperature
C Salinity
D Pollutants
Provide each group with a copy of the student information sheet.
4. Making the rest of the materials available, have the students plan their
experiments. The basic outline should include:
• Using droppers to place samples of brine shrimp eggs from the hatchery into
Petri dishes for testing
• Initial conditions in each sample are tested (i.e. pH, temp)
• Initial numbers of eggs/hatchlings should be counted prior to testing using
magnifying glass/placing Petri dish under a microscope
• Changes are made to the Petri dishes to change environmental factors;
o pH – adding acid (acidic liquid) or base (baking soda)
o Temp – warming/cooling the sample
o Salinity – adding salt solution/diluting the sample
o Pollutants – adding pollutants to sample
2008 SMILE Summer Teacher Workshop High School Club Activities
Project Brine Shrimp
•
•
Tests should use the scientific method, i.e. using defined increments to alter
the environmental condition (e.g. raising the temp a defined number of
degrees)
Designing an appropriate data sheet/method of analysis to record their results.
5. Once the groups are prepared for their experiments they can begin. Have the
groups leave their samples for a set time period (24 hours works best).
6. After the samples have been left, have the groups return to their experiment and
note any changes to the number of eggs/hatchlings under a microscope. They should
also note whether any initial hatchlings have survived (i.e. live shrimp will be moving)
and record all results.
7. Have the groups discuss their results and prepare a presentation
(oral/poster/PowerPoint) of the outcomes of their experiments and their final
conclusions.
8. Have the groups present their presentation to the rest of the class.
9. Summarize all group findings, adding context to the information with how this
relates to aquatic ecosystems.
Extensions:
1. If available, use flexi cams with the microscopes attached to a camcorder so the
students can record their brine shrimp samples before and after experimentation.
Use this video link to help:
http://www.tandl.vt.edu/scied/lessons/DV/brine_shrimp.htm
2. Have the students evaluate their experiments asking the following types of
questions:
• Were the results accurate? Why or why not?
• What improvements would you make to your method to increase the reliability
of the results you collected
• What advise would you give a salt lake conversation project to improve food
availability for larger organisms?
Vocabulary:
Diapause
A period of suspended development in an insect, other invertebrate or mammal
embryo especially during unfavorable conditions.
pH
The measure of the acidity or alkalinity of a solution. It is formally a measure of the
activity of dissolved hydrogen ions (H+).
Salinity
The saltiness or dissolved salt content of a body of water
2008 SMILE Summer Teacher Workshop High School Club Activities
Project Brine Shrimp
Project Brine Shrimp: Information Sheet
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Branchipoda
Order: Anostraca
Family: Artemiidae
Genus: Artemia
The common brine shrimp (aka sea monkeys) are a species of aquatic
crustaceans of the genus Artemia. They are closely related to zooplankton such
as Daphnia and are found worldwide in both coastal and inland hypersaline
environments, such as salt lakes. Aquarists often use them as live food for
saltwater aquariums.
Brine shrimp eggs are metabolically inactive and can remain in total
stasis for several years while in a dry, oxygen-free environment, even at
temperatures below freezing. This characteristic is called ‘cryptobiosis’ or
‘diapause’. Once placed in water the cyst-like eggs hatch within a few
hours, and will grow to a mature length of around one cm on average.
Brine shrimp have a short life span and, alongside other characteristics
such as their ability to remain dormant for long periods, means they are
invaluable to scientific research.
With your group design and conduct experiments using brine shrimp to test
how changes to physical environmental conditions affects their growth and
survival.
Specifications:
• Be resourceful and creative with the equipment/materials made
available to you
• Samples of brine shrimp should be tested in Petri dishes
• Make sure the initial conditions in each sample are tested and recorded
before making changes
• Make sure initial numbers of eggs/hatchlings are counted and recorded
prior to testing so you have something to compare results with!
• Have a control sample
• Tests should be specific and use defined increments to change conditions
by
• Make a data sheet and have an method of analysis that is appropriate for
collecting results
• Make use of your group! Divide and conquer individual tasks.
2008 SMILE Summer Teacher Workshop High School Club Activities
Project Brine Shrimp
Project Brine Shrimp: Brine Shrimp Life Cycle