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