Population Changes in Algae A Lesson on Ecology

Transcription

1 Retired High School Teacher Summer 2008 Lesson # 8 The American Physiological Society 2009 Works in Progress

2 Appropriate citation: Schiller, E. Population Changes in Algae: (APS Archive of Teaching Resources Item #2973). [Online]. Bethesda, MD: American Physiological Society, Editor s notes: Website URLs listed in this resource were current as of publication, but may now be obsolete. If you know of a replacement URL, please suggest it in the resource s Comments section The APS encourages teachers to give students a copy of the ABC (Appropriate, Beneficial, Caring) rules for use of animals in the classroom, to discuss the rules, and to ask students to sign the ABC rules contract (see References). Also, teachers should have a plan for short term care of the animals (with supporting references for appropriate care guidelines) and for disposal or long-term care of all classroom organisms. Teachers should carefully review any stimulus or environmental change for an animal being used in experiments or observations before students are allowed to use that stimulus. This is especially important if the stimulus could cause pain or distress to the organism. Teachers may be able to identify a less stressful stimulus for the students to use in their experiment. Although mammals provide excellent opportunities for observational studies, they require particular care in terms of handling and may cause allergic reactions in some students. The teacher should check local and state guidelines before using mammals in the classroom. Disclaimer: This activity was created by the author and reviewed by the American Physiological Society. Any interpretations, statements, or conclusions in this publication are those of the author and do not necessarily represent the views of either the American Physiological Society or the funding agencies supporting the professional development program in which the author participated. Frontiers in Physiology The American Physiological Society Permission is granted for workshop/classroom use with appropriate citation

3 PURPOSE OBJECTIVES GRADE LEVEL PRIOR KNOWLEDGE TIME REQUIRED INCLUDING ALL STUDENTS Students will design and carry out an experiment where they will observe and evaluate how algae population changes when subjected to environmental influences by using a variety of detecting methods like, using a Spectrophotometer or Spec-20 for analyzing algae population density through measuring transmitted and absorbed light passing through growth tubes. An alternative analysis could be done with the assistance of a color wheel or CBL-Colorimeter Probe. This laboratory will fit into any ecology class or a unit on population changes or in any biology class unit dealing with understanding population dynamics and photosynthesis. It could be used for advanced biology classes fitting into population changes, photosynthetic studies, and food chains. Upon completion of this activity, students will be able to: develop a lab protocol enabling the student to test a hypothesis. develop a lab procedure enabling the student to collect and analyze data on population changes over time. set up controls in experimenting with algae growing in differing environments. enable student to collect data on living organisms using algae as templates. develop lists of requirements for algal life. Activity is designed for 9 th -12 th grade students in Biology or Advanced Biology Classes. Activity can be easily altered for 7 th -8 th grade Life Science curriculum. This activity on algae should follow either a unit on population growth in ecology or a unit on photosynthesis. Some understanding of light infiltration or absorption of light through photosynthetic organisms will assist in this laboratory. Set up: 20 to 30 minutes for lab set up. Additional data collection: 5 minutes/week for as long as you want to collect data. Investigation could continue for an entire quarter or semester. Students should be able to work in small groups (groups of 2, 3, or 4) for this lab activity. Each laboratory group will be responsible for developing their own hypothesis, design their own set of laboratory conditions for algal growth, assess their own laboratory set up, collect their own data, come to their own conclusions, formulate summative class inferences, use technology to document their own data and class data, access computers for final assessment activities. Physically challenged individuals might need additional assistance with table model microscopes, laboratory equipment and testing areas.

4 QUESTIONS TO ASK ALONG THE WAY NATIONAL SCIENCE EDUCATION STANDARDS IOWA STATE SCIENCE EDUCATION STANDARDS What factors affect the growth of algae? When there is an overproduction of algae, what toxic substances are released? Can an overproduction of algae affect animal life? Could an overabundance of algae increase food reserves? Could an overabundance of algae be used as a renewable energy resource? How can your locality be affected by an algal bloom? What type of algae grows in your local area water? What affect might an algal bloom have on the global consequences of animal life? How can algal population shifts be used to model other population changes? What are the ideal conditions for algal growth? What occurs during an algal bloom that kills fish? Kills mammals? Grades 5-8 and 9-12 K-12 Unifying Concepts and Processes Evidence, models, and explanation Change, constancy, and measurement Evolution and equilibrium Science as Inquiry Understandings about scientific inquiry Life Science Populations and ecosystems Diversity and adaptations of organisms Interdependence of organisms Science and Technology Understandings about scientific inquiry Understandings about science and technology Science in Personal and Social Perspectives Populations, resources, and environments Population growth Science and technology in local, national, and global challenges Life Science 1. Understands and applies knowledge of the cell and the parts of the cell 2. Understands and applies knowledge of the inter-dependence of organisms 3. Understands and applies knowledge of matter, energy, and organization in living systems Science as Inquiry 1. Identifies questions and concepts that guide scientific investigations 2. Designs and conducts scientific investigations 3. Uses technology and mathematics to improve investigations and communications 4. Communicates and defends a scientific argument

5 MATERIALS For small lab groups (2-4 students) Glassware: beakers for collecting and growing algae glassware for growing algae (grow in test tubes with caps) test tubes - if you do not have screw caps, plastic wrap or Parafilm will work funnels for transferring algae solutions thermometers for measuring temperature variations Equipment: grow lights for light for photosynthetic requirements for algae growth microscopes for monitoring health of algae populations Spec-20 for analyzing transmittance and/or absorbance colorimeter a substitute for a Spec-20 for analyzing transmittance/ absorbance cuvettes for analyzing algae concentrations in Spec-20 or colorimeter color wheel can be used for quantifying algae concentrations computer for Internet articles on algae related information Consumable supplies: Parafilm or plastic wrap for covering containers marking pens for labeling tubes microscope slides/cover slips pipettes, either disposable or bulbous for transferring algal solutions thick paper construction paper for blocking light infiltration fertilizer for simulating field run-off into streams graph paper for data analysis paper towels for spills Parafilm is a registered product of the Pechiney Plastic Packaging Company SAFETY PREPARATION AND PROCEDURE Students should handle all computers with care. Students should handle all laboratory apparatus with care. Students should handle all laboratory probes and equipment with care. Students should handle all algae samples with care. Students should destroy of all algae grown in their lab with 10% bleach. *** When handling algae solutions and bleach solution, students should use protective gear-goggles, apron, and safety gloves. *** Description The lesson would begin with a discussion, a KWL chart about the productivity of algae, and the population changes in algae through a typical growing season. Have students check various websites and online resources while undergoing an Internet Treasure Hunt, garnering further information on the productivity of algae and the ongoing dispute of algal blooms across our environmental biomes and how their over productivity affects living systems. Suggested web resources could include Flood of 2008 showing flooding in the Midwest and the effects of run-off in streams and rivers, moving that run-off material to the Gulf of Mexico, and the creation of even a larger dead zone from the 2008 Flood. For suggested web links, see list of References and Resources at the end of this activity.

6 PREPARATION AND PROCEDURE For the inquiry piece, students could be given a sample of algae or the student could be given a collection container or allowed to bring in an algal sample collected locally. Either would work in order to get a sample of algae to grow and to collect data on. Teacher Tips: Use of uni-algal samples from major biological supply centers are a helpful resource for using one type of algae for the students in this laboratory. One additional note is by providing one type of algae from a uni-algae culture and having students growing them in a lab such as this will minimize variation of data. The students would be divided into small research groups to come up with a hypothesis and a way to use the Spectrophotometer (or Color Wheel or CBL- Colorimeter) to effectively assess population densities based on their team agreeing on the methodology and means of assessment of their findings. Based on the team s research design and the student s grade level, students would receive the instructor s approval of methodology. Students would begin creating the environment and environmental conditions deemed important as per the research group s experimental design. The student research group would then set up their experimental design, carry out their procedure, and collect their data, over time. After all the groups complete their laboratory and have compiled their data, class discussions of the group s findings would ensue. Class discussions could also occur weekly or monthly, giving summary of expected and real data of their algal growth experiments. A good final class summary would include students accumulating each of their classmate s data and summarizing their data on one table and one graph and then drawing conclusions on the best or most limiting method of growing algae. Preparation Make available locations for growing the student s algae, such as a window ledge, grow light over a bench, or something similar as the students might choose a location close to a light source. Make ample space for a Spect-20 or Colorimeter for testing their growth tubes of algae over time. For the other materials and supplies, have a space on a table or cart with the various materials placed for student selection once they design the inquiry to be tested. Supply sterile distilled water as a water source for dilution of the algae samples brought in, various fertilizer samples that the student might need, construction paper for some of the students that might choose lesser light infiltrating into the growth tubes, funnels, paper towels, plastic wrap or Parafilm to prevent the evaporation in case you do not have tubes with screw caps. Make available any materials that you think the student might select on a table or counter.

7 PREPARATION AND PROCEDURE WHERE TO GO FROM HERE SUGGESTIONS FOR ASSESSMENT Procedure After forming their research laboratory groups, students will be instructed on the components of the lesson design. Students will perform a KWL worksheet where the student group would fill out What They Already Know, What They Want to Know, leaving the What I Learned section blank. Then, student groups will present and the entire class will accrue a list of What They Already Know and What They Want to Learn from this topic. Then, using this initial basis of understanding, students could be sent on an Internet Treasure Hunt to selected websites. This activity may also be useful as an introduction to the balance of nature and the pros and cons of increased populations in the delicate ecological balances. A similar activity could be developed on fertilizer runoff on algae development in the dead zone. Advanced classes could also do a lab extension using ph paper or ph meter measuring the changes of ph on water supplies as algae population changes. Students could also collect data on local water sources collecting algae and determining types and varieties of algae are present in local aquatic sites and follow population changes over time. Students could provide a class discussion sharing their discoveries in their inquiry approach to their scientific problem, sharing their data in the form of graphic representation of their collected data. Students could develop laboratory reports summarizing their findings. Students could construct an environmental poster of their findings showing their investigative summary of their research. Students could turn in their KWL s and Internet Treasure Hunt summaries for assessment. Students could prepare an oral discussion of their group s KWL and/or Internet Treasure Hunt. Students could delve further into aquatic systems and their relative importance to algal population changes investigating how calcium carbonate increases/decreases are directly related to oxygen/carbon dioxide ratios in the oceans and how the change in algae has a global affect on the amount of calcium carbonate accumulates on the floor of the ocean.

8 REFERENCES AND RESOURCES 1. Flood 2008 Could Affect Dead Zone Area in Gulf This article relates the affect of flooding on the dead zone. Accessed in summer of Flood, Size of Gulf Dead Zone Grows This article deals with the size of the dead zone relative to the recent flooding. Accessed in summer of Global Warming and Algal Blooms in the Artic Website deals with algal blooms and the overall effect on the Arctic. Accessed in summer of The Growing Problem of Harmful Algae This article deals with the ever increasing problem with algae in the environment. Accessed article in summer of Harmful Algal Blooms This web link describes various harmful algae and how those types of algal blooms can affect living systems. Article accessed in summer of Harmful Algal Blooms and Human Stress ?cookieSet=1&journalCode=energy.2 Dealing with harmful effects of algal blooms on humans. Accessed in summer of Hunting Dangerous Algae from Space This article relates the importance of space science in tracking algal blooms. Article accessed in summer of Manatee, Sea Lion Death May Be Health Warnings to Humans Interesting article how sea mammals might be warnings to humans. Accessed in summer of Satellite Algae Monitoring This website deals with satellite monitoring algae accumulations across the world. This article was accessed in summer of Toxic & Harmful Algal Blooms Algae can be very toxic and this website relates toxicity in conjunction with concentration of algae. Article accessed in summer of 2008.

9 Student Section KWL What I Know What I Want to Know What I Learned Name Date Period Topic of Discussion: Algae Productivity as a Design Mechanism for Environmental Studies What I Know about this topic/question What I Want to know about this topic/question What I Learned about this topic/question Donnellson, IA

10 Internet Treasure Hunt Student Section Name: Date: This web info search will help you find information about algae and algae growth, as well as how local floods, like the Flood of 2008 and how events like this might affect. You will be looking at pre-selected web sites to answer each question. It is important to not only find the information at the site, but also to consider who wrote the site, what their purpose is in writing it, and how credible (accurate) you think the information is. Question 1: Who created this web site (organization, etc.)? Why did they create it? (check all that apply) How credible (accurate) do you think the info is? How is technology used to track algal growth? How is technology used to track algal growth? Site 1 Site 2 Hunting Dangerous The Big View on Tiny Algae Algae from Space /lo/plankton/index.html Study/Redtide/ To provide factual information To influence the reader s opinion To sell a product or service Very accurate Somewhat accurate Not very accurate To provide factual information To influence the reader s opinion To sell a product or service Very accurate Somewhat accurate Not very accurate What did you learn? Donnellson, IA

11 Internet Treasure Hunt Student Section Name: Date: This web info search will help you find information about how natural disasters, like the Flood of 2008, could effect algae and further effect aquatic systems. You will be looking at pre-selected web sites to answer each question. It is important to not only find the information at the site, but also to consider who wrote the site, what their purpose is in writing it, and how credible (accurate) you think the information is. Question 1: Question 2: Question 3: Who created this web site (organization, etc.)? Why did they create it? (check all that apply) How credible (accurate) do you think the info is? How could natural disasters, such as periodic flooding, effect aquatic systems? How has the Flood of 2008 in the Midwest effected aquatic environments in the Gulf? What causes environmental changes by the effects of flooding? Site 1 Site 2 Flood, Size of Gulf Dead Zone Flood 2008 Could Affect Dead Grows Zone Area in Gulf al-te.flooding21jun21,0, story To provide factual information To influence the reader s opinion To sell a product or service Very accurate Somewhat accurate Not very accurate To provide factual information To influence the reader s opinion To sell a product or service Very accurate Somewhat accurate Not very accurate What did you learn? Donnellson, IA