AP BIOLOGY Investigation #10 Energy Dynamics Summer 2014 - - PDF document

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AP BIOLOGY Investigation #10 Energy Dynamics

www.njctl.org Summer 2014

Slide 2 / 26 Investigation #12: Fruit Fly Behavior

· Pre-Lab · Guided Investigation · Independent Inquiry

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· Pacing/Teacher's Notes

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Pacing/Teacher's Notes

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Slide 4 / 26 Teacher's Notes

Lab procedure adapted from College Board AP Biology Investigative Labs: An Inquiry Approach Teacher's Manual Click here for CB AP Biology Teacher Manual

Note: This investigation will be assessed in the Ecology Unit (lab quiz located with Ecology assessments). This investigation takes approximately 3-4 weeks to complete, thus it is planned to begin during the Evolution & Classification unit. However,

• rganisms used require careful attention so please plan accordingly, keeping

in mind school holidays/breaks.

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Pacing

Day (time) Activity General Description Reference to Unit Plan Notes Day 1 (HW) Pre-lab Pre-Lab questions EC Day 16 HW Day 2 (40) Guided Practice Getting Started, NPP Step 1 EC Day 17 Day 3 (40) Guided Practice NPP Step 2, Planting EC Day 18 Grow for 7 days. Have students think about independent inquiry and approve designs prior to next lab day; new plants must be started. Day 4 (40) Guided Practice NPP - mass young plants; Plant new seeds for Independent study EC Day 23 Grow an additional 7 days Day 5 (80) Guided Practice NPP - mass

• lder plants/

young independent study plants; Analysis and EF Steps 1-2 Eco Day 3 Mass fecal matter every day for next 3 days. Day 6 (40) Guided Practice EF Steps 3-4, Analysis Eco Day 7 Day 8 (40) Independent Investigation Begin new larvae for Independent Study Eco Day 8 Mass fecal matter every day for 3 days (or as directed by independent investigation design) Day 9 (80) Independent Invesigation Analyze independent data EP Day 12 Day 10 (40) Independent Investigation Prepare presentation EP Day 13 Day 11 (40) Presentations Peer review presentations EP Day 14 Day 12 (20) Assessment Lab Quiz EP Day 15

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Pre-Lab

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What factors govern energy capture, allocation, storage, and transfer between producers and consumers in a terrestrial ecosystem?

In this lab we will: · Design and conduct an experiment to investigate a question about energy capture and flow in an ecosystem. · Explain community/ecosystem dynamics, including energy flow, NPP, and primary and secondary producers/consumers. · Predict interspecific ecological interactions and their effects. · Use mathematical analyses in energy accounting and community modeling. · Make the explicit connect between biological content and the investigative experience.

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Read the background information and answer the following questions in your lab notebook.

• 1. Explain how energy flows through an ecosystem.
• 2. Contrast net and gross productivity.
• 3. What type of ecosystem/biome would have the greatest net primary

productivity? The least? Explain your reasoning.

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Safety

Cabbage white butterflies (Pieris rapae) are listed as a pest species by the USDA. Therefore, no butterflies or larvae raised in the laboratory should be released to the wild. Euthanize the butterflies or larvae by freezing them when your investigation is

• complete. The plants and soil can simply be discarded.

Disease outbreaks are common in cultured populations of

• rganisms. Although the diseases associated with the
• rganisms in this investigation are not dangerous to humans, it

is important to maintain cleanliness in the laboratory and of your experimental equipment to minimize possible impacts on the study caused by disease. Be sure to clean all culturing chambers and wipe down with dilute bleach and dry completely before starting another generation of plants or butterflies. Use new materials if you have any doubts. Cultures involve artificial light sources and liquids; caution should be exercised to keep the two separate.

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Guided Investigation

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Materials

· Food dehydrator or drying oven · Electron balance · Digital camera · Growing system · Soil mix · Soluble fertilizer · Wicking cord · Fast Plant seeds · Butterfly eggs · Brussel sprouts, broccoli, and/or cabbage · Honey · 10% bleach solution · Bee sticks · Laboratory notebook

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Estimating Net Primary Productivity (NPP)

Step 1 In your lab notebook, design and construct a systems diagram to model the energy capture and flow through a plant. Use annotations to help explain your reasoning. Step 2 Your energy diagram will help you and your lab team design a data collection procedure that helps you measure energy capture and flow in a plant. As a team, design your investigation to sample the biomass of of an adequate number

• f plants early in the life cycle and then again later in the life
• cycle. Remember, biomass is only the mass of the DRY plant

material, not of the water in the plant. Make sure your procedure accounts for this.

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Analyzing Results

In your notebook, graphically present a comparison of the biomass/energy of plants early in their life cycle versus early plants. · Determine the average (mean) grams of biomass added per plant over the period of growth. Each gram of plant biomass represents about 4.35 kcal of energy. Convert grams of biomass/day to NPP (kcal/day). · Explain why this is net primary productivity and not gross productivity. · Explain why the mass of dry plants is a better measure of primary productivity and biomass than is the mass of living

• plants. What percentage of the living plants is biomass?

· Reconstruct your energy flow diagram with actual data that you have collected. Be sure to include an explanation, supported by evidence, as to why you feel your diagram represents energy flow in Fast Plants.

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Estimating Energy Flow

Step 1 Cabbage white butterfly larvae eat plants from the cabbage family. As with Fast Plants, accounting for energy flow into and out of these butterflies can be inferred from biomass gained and lost. In your lab notebook, develop a system diagram to model energy flow from Fast Plants to cabbage butterfly larvae.

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Estimating Energy Flow

Step 2 As butterfly larvae grow toward maturity, they pass through different developmental stages called instars. You will use larvae that are already well along their developmental path through the larval stages (4th or 5th instar). These larvae first grew on young Fast Plants, and they were later transferred to brussels sprouts (another member of the cabbage family) in a Brassica Barn. For this part of the investigation, you and your lab team need to develop a procedure that will quantify the growth of butterfly larvae over three days. Started with freshely massed brussels sprouts in the Brassica Barn.

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Estimating Energy Flow

Step 3 Create a table in your lab notebook to organize the data collected, including estimates of energy/biomass flow from plants to butterfly larvae. Develop your procedure keeping in mind your end goal - to measure the biomass consumed by the larvae, the biomass gained by the larvae, and the biomass lost by the larvae. Likely, you'll need to estimate some factors using data from a large sample. Don't forget about the energy in the frass (wastes). Step 4 Transfer the larvae to another Brassica Barn to finish

• ut their life cycle.

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Analyzing Results

Convert biomass measurements (grams) to energy units in kilocalories. · You were investigating living butterfly larvae, so you could not dry them or their food supply. Assume that the biomass of 4th instar larvae is 40% of the wet mass. (This estimate may be inaccurate, so you should actually measure this quantity using extra butterfly larvae, if possible. · To convert butterfly biomass to kilocalories, use an average value of 5.5 kcal/g of biomass. · To determine the energy content of the larval frass, use 4.76 kcal/g of frass. Calculate the frass lost per individual larva. · To determine the energy content of the brussels sprouts eaten by each larva, convert the wet mass of the sprout to dry mass (using NPP results) and multiply by 4.35 kcal/g. This estimate was determined by burning similar plant material in a bomb calorimeter.

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Analyzing Results

These procedures are similar to an energy audit. Because energy is neither created nor destroyed, you must account for all energy in the system. Combine your two earlier energy flow diagrams into one, and now include all the information that you measured. For those energy pathways that you did not explicitly measure, provide an estimated energy quantity. Graph your results. If you use bar graphs for illustrating the means, standard error bars should be included to display the range of the data.

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Independent Inquiry

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Designing & Conducting Your Investigation

The following questions could be investigated, but you are not limited to these. · Do all plants have the same percentage of biomass? · Is the percentage of biomass the most important characteristic

• f a plant in terms of its effect on the growth of an animal?

· How do plants with different life strategies allocate biomass in different organs? · How much is allocated to reproduction? · How much energy is allocated to plant defense? · How much energy does it cost an animal to process different plant sources?

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Choice Chamber

Step 1 Prepare a choice chamber by labeling both ends with a marker - one end "A" and the other "B". If using plastic bottles - Cut the bottom of the bottles, dry the interior thoroughly, and tape them together. Remove any paper labels. Place a cap on one end of a chamber before adding flies. Insert a small funnel in the open end of the chamber and tap 20-30 fruit flies into the choice chamber using the funnel.

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Choice Chamber

Step 2 After the transfer, quickly cap the other end of the chamber. Step 3 Begin your study by placing a few (5-10) drops of distilled water on two cotton balls, and adhere one moist cotton ball to each end of the chamber. Do not add too much water or any other chemical to the cotton; too much liquid will drip down into the chamber and affect the experiment by sticking flies to the bottle. Step 4 Lay the chamber down on a white surface or on white paper. Step 5 Give the flies at least 5 minutes of undisturbed time, and then count the number of flies at each end of the

• chamber. Create a table to record the number of flies you

find at each end (A and B) of the chamber.

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Choice Chamber

Step 6 Begin to test each factor you are including in your

• investigation. After exposing the flies to the test chemical/

factor, lay the chamber down on a light colored surface (or on white paper) and observe the flies. Step 7 Give the flies at least 5 minutes of undisturbed time, and then count the number of flies at each end of the chamber.

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Analyzing & Evaluating Results

Quantify your results and express them graphically. Complete a chi-square analysis of your results. Evaluation Questions: · Is there anything that was shared by all of the environmental factors to which the flies were attracted? · Is there any that was shared by all of the environmental factors to which the flies were repelled? · How do you explain the behavior of fruit flies in someone's kitchen or in nature based on the information you collected? Do your data explain all fruit fly movements? Explain your answers.

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