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Unformatted text preview: Biology 1M03 Tutorial 6 | Ecological Footprint & Lichen Ecology Student Package Objectives !"Students will determine their own ecological footprints and critically evaluate their choices and impact on the earth !"Use data collection skills to infer the effects of pollution on lichen abundance and diversity ! Read Box 54.1 (p. 1237) and Section 54.3 “Human Impacts on Ecosystems” (pp. 1238‐ 1241) in Freeman’s Biological Science, 3rd Ed. ! Use the online Ecological Footprint Calculator found at http://www.royalsaskmuseum.ca/gallery/life_sciences/footprint_mx_2005.swf to determine your footprint ! Fill in the Ecological Footprint Worksheet (p. 3) and bring it to class. ! Read the Introduction (p. 1‐2) in this tutorial manual ! Complete the ELM pre‐tutorial quiz ! Calculator ! Printed Student Package Preparation Materials This tutorial will help you to understand how human activity can affect ecosystems. In the first exercise, we consider how each person’s impact on this planet leaves an Ecological Footprint. In the second part of the tutorial, you will analyze actual data on lichen abundance, testing the hypothesis that air pollution is related to decrease lichen species richness and abundance. Introduction to Lichens Lichens are dual organisms that are composed of a fungus and a photosynthetic symbiont, or photosymbiont. Lichens do not belong to any particular kingdom because they are not singular organisms, instead deriving their identity from the close, symbiotic association of two organisms (The Canadian Encyclopedia). The fungal component of the association generally forms the majority of the biomass of the lichen, providing protection and the supply of minerals and water, while the photosymbiont supplies the lichen with organic carbon via photosynthesis. The photosymbiont is usually a type of green algae but may occasionally be a form of cyanobacteria. The structural and metabolic properties of the lichen develop only when the fungus and photosymbiont grow together, and many of the component species of lichens cannot survive independently in nature (Kaufman, 1989). Lichens tend to colonize flat surfaces, forming slow‐ 1 growing (approximately 0.1 mm per year) sheets taking one of three growth forms: foliose, fruticose, or crustose. Lichens are widespread, commonly colonizing extreme or stressful habitats where limitations in water, temperature, or nutrients preclude other forms of life. As such, lichens are often seen in the Arctic and Antarctic, as crusts on desert soils and on the surfaces of rocks and trees. Lichens are known to survive in various niches, on arctic soils at temperatures as low as ‐20!C or desert rocks whose surface temperatures may exceed 50!C (Kaufman, 1989). However, lichens are not limited to these harsh environments, and are in fact abundant in numerous biomes including tropical and temperate rainforests where biodiversity is rich. Lichens play an important role in colonizing new surfaces and are sometimes referred to as “pioneering” organisms because they are the first to colonize a previously uninhabited niche. Lichens may serve as a food source in places where vegetation is scarce. In Canada, lichens are eaten by arctic animals including caribou and reindeer, and are occasionally eaten by humans. Lichens obtain water and nutrients from rainfall, dissolved minerals in the air and by secreting metabolites onto the surfaces they inhabit. Among the metabolites excreted by some lichens are acids, which have the capacity to degrade surfaces and release minerals for uptake. However, lichens’ affinity for extracting nutrients from their surroundings makes them vulnerable to contamination and destruction by airborne pollutants (Kaufman, 1989). These pollutants, such as sulphur dioxide (SO2) and nitrogen dioxide (NO2) have the capacity to be taken up by lichens and have the general effect of reducing species abundance and richness (Sivanesan et al, in preparation.). The absence of lichens may be indicative of a polluted environment. Later in this tutorial, we will collect and analyze data on lichen prevalence at four sites in the Hamilton area, two in industrial areas and two in conservation areas. 2 Bio1M03 Tutorial 6: Ecological Footprint Worksheet Use the following worksheet to record information about your Ecological Footprint and bring your sheet to class. Be sure to complete the ELM pre‐tutorial quiz, which contains questions about Ecological Footprints, before next tutorial 1. What is your Ecological Footprint? _______________________ 2. Which of the four sectors contributes most to your footprint? _______________________ ________________________________ ______ 3. What single change, within the above sector, would reduce your footprint the most? ______________________________________________________ 4. Which three countries have the highest average Ecological Footprints? ____________________________________________ __________________________________ _____________________________________________ 5. What is the worldwide average Ecological Footprint? ________ ______ _____________ __________________________ _____________ ______ 3 Lichen Ecology: Data Collection Exercise The objective of this tutorial is to learn to identify three foliose lichen species and analyze whether they can be used as indicators of air pollution. The lichen species chosen for this study can be easily identified according to their distinct morphology and does not require any chemicals and further identification; therefore, making them ideal for use by the general public to assess air quality. Xanthoria fallax is an orange‐yellow lichen that has wavy, hood‐like lobes, having hairy undersides known as rhizines. The other two lichens are grey and can be differentiated by their lobes and other characteristics. Physcia milligrana is a grey lichen that has very small lobes and possesses a lot of powdery granules, while, Parmelia sulcata has big lobes with very fine ridges on top (their thallus). The three lichens studied are represented by the following images: In‐tutorial activity You will assess the abundance of three lichen species on five trees at four sites in the Hamilton‐ Burlington area. The SO2 levels of the sites are ranked as follows: Woodland park > Beasley park > Columbia college > Burlington site. Each lichen species are to be scored by assigning them a value between 0‐3 as follows: no lichens found on the tree 1 or 2 small colonies several small or only a few large colonies a lot of large colonies (at least 5 colonies, most are large) Once the abundance of each lichen species is scored, you will calculate the average abundance of each lichen species per site by adding the sum of the score from each tree and divide by the number of trees scored (five) that should give you an average score between 0‐3. 0‐ 1‐ 2‐ 3‐ 4 Tables 1. A‐D: Fill the following tables by assessing the abundance of lichen species per site 1A. Columbia College (SO2 of 4 ppb) Name of lichen species Tree #1 Tree #2 Tree #3 Tree # 4 Tree # 5 Average abundance Physcia millegrana Xanthoria fallax Parmelia sulcata 1B. Burlington site (SO2 of 2.5 ppb) Name of lichen species Tree #1 Tree #2 Tree #3 Tree # 4 Tree # 5 Average abundance Physcia millegrana Xanthoria fallax Parmelia sulcata 1C. Beasley Park (SO2 of 5.5 ppb) Name of lichen species Tree #1 Tree #2 Tree #3 Tree # 4 Tree # 5 Average abundance Physcia millegrana Xanthoria fallax Parmelia sulcata 1D. Woodland Park (SO2 of 7.5 ppb) Name of lichen species Tree #1 Tree #2 Tree #3 Tree # 4 Tree # 5 Average abundance Physcia millegrana Xanthoria fallax Parmelia sulcata Table 2. Record and compare the average abundance of each lichen species according to site Name of lichen Woodland Park Beasley Park Columbia College Burlington site (SO2: 7.5 ppb) (SO2: 5.5 ppb) (SO2: 4.0 ppb) (SO2: 2.5 ppb) P. millegrana X. fallax P. sulcata 5 Post‐tutorial assignment 1. Create a line graph (not a histogram) that shows the relationship between lichen species using your results from Table 2. Plot average abundance (y‐axis) against SO2 data (x‐axis) for each site. Plot all three lichens on a single graph, so that three separate lines represent the three lichen species. Be sure to clearly distinguish between the lichen species. You may create your graph using computer software such as Excel or you may draw your graph by hand. Attach your graph as a separate sheet with your assignment. Remember to include your name and student number on the graph. 2. Answer the questions on the Post‐Tutorial Report and hand in, with the graph attached, to your tutorial drop box by 1pm the day following the tutorial. References Kaufman, P. (1989). Plants: Their Biology and Importance. Harper & Row Publishers: New York. Brodo, I. (No date). Lichen. In The Canadian Encylcopedia Online. Retrieved July 17, 2008, from http://www.thecanadianencyclopedia.com Sivanesen, D., Richardson, D., McCarthy, S., Dudley, S., Finkelstein, E, Nieboer, E., and Sorger, G. (No Date). Use of lichens to develop a local air pollution scale, Hamilton, Canada. The Royal Saskatchewan Museum. (No date). Ecological Footprint Calculator. Retrieved July 17, 2008 from http://www.royalsaskmuseum.ca/gallery/life_sciences/footprint_mx_2005.swf Image References “Xanthoria fallax” http://www.pbase.com/terrythormin/image/58991652 “Physcia millegrana” (Unknown Author). http://www.eman‐ rese.ca/eman/ecotools/protocols/terrestrial/lichens/hardwood/physcia.html [Accessed July 17, 2008]. “Parmelia sulcata”. (Unknown Author). http://www‐ biol.paisley.ac.uk/research/Asilverside/lichens/Parmelia_sulcata.html [Accessed July 17, 2008]. 6 Bio1M03 Tutorial 6: Lichen Ecology Post‐tutorial Assignment Name:________________________________________ Tutorial Section: ____________ Student #:_____________________ TA:___________________________ Marks 1. I have attached my line graph of lichen abundance and SO2 levels " 2. Which of the three species is most tolerant to high levels of SO2? 3. Why might we measure the abundance of three different lichens species rather than just one? /6 /1 /1 4. Scientific research demands that experiments use a “test” that is both valid and reliable. Reliability means the test will produce the same results every time. Validity means the test measures what it intends to measure. Consider our lichen data collection method as a test for predicting air quality: What aspects might be considered problematic in terms of reliability? What aspects might be considered problematic in terms of validity? Give two examples: /2 Total /10 /10 7 ...
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