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pcb4043_review_exam1_las - Review for Exam I PCB...

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Unformatted text preview: Review for Exam I PCB 4043  ­ Spring 2010 These questions are meant to 1) give you an idea of the style of exam questions you might expect from us and 2) highlight some of the concepts we feel are most important. These review questions are by no means inclusive of everything that will be on the exam but we highly recommend using them in your studying. Please email and/or schedule office hours with us if you have questions. At first, the number of questions may seem overwhelming. However, if you have been attending the lectures, reviewing the powerpoints and reading the book, you should be able to answer them quickly. If you are having trouble answering these questions, use this as a constructive indicator that you might have a fair amount of work to do before the exam. Answers are due on Thursday, 25 February before 11am and will count as one homework assignment. To limit the pages you need to print, you can create a separate document with just your answers. Some answers require sketching diagrams or graphs, which can be done using Word or you can just draw by hand. This homework assignment will be graded as pass/fail and will not be returned. The answers are in red. If you have questions, let me know! I’m interested in what you think. I will have normal office hours (after class) and then additional office hours (510 Carr) on Tu and Wed next week from 1 ­3pm. If those hours don’t work for you, email me ([email protected]) and make an appointment. Or, if you have a quick question, I can try to answer it over email. I’ll be out of town this weekend but will respond as soon as I’m back in front of my computer. Questions from Laura  ­ ­ ­ ­ Scientific method and experimental design 1) Think about the following observations and questions: A naturalist notices that some white oak leaves are partially eaten by caterpillars. The naturalist then wonders, why aren’t more of the leaves being eaten? She then sees a bird swop down and eat a caterpillar. Provide a hypothesis that also includes a prediction about a possible causal factor. Possible hypothesis: Birds control the size of caterpillar populations. Therefore, in the absence of birds, there would be more caterpillars and greater herbivory of the oak leaves. Another possible way of writing this : There will be fewer caterpillars and lower rates of herbivory of oak leaves when bird density is greater. 1 There are many right answers! However, just saying ‘Herbivory changes in the presence of birds’ is not a good hypothesis. Do you understand why? 2) We discussed four sets of research approaches: Basic v applied; Theoretical v Empirical; Correlation v Experimental. Consider these four groups of approaches for the following questions. a) A researcher is studying how freshwater invertebrates respond to increases in water temperature in an attempt to make predictions about future effects of climate change. They set up microcosms that are set at three different temperatures, add invertebrates and monitor responses. Is this experiment basic or applied? applied Is it more theoretical or empirical? empirical Is it best described as a natural correlation or experimental approach? experimental b) A researcher is studying phosphorus cycling in a wetland. Their study involves sampling 15 different tropical and subtropical wetlands. They collect data from these wetlands and look for trends between variables such as pH, rates of litter turnover and redox conditions. Is this study theoretical or empirical? empirical Does it appear to use a correlation or experimental approach? correlation c) One of the interests of H.T. Odum was to better understand energy flow through ecosystems. In one of his studies on this topic, he uses models to compare Ohm’s Law in physics to energy flow in ecosystems. Is this study best described as basic or applied? basic Is this study theoretical or empirical? theoretical Scientific method – 3) Which of the following conclusions is/are not based on the scientific method? a) I considered the effect of water on plant growth and I feel like the plants with less water are the same size as the watered plants, meaning water doesn’t have an effect. b) Shearwaters are always found burrowing and nesting underground, which means that their eggs are easily predated upon if they are laid aboveground. c) Evidence of climate warming is Al Gore’s statement that the glaciers are melting on Mt. Kilimanjaro. None of these are based on the scientific method! The scientific method involves reflective inquiry and conclusions are based on the results of hypothesis tests. Remember, the scientific method involves: 1) making 2 observation and identifying patterns, 2) generating hypotheses, 3) making predictions, 4) conducting tests and experiments. Conclusions are then based on the data collected from tests and experiments. (Review Lecture 1). 4) Consider the following observations about seed toughness and beak size: The medium ground finch (Geospiza fortis) subsists mainly on seeds that it cracks open with its beak. During times of high seed production, preliminary data suggests that the hard seeds are avoided and the soft seeds are preferred. The past year, however, was a drought year and few seeds were produced, meaning soft seeds are not as abundant. You suspect, from reading the literature on other systems, that individuals with larger beaks should be better able to crack open large seeds. Write an appropriate hypothesis that specifies a prediction about a causal factor. Hypothesis: The average beak size of medium ground finches will increase after a year of drought because the medium ground finches with larger beaks will be more successful at accessing food and will therefore have higher survival and higher reproductive success than finches with small beaks. 5) Recent data collection shows that marine reserves are found to have higher biodiversity than other nearby areas. A news report covering the story states that more money needs to be given to marine reserves because they have been shown to have significant positive impacts. What is wrong with this interpretation? How could you design a more appropriate test of the effectiveness of marine reserves? The study lacks a control so good conclusions cannot be drawn. It may be that the reserves had higher diversity before they were established, and perhaps this diversity would have persisted even without being designated as reserves. To evaluate the effect of reserve status on biodiversity, areas inside and outside the reserve area should be studied before and after the initiation of the reserve regulations. It’s important that the unprotected areas that are being evaluated should include habit that is of high enough quality to have been considered for reserve status. Physical environment Thermal properties of water 6a) In a temperate lake in the fall, water is cooling at the surface. At one point, the surface water is 7°C and the deeper water is warmer. What happens to the 7°C surface water? It sinks b) The same lake continues to cool as winter approaches. Now the surface water is 3°C and the water below is 4°C. What happens to this surface water? It floats 7) Name three properties of water that make it unique and give an example of how each property that you chose is important in either climate or life processes. 3 Here are some example answers but there are many other possible answers:  ­ High specific heat. This means that compared to other compounds, it takes a lot of heat to raise one gram of water by 1°C. This is important in creating sea and land breezes, which can regulate local climates.  ­ Below 4°C, density decreases with decreasing temperature. Ice floats so the surface of a lake can freeze while organisms continue to survive in deeper water.  ­ Hydrogen bonding. Bonding between hydrogen and oxygen of different water molecules allows plants to transport water to their leaves through transpiration. Wavelengths, the atmosphere, albedo and greenhouse gases 8a) Draw a pie chart showing the relative abundances of N2, O2, CO2 and CH4 in the atmosphere. (Methane is such a small sliver of the pie chart that you can’t see it. But, remember that even though there isn’t much of it, it is a strong greenhouse gas. This graph has argon on it, which the question didn’t ask for, but you get the point.) b) Which of these are greenhouse gases? CO2 and CH4 c) Why are these greenhouse gases and the other(s) isn’t/aren’t (only a very brief explanation needed and include wavelength in your answer)? CO2 and CH4 absorb and reradiate longwave radiation, meaning longwave energy doesn’t ‘pass’ as easily through them as does through N2 and O2 . 9) You are listening to the news and hear that a large track of boreal forest has burned. The reporter then states that although the burn released CO2 to the atmosphere (which could contribute to increased global warming), scientists are suggesting that changes associated with postfire surface albedo may negate the effect of CO2 released to the atmosphere. It’s been shown that the loss of overstory canopy after fire can result in increased snow exposure during spring and fall. Relying on what you know about short and longwave radiation, answer the following questions to set the context for explaining the reporter’s statement. a) Does the majority of the sun’s energy entering the atmosphere enter as short or longwave radiation? shortwave 4 b) Which has higher albedo – snow or green boreal trees? snow c) When the sun’s radiation is absorbed (as opposed to reflected) is the average re ­ emitted wavelength longer or shorter? longer d) Does it have higher or lower energy? Lower energy e) Which wavelengths (longer or shorter) ‘pass’ more easily through greenhouse gases? Shorter wavelength energy Temperature and Q10 10) Look at Figure 1. a) Which insect species (A or B) has a higher Q10? b) Write a sentence to explain what this means in terms of the effect of temperature on the species metabolic rate. Figure 1. O2 consumed (uL per g per h) A B 10 20 Temperature (C) Species A has a higher Q10 than Species B. For a 10°C increase in temperature, Species A has a greater increase in oxygen consumption than Species B. This means that the metabolic rate of Species A has a greater response to temperature change. 11) We discussed four main avenues of heat gain and loss  ­ convection, conduction, evaporation, radiation. Pick the example below that best matches each avenue. a) A lizard sitting on a hot rock. Conduction b) Warm air rising. Convection c) A puddle drying out after a rain. Evaporation d) The energy emitted by the sun. Radiation 12) Sooty terns are known to nest in full sun and they rely on the water in their bodies to maintain a reasonable body temperature. a) What is this cooling process called? Evaporative cooling 5 b) Why does this process cool the bird? The heat energy surrounding the bird is used to evaporate water instead of increasing the temperature of the bird. In other words, the heat is used to create a state change (latent heat) instead of a temperature increase (sensible heat). Climate and soil Climate 13) What is the main driver of global climate? differential heating 14) a) Why is the equator hotter than the poles? (one sentence) b) Draw a simple diagram that shows the Earth and incoming solar radiation to explain your answer. At the poles, the same amount of radiation is distributed over a larger surface area. 15) What drives global atmospheric circulation (list two things)?  ­ Latent heat flux  ­ Coriolis effect and winds 16) a) In latent heat, what is the heat used for, or how is the heat consumed? Change in state (ex liquid to gas) b) In sensible heat, what is the heat used for? Change in temperature 17) Draw the solar equator on Figure 3 a and b. Figure 3. 6 !" #" 18) a) What is the Intertropical convergence zone (ITCZ)? The ITCZ is the region where surface currents of air from the northern and southern subtropics meet near the equator and begin to rise under the warming influence of the sun. b) What important climate cells have their origin at the ITCZ? Hadley cells 19) The global climate that is predicted from differential heating and atmospheric circulation is modified by a number of factors. Answer the following questions about how some of these other factors modify climate. a) Florida’s coasts are strongly influenced by sea breezes during the day. Do land masses heat and cool faster or slower than oceans? Faster b) Why? Land has a lower specific heat than water, meaning it takes a smaller change in energy to increase or decrease land by 1°C compared to the same mass of water. c) Draw the air circulation pattern on the diagram below. d) What is the effect of a sea breeze – does it warm or cool the land during the day? It cools the land during the day. !"#$ %#&'$ e) Mountain ranges can create rain shadows. Use the diagram below to explain what a rain shadow is. For arrow 1 and 2, indicate the relative temperature and humidity of the air. For arrow 3, label the relative humidity. Shade the area that is the rain shadow. 7 &$ '$ %$ !"#$ arrow 1 – warm, moist air; arrow 2 – cooler, moist air; arrow 3 – dry air, brown line shows the rainshadow State/ soil forming factors – 20) In central Florida, about 20 MYBP, a shift in tectonic plates caused streams from the mainland to deposit sediment along the Gulf Coast. At about the same time, shifts in plates also created slight uplifting in other nearby areas (for example, near Ocala), creating outcrops of carbonates, but both areas are relatively flat. We visit two sites – a site with the old sediment deposits is currently covered with pine flatwoods, mainly slash pine. The site we visit with carbonate outcrops has sandhill vegetation (scattered longleaf pine with turkey oak and sand post oak). List the five soil forming factors and state if they differ between the sites. (from p 36 in Ecosystems of Florida) Parent material and biota are different Climate, topography, time of soil formation are the same You could also argue that the biota isn’t all that different – there isn’t really enough info given to say one way or the other for sure so I’d except either. Soil texture – 21) The landscape of the Great Lakes region was heavily influenced by glacial retreat 10,000 years ago. Due to the way glaciers deposited debris as they retreated, some parts of the landscape are very sandy while other soils have much higher percentages of silt and clay. a) If you visit two sites that are relatively close to each other, and therefore receive similar amounts of rainfall and have similar temperature, which site (the sandy site or the site with more silt and clay) will have more water a few days after rain? The site with more silt and clay b) Which of these sites would likely have higher concentrations of total phosphorus, nitrogen and calcium? The site with more silt and clay (because clay has greater surface charge than sand) Biomes 8 22) Provide a brief definition of a biome. Categories of ecosystems and communities based on climate and vegetation structure (growth form, size, density) 23) Use the outline of a Whittaker diagram to complete the following. a) Where (in general) do you expect tropical rainforests (mark with a star)? b) Where (in general) do you expect tundra (mark with an open circle)? c) Where (in general) do you expect subtropical desert (mark with a square)? d) What are two factors that may make important contributions to biome categorization that are not included in the Whittaker diagram? Disturbance and soil type 24) Consider two areas that receive 50 cm of MAP, but one area has a MAT of 20°C and MAT of the other is 7°C. a) Which is more likely to have more water available for plant use? The site with lower MAT. b) Why (one sentence is fine)? The site with the higher MAT would likely have greater evapotranspiration. 25) Consider the following Walter climate diagram and answer the questions that follow. 9 a) Which site is likely to be limited by water during a large part of the potential growing season? Lisbon b) In which site(s) does the growing season last all year? Lisbon and Sitka c) In which site(s) does precipitation appear to be aseasonal? Sitka 26) Use the Holdridge life zones diagram below for the following questions. a) An important general distinction between arid and non ­arid zones can be seen on the Holdridge life zones diagram. This distinction occurs at the potential evapotranspiration ratio of 1. Highlight this line/border on the diagram. b) The potential evapotranspiration ratio is defined as PET/precipitation. If potential evapotranspiration ratio is greater than one, is the site arid or non ­arid? arid c) Why? Above one means the PET is greater than the precipitat...
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